How common for an ECU to throw in the towel?

Vortech347 · Post by **Vortech347** » Sat Sep 01, 2012 1:26 am

Well, trying to get my tune dialed in my car has gone apeshit. Literally. You name it... its doing it. From cruising at 10AF to wigging out so bad full pedal does nothing. Just sits at 1500rpm. Finally trying to get home I pulled the spout and the car drove perfect getting home. Even the tach glitched a little bit.

Is it my tune or is the ECU checking out. If it is checking out, where to get a new one? I don't want to get another used one because who's to say it won't crap out a month later.

Post by **cgrey8** » Sat Sep 01, 2012 7:02 am

Sounds like it could be J3 connection issues???? This is a test until you figure it out exercise here.

Vortech347 · Post by **Vortech347** » Sat Sep 01, 2012 6:24 pm

I took the ECU out today and the chip hadn't moved. (taped in) I did remove it and also take the case off the ECU to see if there were any burn spots on the board. Reinstalled all of it and it still did a few random weird glitches with the fuel and throttle. My logs don't show anything conclusive other than a few random 0's and dead spots in the logs. I've never seen that before so I'm not sure what I am chasing.

I also re-did my EGR/Wideband hook up directly to pin 27 on the ECU and its still not showing AF on my logs, its extremely frustrating.

LeadHead · Post by **LeadHead** » Sun Sep 02, 2012 5:36 pm

Check the capacitors for signs of leaking/bulging at the top. We've been seeing failed capacitors causing all kinds of weird drivability issues more and more often over at Ford-Trucks.

On second thought, if the tach was playing up - wouldn't that indicate a PIP/TFI issue?

decipha · Post by **decipha** » Sun Sep 02, 2012 10:03 pm

1st step in diagnosing possible ecu issues is to replace the ecu relay

2nd replace fuel pump relay

3rd reground ecu

if you unhooked the spout and the engine ran fine i would be lead to believe its a bad tfi module

Vortech347 · Post by **Vortech347** » Mon Sep 03, 2012 3:27 am

The fuel pump relay isn't a problem. TFI was replaced about a year ago, it only has about 2k miles on it tops. When the car wigged out it went INSANE rich, 10+ and I would loose any ability to throttle the car. Literally the gas pedal did NOTHING. FP remains constant. I am starting to wonder if loading tunes while the engine is on is a bad idea and causes weird results. Since I got the car running again I've been doing a lot of "driving tunes"

After checking things over yesterday I re-loaded the tune (engine off) and drove it today. Seems to be running better? didn't hic-up once?

EGR still isn't reading the WB though. I'm running a build 19 of BE 2010. Clint said he'd get me the most recent version. If anyone here has a link to it let me know maybe that is my issue with the WB.

If that doesn't work in getting the EGR/WB to log I may see if I can borrow a friends A9L. If it does work I'll know the ECU is fubar'd.

Where is the ECU relay located?

Vortech347 · Post by **Vortech347** » Mon Sep 17, 2012 1:48 am

What computers can I get as replacements?

Vortech347 · Post by **Vortech347** » Sun Sep 30, 2012 11:25 pm

Just an update to this. It went away for a week or 2 and today during a club cruise everything went to hell again. Since my last post I removed the EFI engine harness and checked the 10pin and also removed the injector adapters. I have EV6 injectors so I stopped by the local junk yard and got a set of the correct plugs. I soldered the EV6 ones on and inspected everything.

Today, I was on a downhill slope in a tight canyon and the car surged once. Then AF went MAX rich and I literally had no gas pedal. The engine was running. But only because the clutch was out. When I pumped the gas pedal the ONLY change was my boost gauge going from vacuum to 0. The car responded in no WAY. I quickly killed the ignition while rolling and flipped it back on. It cleared up. It also will do it but not as bad. It goes mega rich, then the car drives at 11.0-11.2 A/F for 2-3 minutes then clears up. So its not the exact thing every time but it always begins with 1 surge then insane richness.

It has done it several times today. I will be logging the hell out of it next few days and see if I can catch it on a log.

I will be replacing the EEC relay tomorrow along with double checking every ground on the car. I have a 4 gauge ground from the back of the head to the firewall. Should I add any grounds to the EEC? The one on it looked fine when I had it out a few weeks ago.

Oh. P.S. The 11 mustangs behind me all thought I had ruptured a fuel line because I had so much fuel odor coming from the car. In the car it smells like someone dumped fuel on the floorboards, its that bad. I seriously think my 60lb injectors were all held wide f'n open. Fuel pressure during the dreaded "glitch" stays where it should.

LeadHead · Post by **LeadHead** » Mon Oct 01, 2012 11:05 am

If the ECU processor fails, there's a secondary chip in the computer that fires the injectors a fixed pulse-width with every pip-pulse. If you have 60lb injectors in there, if it enters that "failsafe" mode, It's going to dump a ton of fuel into the motor.

Take your TFI module out and get it tested - most auto parts stores can test them.

I'm still betting on failed computer though. On the truck forums when the computers die, they just start doing crazy stuff most of the time. Stuck at high idle, poor running all the time, poor running some of the time, error codes that don't make sense, etc..

Vortech347 · Post by **Vortech347** » Mon Oct 01, 2012 11:44 am

I have a NIB spare TFI I will give that a try too.

Thanks guys.

Vortech347 · Post by **Vortech347** » Mon Oct 01, 2012 12:02 pm

A9S
A9P
A9t
C3w
C3W1
A3M
A3m1
A3M2
A9L
A9m

Is that a reliable list of ECU's I can get, install in my car and put my tune on?

decipha · Post by **decipha** » Tue Oct 02, 2012 1:52 pm

sure just be sure the aod/t5 hego harness is happy or remove pin 30 the nds

Post by **EDS50** » Wed Oct 03, 2012 3:40 pm

A quick test to check the ecm would be to check the stored codes and if you put a digital volt meter on the tps and it says 5.xx volts then its fubared. As a matter of fact I'm pretty sure any of the 5 volt sensors would read a max value when the ecm is bad. Check your pins in the 60pin ecm connector as well and make sure none of them are loose. TFI module either works or the car shuts off. Its that simple. Corrupt tune? Corrupt build of BE? Definitly replace fuel pump and ecm relays. Everyone with fox body cars have to realize these cars are about 20 years old and alot of these bugs are starting to surface.

Vortech347 · Post by **Vortech347** » Thu Oct 04, 2012 1:32 pm

Dumb question, where is the EEC relay?

My fuel system doesn't use the eec for power signal.

Vortech347 · Post by **Vortech347** » Thu Oct 04, 2012 1:32 pm

decipha wrote:sure just be sure the aod/t5 hego harness is happy or remove pin 30 the nds

So you are thinking its a wiring harness issue?

Also I did try to use an older tune that still worked on the car, problem still occurred.

Vortech347 · Post by **Vortech347** » Thu Oct 04, 2012 2:08 pm

Here is the tune on the car currently.

Post by **EDS50** » Thu Oct 04, 2012 2:31 pm

eec relay is on the pasenger side above the computer in the upper corner where the a pillar meets the windshield and firewall to the right of heater box under the dash speaker along the firewall if that all makes sense. It should have a dark green connector and is the only one up there. Its a bitch to get to.

Post by **EDS50** » Thu Oct 04, 2012 2:39 pm

Matt, this tune is f*cked. Ill fix it and post up.

Post by **EDS50** » Thu Oct 04, 2012 2:46 pm

Here.

E10tune60lbMatt3-Fixed-EDS50.BIN

Clear the KAMRF'S and Let me know.

Vortech347 · Post by **Vortech347** » Thu Oct 04, 2012 4:54 pm

EDS50 wrote:Matt, this tune is f*cked. Ill fix it and post up.

Oh damn. What did I screw up?

Vortech347 · Post by **Vortech347** » Sat Oct 06, 2012 4:53 pm

EEC relay changed going for a drive in a little bit. I hope this works.

Vortech347 · Post by **Vortech347** » Sat Oct 06, 2012 6:27 pm

Slap my ass and call me Suzzy.

It worked from what I can tell. I drove the car for about 30 minutes in stop and go, freeway, and a few full throttle runs. Nothing. Buck with fuel dump and cells with missing data.

EEC Relay FTW!!!

(watch now that I posted it next time I drive the asshole gremin comes back.)

Post by **cgrey8** » Sun Oct 07, 2012 11:15 am

It seems when EEC Relays go, it's unpredictable how they might fail. When mine went, I had intermittent surging and complete cut-outs that would come and go for either minutes at a time or would chatter the EEC ON and OFF making it feel like a horrendous miss condition. But the odd part is when the relay was failing, it was getting some juice to the EEC...just enough for it to operate a little. The engine would idle, but wouldn't do much more than that. I could also see a dim glow of the CEL when it was in it's "failed" state.

The thing that indicated the EEC relay to me was when I was down there checking the EEC, I noticed the relay was a bit warmer than a relay should be. So I decided why not change it, nothing else was making sense. And for me, it worked too.

I'm just amazed by how different TFIs and EEC relays can fail for people.

Vortech347 · Post by **Vortech347** » Mon Oct 08, 2012 2:31 pm

I took the car to an appointment today with a big smile. 35min later into it. I get the surge of death and engine goes mad rich. I got a log of it and will check it later. (On my phone). I'm so damn frustrated.

Vortech347 · Post by **Vortech347** » Mon Oct 08, 2012 5:13 pm

Logs. Trimmed down.

When it died at the stop light.

And when it bucked then went mega rich.

Vortech347 · Post by **Vortech347** » Wed Oct 10, 2012 7:14 pm

At this point should I replace the ECU or start going through my wiring harness with a fine tooth comb?

LeadHead · Post by **LeadHead** » Fri Oct 12, 2012 8:10 pm

Something whacky is happening. Take a look at 456.7195 and 457.7945 on the stoplight log. The ECT reading suddenly drops from 194* to 104*, VBAT drops from 13.68 to 12.9375, and VMAF jumps from 0.465v to 0.6946 volts. But then once the engine has about died, the ECT reading goes back up to normal. However VBAT settles in around 11.875v - which is extremely low.

The surge log also shows weirdness where VBAT suddenly drops way down, and everything stops reading correctly.

I'd go over all your power wiring and grounds with a fine-tooth comb. If you can't find anything wrong, pop the ECU open and look for signs of leaking/bulging capacitors or burnt components.

Vortech347 · Post by **Vortech347** » Fri Oct 12, 2012 8:22 pm

I have about 10 of these logs, and some will have 3-4 rows of data that is damn near nothing, Where EVERYTHING goes nuts.

My wiring is hidden in the fenders. This is going to be a pain in the ass.

Darkstar · Post by **Darkstar** » Sat Oct 13, 2012 6:13 am

Reading through this tonight, and had a couple of comments to pass on. 1) Going back to decipha's comment relative to the HEGO/Trans wiring harness, he was pointing out that you can use any of the processors on your shopping list PROVIDED that you either use a processor that matches your transmission and wiring type (auto or manual) or disconnect the trans position switch/clutch switch wiring (EEC pin 30), this will assure that you don't fry the EEC, as the manual trans cars are different from the automatic cars, one looks for a ground while the other gets a 12vdc signal. 2) I have seen some really strange behavior from injected cars when the power supply goes crazy. It is interesting that in both logs VBAT drops to what is probably battery voltage even though the engine is probably still turning the alternator. So either the excitation voltage droped out (ignition switch or the "little" connectors at the alterntor?), the alternator stopped alternating, the large power feed wire became disconnected, or there is a very high load like a short. As was pointed out, these cars are starting to be very well used cars, little things like the EEC and FP relays are starting to fail. You might check your ignition switch to be sure it isn't dropping out. Also take a look at the alternator itself and its associated wiring, including the fuse links where the alt power lead connects at the starter relay. Try data logging while wiggling that lead with the engine is running to see if you can induce the voltage drop. On high mile alternators the brushes can wear to the point where they don't make good contact anymore, and you can get voltage drop-outs because of that. Also, if you are still using the original type of alternator, they were notorious for frying the connector on the alternator main power wire at the alternator (where it breaks into a pair of spade-type connections). I looked at your injector offsets vs battery voltage and they look reasonable, but it wouldn't take too much voltage shift with 60 pound injectors to get to "pig-rich".
Dave

Vortech347 · Post by **Vortech347** » Sat Oct 13, 2012 5:07 pm

I replaced the ignition switch 2 years ago when I discovered I still had a factory one. (Which was partially melted).

The alt is a 3G with 4 gauge wire straight to the battery. I then have a 4 gauge ground going from the body to engine.

I've been looking at the diagrams and I'm going to add another ground for the EEC right next to it and give that a whirl.

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