Halp! EEC IV CEL Flash that makes NO SENSE

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Tamnakz
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Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Thu Oct 19, 2017 8:07 am

I've joined here to help me try to solve a 'gremlin' problem in my '89 E150.

Engine is a 300 straight six, manual transmission.

I have this gremlin. The check engine light flashes at me. It is not in sequence, or trying to spit out codes. It acts like a short of some kind, but I can't find one and don't know where else to look. The flash is throttle/speed dependent. The colder it is, the less throttle/speed needed to start it flashing. This 'flash' does not store a code, nor does it actually turn the check engine light on. Only flashes, and never in any sequence.

*smashes head against wall*

A few examples:
-starting out on a cold (50f or below) day nearly any throttle that's more than about twice my idle will make the light flash. When it's cold, if I get to a speed where it makes it want to flash, breaking that speed makes the light stay on, but as soon as a neutralize it turns off.
-with a warm engine on a warm day, sometimes I'll get no light. Often, somewhere between 45 and 65mph in fifth I'll start getting a flash. It'll flash at one speed with a lot of throttle, but I'll be able to back off the throttle and drive without the light flashing.
-Only a few times, when the engine has been cold and it's cold weather, it has flashed at me while I'm at a standstill, just goosing the throttle lightly.

I have pretty thoroughly been through the grounding system.
I have swapped computers, this problem occurs with three different computers. One a reman, two looked original. It's worth noting, the only time the vehicle has actually died on me was when one of the original computers failed. It appeared as if it was a 'norm' capacitor leak... but I haven't repaired it yet to know if that were the case.
I've chased the wiring everywhere except inside the bulk harness. I don't see any splices or worn wiring that looks like a plausible culprit.

Halp me! Please!
I love my van. It's basically my house. I want it to stop telling me to check the engine, unless there's a real reason to check the engine!

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skunk
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by skunk » Thu Oct 19, 2017 9:27 am

That is odd.... Is it a hard pulse or more like a flicker? As far as I know, the light can only come on with a ground signal. If it's not coming from the ECU you may need to trace the wire that should run between the ECU and the self test connector and self test connector to the bulb. You might even have to pull the guage cluster and look carefully at the trace ..... If it's starting to separate....it may be part of the problem.

Good luck
John
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by cgrey8 » Thu Oct 19, 2017 9:44 am

I remember have a similar, but different, issue a few years ago. In my case, the CEL would dimmly glow. It wasn't flashing or flickering, but it would intermittently glow and when it glowed, there was a chance that it would start surging the engine or watchdog-restarting the processor at random times which causes a very noticeable hiccup in power production from the engine. It was as though the EEC was operating on low voltage and what voltage it was getting was somehow being gotten THROUGH the CEL lamp and thus causing it to dimmly glow. I can't remember for sure what I did to fix it, but I vaguely believe it was a bad EEC relay that fixed it. The odd thing was I could datalog during these events and nothing appeared odd in the datalogs including reported Battery Voltage! Since the EEC can get voltage from multiple sources (i.e. Ignition, KAM, etc), it's possible the circuit monitoring battery voltage isn't the same as the one that it uses for main power.

Anyway, for what it's worth, try replacing the EEC relay just to see if this makes any difference. At the very least, you can eliminate that as a possibility.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Tamnakz
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Thu Oct 19, 2017 10:01 am

skunk wrote:
Thu Oct 19, 2017 9:27 am
That is odd.... Is it a hard pulse or more like a flicker? As far as I know, the light can only come on with a ground signal. If it's not coming from the ECU you may need to trace the wire that should run between the ECU and the self test connector and self test connector to the bulb. You might even have to pull the guage cluster and look carefully at the trace ..... If it's starting to separate....it may be part of the problem.

Good luck
John
It's more of a flicker. I can get a situation where it flickers, I keep on the throttle, and it comes full on, but as soon as I let off the throttle it goes off.

I don't know if I mentioned, there is NO running problem associated with the light. It might lost a tiny bit of torque, but that's questionable.

I've had the cluster out, as well as the panel where the CEL is located. I've traced the wires as well as I can without unbundling the wiring harness, and it all looks to be in great shape.

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by cgrey8 » Thu Oct 19, 2017 10:22 am

If it never happens on Closed Throttle, then that could be a bad Throttle Position Sensor(TPS). Although every time I've ever had a TPS go bad on me, it's always been the Closed Throttle condition that went bad and turned on the CEL thus the CEL went out as soon as I hit the throttle again and might-or-might-not come back on next time I returned to Closed Throttle.

Although if it were bad TPS, I would expect this to get logged in the EEC and thus get reported when you scan for codes.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Tamnakz
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Thu Oct 19, 2017 11:02 am

cgrey8 wrote:
Thu Oct 19, 2017 10:22 am
If it never happens on Closed Throttle, then that could be a bad Throttle Position Sensor(TPS). Although every time I've ever had a TPS go bad on me, it's always been the Closed Throttle condition that went bad and turned on the CEL thus the CEL went out as soon as I hit the throttle again and might-or-might-not come back on next time I returned to Closed Throttle.

Although if it were bad TPS, I would expect this to get logged in the EEC and thus get reported when you scan for codes.
If it were a TPS I'd expect to see a difference in running condition when it occurred, as well as a code.

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Thu Oct 19, 2017 11:05 am

cgrey8 wrote:
Thu Oct 19, 2017 9:44 am
I remember have a similar, but different, issue a few years ago. In my case, the CEL would dimmly glow. It wasn't flashing or flickering, but it would intermittently glow and when it glowed, there was a chance that it would start surging the engine or watchdog-restarting the processor at random times which causes a very noticeable hiccup in power production from the engine. It was as though the EEC was operating on low voltage and what voltage it was getting was somehow being gotten THROUGH the CEL lamp and thus causing it to dimmly glow. I can't remember for sure what I did to fix it, but I vaguely believe it was a bad EEC relay that fixed it. The odd thing was I could datalog during these events and nothing appeared odd in the datalogs including reported Battery Voltage! Since the EEC can get voltage from multiple sources (i.e. Ignition, KAM, etc), it's possible the circuit monitoring battery voltage isn't the same as the one that it uses for main power.

Anyway, for what it's worth, try replacing the EEC relay just to see if this makes any difference. At the very least, you can eliminate that as a possibility.
I've been looking at wiring diagrams... This kind of makes sense. It would explain why there wouldn't be a code stored, and gives a plausible explanation for why the light comes on.

I've had the light stay on for 5-8 seconds though, with no noticeable running problems. Makes me wonder how long the computer could/would keep everything going with the relay giving partial or no 'on' voltage.

I think a test drive with a jump wire could be an easy check though. If I can reproduce the light, pull over, swap the relay out for a jumper wire, and try to reproduce the light again... wish me luck!

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Thu Oct 19, 2017 4:05 pm

A relay is cheap enough to just purchase and replace regardless instead of wasting time on jumper wires.
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 8:03 am

EDS50 wrote:
Thu Oct 19, 2017 4:05 pm
A relay is cheap enough to just purchase and replace regardless instead of wasting time on jumper wires.
Yes, but a jumper wire eliminates the possibility of mechanical failure in a relay. A relay jumper wire should be in any mechanic/gearheads toolbox for diagnosis. There's no wasted time. I take a test drive, pull over, swap the relay for a jumper, and keep test driving. No 35 minute trip to the parts store, no money spent on something that's maybe bad.

Throwing parts at a problem is stupid. If I find a fault, I'll fix it, but until I do there's no point.

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 8:36 am

Tamnakz wrote:
Fri Oct 20, 2017 8:03 am
EDS50 wrote:
Thu Oct 19, 2017 4:05 pm
A relay is cheap enough to just purchase and replace regardless instead of wasting time on jumper wires.
Yes, but a jumper wire eliminates the possibility of mechanical failure in a relay. A relay jumper wire should be in any mechanic/gearheads toolbox for diagnosis. There's no wasted time. I take a test drive, pull over, swap the relay for a jumper, and keep test driving. No 35 minute trip to the parts store, no money spent on something that's maybe bad.

Throwing parts at a problem is stupid. If I find a fault, I'll fix it, but until I do there's no point.
So have you experimented with your jumper wire gimmick to rule out the EEC relay or any other relays or sensors? Me personally, I would use my dvm or power probe and start checking the relays and sensors directly related to what you are describing which I would suspect to possibly be ect/act tps or vss related and proceed from there. You may also want to check the EEC vip test port connector/harness and make sure nothing is going on with that. Are you using a tuner or chip? Verify the j3 port is clean. Do you have any datalogs when the issue is happening?
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 9:05 am

EDS50 wrote:
Fri Oct 20, 2017 8:36 am
Tamnakz wrote:
Fri Oct 20, 2017 8:03 am
EDS50 wrote:
Thu Oct 19, 2017 4:05 pm
A relay is cheap enough to just purchase and replace regardless instead of wasting time on jumper wires.
Yes, but a jumper wire eliminates the possibility of mechanical failure in a relay. A relay jumper wire should be in any mechanic/gearheads toolbox for diagnosis. There's no wasted time. I take a test drive, pull over, swap the relay for a jumper, and keep test driving. No 35 minute trip to the parts store, no money spent on something that's maybe bad.

Throwing parts at a problem is stupid. If I find a fault, I'll fix it, but until I do there's no point.
So have you experimented with your jumper wire gimmick to rule out the EEC relay or any other relays or sensors? Me personally, I would use my dvm or power probe and start checking the relays and sensors directly related to what you are describing which I would suspect to possibly be ect/act tps or vss related and proceed from there. You may also want to check the EEC vip test port connector/harness and make sure nothing is going on with that. Are you using a tuner or chip? Verify the j3 port is clean. Do you have any datalogs when the issue is happening?
No tuner, no chip, no logs. Stock EEC IV. J3 port, I'm presuming that's the multi pin port to plug into on the computers? It is, but even if it wasn't, I stated before, this problem has persisted with three different ECM's. My dad owned an independent shop for 20some years. When I couldn't solve my issue with my code reader, he plugged in his much fancier much more capable unit and redid the series of KOER tests as well as sensor tests my unit wasn't capable of. Still, nothing out of ordinary.

I have experimented with the jumper wire in place of the relay once. My time is limited right now, preparing for a trip. It's a common intermittent problem that's worse when cold. I started out on a test drive yesterday with the CEL flashing/flickering in every gear over about 1100rpm, which is as bad/common as the flickering light gets(we're getting our first cold nights here in Mi). I pulled over, installed the jumper wire, and drove like a bat out of hell, revving it out far more than my normal driving goes... no light flickering, except once when I let off of fourth gear at 60-70mph, and that was a single flash, nothing like the lights I'm used to seeing. So... I'm counting the test as inconclusive, because of that one little flash when I let off the throttle and neutralized, but otherwise, I've never been able to rev the engine out like I did on my test drive and not get a flickering light at upper rpms, since this problem began. When I got back I thoroughly cleaned the contacts on the harness and relay sides. I haven't been out to test drive again yet, but will soon. If I can repeat the light, I'll swap the relay for the jumper wire again, and see if things change. It's possible that even my jumper wire had an iffy connection the first time around, and it showed when the motor snapped back from full torque, but not super plausible.

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 9:11 am

EDS50 wrote:
Fri Oct 20, 2017 8:36 am
Tamnakz wrote:
Fri Oct 20, 2017 8:03 am
EDS50 wrote:
Thu Oct 19, 2017 4:05 pm
A relay is cheap enough to just purchase and replace regardless instead of wasting time on jumper wires.
Yes, but a jumper wire eliminates the possibility of mechanical failure in a relay. A relay jumper wire should be in any mechanic/gearheads toolbox for diagnosis. There's no wasted time. I take a test drive, pull over, swap the relay for a jumper, and keep test driving. No 35 minute trip to the parts store, no money spent on something that's maybe bad.

Throwing parts at a problem is stupid. If I find a fault, I'll fix it, but until I do there's no point.
I would suspect to possibly be ect/act tps or vss related and proceed from there.
The VSS does nothing for my vehicle, unless I'm mistaken. It could run cruise if I wanted to install it... Cable driven speedo, 89 EEC IV that pulls from a hall sensor in the distributor. My transmission has no worm gear on the output shaft to drive the VSS, hasn't in a decade. The wire to the VSS hasn't been hooked up in that time, but I have checked it to be sure it's free of shorts.

A TPS should give me drive ability problems, and if it were failing so regularly, should trip a light/code, should it not?

ECT same thing, should trip a light/code, should it not?

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 9:44 am

Well if the ecm is looking for vss input and the harness is disconnected from the sensor it should and will set a code to illuminate the cel. You mentioned you scanned for cel codes, we're there any? I think you results with your jumper merit the replacement of your EEC relay. The vss being disconnected may be the rest of the puzzle. If you had tuning capabilities (which is what this Web site is solely about) you would be able to turn off the vss in the tune and monitor/datalogs any other electrical anomalies that may be occurring.
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 10:15 am

EDS50 wrote:
Fri Oct 20, 2017 9:44 am
Well if the ecm is looking for vss input and the harness is disconnected from the sensor it should and will set a code to illuminate the cel. You mentioned you scanned for cel codes, we're there any? I think you results with your jumper merit the replacement of your EEC relay. The vss being disconnected may be the rest of the puzzle. If you had tuning capabilities (which is what this Web site is solely about) you would be able to turn off the vss in the tune and monitor/datalogs any other electrical anomalies that may be occurring.
I think I have a VSS code stored, but no check engine light for it. Are you sure it should trip the light, even on a vehicle that doesn't' use it for engine management?

I do realize this is a tuning site, which is why one of the first things I mentioned was that I joined here to solve a stock problem.

I have not had luck finding information about EEC IV that isn't available in my manuals, until I came here. I'm not tuning, but I know the folks here were the most likely to be able to help me narrow down or solve my problem.

The flickering cel without turning it on is what gets me. I've verified that the light will trip by unplugging the map/tps before. I can't understand why the CEL would flicker without actually turning it on. The EEC relay may fix it, I'll hopefully know when my driveway is clear for a test drive.

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 10:22 am

I would try disconnecting your battery to clear all codes stored in the kam and try running your jumper in the vss connector. Since you know you have a vss code it should make sense that the the cel is active. You should be able to go to any auto zone to have the codes read for free if you don't have access to a scanner or simple code reader.
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by skunk » Fri Oct 20, 2017 11:01 am

VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 11:23 am

skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
A non functional or disconnected vss will trigger a code and cel.

Jumping the vss is another way to force a signal. Same as the automatic ns jumper when performing a 5sp to at cinvetsion.
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Paulie » Fri Oct 20, 2017 11:45 am

EDS50 wrote:
Fri Oct 20, 2017 11:23 am
skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
A non functional or disconnected vss will trigger a code and cel.

Jumping the vss is another way to force a signal. Same as the automatic ns jumper when performing a 5sp to at cinvetsion.
Jumping vss connector will not do anything. The vss generates a voltage when moving. Jumping the vss connector will just connect vss signal wire to ground and you will still have zero volts. There is no circuit check on the vss in OBD1 vehicles.
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 11:54 am

Paulie wrote:
Fri Oct 20, 2017 11:45 am
EDS50 wrote:
Fri Oct 20, 2017 11:23 am
skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
A non functional or disconnected vss will trigger a code and cel.

Jumping the vss is another way to force a signal. Same as the automatic ns jumper when performing a 5sp to at cinvetsion.
Jumping vss connector will not do anything. The vss generates a voltage when moving. Jumping the vss connector will just connect vss signal wire to ground and you will still have zero volts. There is no circuit check on the vss in OBD1 vehicles.
Look into the strategy a little more and report back.
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by skunk » Fri Oct 20, 2017 12:19 pm

Lol.....it will verify the circuit and store a code 29 in continuous memory but won't throw a hard CEL in normal operation. You will only see it when running codes.

Edit..... I suppose the jumper could effectively eliminate any potential noise directly to ground that could get mis-interepreted leading to other issues.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Paulie » Fri Oct 20, 2017 2:07 pm

EDS50 wrote:
Fri Oct 20, 2017 11:54 am
Paulie wrote:
Fri Oct 20, 2017 11:45 am
EDS50 wrote:
Fri Oct 20, 2017 11:23 am
skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
A non functional or disconnected vss will trigger a code and cel.

Jumping the vss is another way to force a signal. Same as the automatic ns jumper when performing a 5sp to at cinvetsion.
Jumping vss connector will not do anything. The vss generates a voltage when moving. Jumping the vss connector will just connect vss signal wire to ground and you will still have zero volts. There is no circuit check on the vss in OBD1 vehicles.
Look into the strategy a little more and report back.
I'm always willing to learn. Show me where it says there is a circuit check on the VSS circuit. Code 29 is the only code for VSS and it is simply saying it didn't see a VSS input. Code 29 is only set as a continuous code not as an on demand code. You could do a KOEO self test with the VSS connector disconnected or jumpered and not get a code. Go out and drive the vehicle with the VSS connector disconnected or jumpered, come back and do a self test and you will have code 29 in memory.
1990 Mustang 5.0, HCI, Vortech S-trim, FRPP 42# inj., PMAS MH95, A9L, Moates Quarterhorse, BE/EA, Innovate LC-1.

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EDS50
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 2:47 pm

Paulie wrote:
Fri Oct 20, 2017 2:07 pm
EDS50 wrote:
Fri Oct 20, 2017 11:54 am
Paulie wrote:
Fri Oct 20, 2017 11:45 am
EDS50 wrote:
Fri Oct 20, 2017 11:23 am
skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
A non functional or disconnected vss will trigger a code and cel.

Jumping the vss is another way to force a signal. Same as the automatic ns jumper when performing a 5sp to at cinvetsion.
Jumping vss connector will not do anything. The vss generates a voltage when moving. Jumping the vss connector will just connect vss signal wire to ground and you will still have zero volts. There is no circuit check on the vss in OBD1 vehicles.
Look into the strategy a little more and report back.
I'm always willing to learn. Show me where it says there is a circuit check on the VSS circuit. Code 29 is the only code for VSS and it is simply saying it didn't see a VSS input. Code 29 is only set as a continuous code not as an on demand code. You could do a KOEO self test with the VSS connector disconnected or jumpered and not get a code. Go out and drive the vehicle with the VSS connector disconnected or jumpered, come back and do a self test and you will have code 29 in memory.
In Gufb its called VSSSW, VSTYPE, VSLOAD to name a few. However we are not talking about gufb considering its a 3.9 or 4.9 e150 van. The op already confirmed there is a vss fault code according to his findings. I am curious to know what other codes are present in his kam.
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by EDS50 » Fri Oct 20, 2017 3:32 pm

CONTINUOUS TEST STRUCTURE EEC-EPCD, FoMoCo, PROPRIETARY & CONFIDENTIAL

CONTINUOUS VSS TEST CONT'D


VSSSW=1 ----------------| | VSTYPE > 0--------------| | | | VSS FAILURE N >=VSMMIN -------------| | SET CONTINUOUS CODE 29 (ENGINE SPEED HIGH) | AND----| Manual & Auto | | | | VSSTMR >=VSSTIM --------| | (STABLE TEST CONDITIONS)| | | | VSBAR < VSSMN1 ---------| | (NO VSS READING) |---------ELSE------------ | | VSS IS OK | USE FAULT FILTERING 29 |


VSSTMR - VEHICLE SPEED SENSOR TIMER (.125 SEC) VSSTMR INCREMENTS WHEN THE PROPER CONDITIONS EXIST TO PERFORM A VSS TEST.


TFMFLG=0---------| (TP Sensor OK) | | TRLOAD < 4-------| (MANUAL TRANS) | | APT= -1 ---------| AND---| (CLOSED THROTTLE)| | OR----| | | | INCREMENT VSSTMR LOAD<= VSLOAD ---| | | (DECEL MODE) | | | | | | | | | |-------ELSE--------- TRLOAD = 4-------| | | | | | NDSFLG=1 --------| AND---| | SET VSSTMR=0 (AUTO IN DRIVE) | | | N >= VSAMIN -----| (ENGINE SPEED HIGH) For Auto Trans.







28-22
GUFB.pdf
(1.16 MiB) Downloaded 14 times
Refer to GUfb.doc for further explanation by typing vss in the search. I am sure the strategy calculations are relatively the same between the calibrations. What I am unsure about is if 8BA is the correct ecm in the op's van and how comparable it is to a9l
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 6:49 pm

skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
Thanks for the input. I've run codes with the paperclip method, a simple reader and a full on diagnostic shop grade unit. One koer test generated my gremlin flicker, but I've run dozens without it. The scanner didn't pick up anything to go with.

Coil is new, in fact, entire primary/secondary ignition is, save for the distributor and hall sensor. This is a cross country vehicle for me, that aside from this darn light, has been absolutely perfect to me. I preventative maintenance the fawk out of my vehicles though.

The theory with the EEC relay was mentioned to me on another forum. I didn't think much of it at first... but after about 35 minutes of staring at a wiring diagram for me ECM I came to the conclusion that it actually quite likely could be the cause of my problems. Both the fuel and ignition systems only need a ground switched by the computer to keep functioning. That means that the computer could lose a pretty significant amount of it's supply voltage without actually breaking those circuits. Could it lose enough to turn part of the computer off, but those circuits keep going? idk, it is possible, and it would explain why my light flickers, and it would also explain why there is no code associated with the flicker.

I've cleaned the terminals on the vehicle and relay, and am carrying around a custom made jumper wire that'll replace the relay with a temporary hard wire, which will hopefully let me rule out the relay. Intermittent problems suck... Since I posted this I've been driving both with the relay, and with the jumper wire. I have yet to get a flickering cel on the jumper wire, but an upcoming long trip will give me plenty of time to verify if I've done anything, or if intermittent bs is just being intermittent bs.

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 6:57 pm

EDS50 wrote:
Fri Oct 20, 2017 2:47 pm
Paulie wrote:
Fri Oct 20, 2017 2:07 pm
EDS50 wrote:
Fri Oct 20, 2017 11:54 am
Paulie wrote:
Fri Oct 20, 2017 11:45 am
EDS50 wrote:
Fri Oct 20, 2017 11:23 am
skunk wrote:
Fri Oct 20, 2017 11:01 am
VSS is used to tell the ECU your moving for other parts of the program. It will store a code but may not turn the CEL on since it's not critical for emissions.

Secondly......I'm not so sure putting a jumper across the VSS connection will offer any useful information since it supposed to generate a voltage pulse from the actual sensor.

Why don't you try running codes via the paper clip method to force the CEL flashes. When you get to koer tests keep an eye for flickering. I have a herd time thinking it's the EEC relay.......it would have to have a weak coil or some pretty crusty high resistance contacts to be a problem. If it's getting intermittent power.....you should be stalling or feel on heck of a hiccup throwing you back into crank mode. My thoughts are wiring or possibly the test connector itself if the terminals are sloppy and loose but I've been wrong before so replacing the relay may be the answer.

John
A non functional or disconnected vss will trigger a code and cel.

Jumping the vss is another way to force a signal. Same as the automatic ns jumper when performing a 5sp to at cinvetsion.
Jumping vss connector will not do anything. The vss generates a voltage when moving. Jumping the vss connector will just connect vss signal wire to ground and you will still have zero volts. There is no circuit check on the vss in OBD1 vehicles.
Look into the strategy a little more and report back.
I'm always willing to learn. Show me where it says there is a circuit check on the VSS circuit. Code 29 is the only code for VSS and it is simply saying it didn't see a VSS input. Code 29 is only set as a continuous code not as an on demand code. You could do a KOEO self test with the VSS connector disconnected or jumpered and not get a code. Go out and drive the vehicle with the VSS connector disconnected or jumpered, come back and do a self test and you will have code 29 in memory.
In Gufb its called VSSSW, VSTYPE, VSLOAD to name a few. However we are not talking about gufb considering its a 3.9 or 4.9 e150 van. The op already confirmed there is a vss fault code according to his findings. I am curious to know what other codes are present in his kam.
The only other code present in my kam is an egr code. I have a functioning position sensor but a stuck pintle. I do not get a check engine light from this code, and research previously led me to understand that's because my system is stuck closed, and thus doesn't pose an engine management problem.

I have tripped other codes, intentionally, via the map and tps for learning purposes, but the vss and egr are the only regular occurrences.

Tamnakz
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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by Tamnakz » Fri Oct 20, 2017 7:00 pm

EDS50 wrote:
Fri Oct 20, 2017 10:22 am
I would try disconnecting your battery to clear all codes stored in the kam and try running your jumper in the vss connector. Since you know you have a vss code it should make sense that the the cel is active. You should be able to go to any auto zone to have the codes read for free if you don't have access to a scanner or simple code reader.
My Mitchell on Demand, Ford, and 90% of anecdotal information on forums says the VSS won't throw a code for my vehicle. It's disconnect preceded my current problem by at least 8 years. Literally.

The battery has been removed as I swapped computers and checked wiring many times, my kam has been cleared at least 3 times in the last few weeks when the battery was out overnight, likely more when it was out for shorter periods...

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Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by LeadHead » Mon Oct 23, 2017 6:44 pm

Flickering light = bad PCM or intermittent power/ground/short to the PCM essentially causing rapid resets. Since you have tried multiple PCMs, it's a power issue.

The PCM relay and socket is a very common issue on these era vehicles.

decipha

Re: Halp! EEC IV CEL Flash that makes NO SENSE

Post by decipha » Sun Oct 29, 2017 12:50 pm

i had a similar issue a few years back except it was a full on code flash spitting out codes, she would do it randomly for no apparent reason, sometimes i would go months and other times i couldn't drive to the store and back without it happening numerous times

come to find out my o2 sensor wiring had melted on the exhaust and i had my sti wiring ran through that same loom, it would ground the sti and cause codes to spit out

was pretty evident it was spitting out codes though

just thought i'd mention

when diagnosing eec's the first step is to replace the ecu relay, or better yet jump it as you have

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