[martroy]

I’m using 2 EDIS8 modules cause wiring them in serie will lower the output and it’s for a blown application.

Here’s the issue : No SAW input is connected at the moment so EDIS are working in « Limp mode » and timing should be rock solid 10 degrees. When engine is idling (higher than 850 RPM), timing is moving from 10 to 16 to 14 to 12 to 10 to 16 etc… I’ve checked Coil A from both EDIS modules and the issue is the same. To rule out VR sensor and noise, I’ve moved the VR and trigger wheel on a bench drill and taping timing marks on it. While key in run position, when bench drill is turning, timing is 10 degrees rock solid !!!

Any idea what should I look at?


Thanks for reading.

Martin

[cgrey8]

Interesting. So since an EDIS8 module only fires 4 coils, you have 2 EDIS8 modules to fire 8 COP coils. And since "waste" spark is harmless with coil packs, it's equally as harmless for the COP coils to be fired twice as many times as they really need to be.

As for the problem, I have no clue. I think it's fantastic that you confirmed proper behavior on a drill. That eliminates a lot AND confirms your understanding of how things should work. But why it is misbehaving on the vehicle, I'm not sure. But if I had to guess, I'd say this is somehow related to the engine. I don't know how, but it's almost as if the engine's rotational acceleration is going up and down while at idle causing the timing to drift like that. What's more interesting is that it's drifting in the pattern. It almost makes me wonder if its jumping to 16 for some reason, then dropping by 1/2 degree per cylinder. So for every 4 cylinder fires, you see 2 degrees drop down to 10, then the cycle repeats. It's be interesting to know what the advance is doing on each of the other cylinders.

I also wonder if there's a chance the floating SAW input is being interpreted intermittently as 16. Try grounding the SAW input just to see if maybe it's floating and causing erroneous advance. If it is intermittently interpreting a floating SAW input as 16, it wouldn't surprise me that some internal algorithm gradually drops the advance by 1/2 degree per cylinder back down to 10. However if that were the case, I wouldn't think it would be so rhythmic. You'd see it run at 10 for a while, and periodically jump, then work its way back down to 10.

Again, all this is just me speculating with ZERO experience with any EDIS. So I could be completely wrong (and probably am). However in the absence of any other responses (yet), I thought I'd respond with my thoughts.

[martroy]

hey cgrey8, thanks to have taken time to read. Just to let you know, I've test with SAW input and if I command fixed 20 degrees (10 base + 10 added), I will get the same symptoms but 10 degrees higher. When I gave you number like (from 10 to 16 to 14 to 12 to 10 to 16), its moving very fast but this is to explain is not jumping from a "specific timing number" during few seconds but jumping every seconds.

I just dont think misfiring will cause timing light to show timing moving but more missing engine beat for a cycle. I ordered Coilpack to rule out COP installation and because it's will be the "normal installation - 1 EDIS module + 2 coilpack" and will start from there. Otherwise, I have no clue!

[cgrey8]

At least you've eliminated that a floating SAW isn't the problem.

When you tested on the drill, were BOTH EDIS modules working or were you testing a single one. If you were only testing one, then I'm wondering if there's some kind of interference between the two that's causing this.

I can't remember, but I believe EDIS, like TFI, has a feedback line back to the EEC doesn't it?

Another thing I thought about that you might want to test is what Cylinder 6 is doing. Cyl 1 and 6 should fire together. So it might be interesting to see if Cyl 6 is also firing with this odd behavior or if it is firing correctly.

As for the odd advance jumping around pattern, you said some things that now have me doubting my interpretation of your words. Can you make another attempt at explaining exactly what you are seeing?

[martroy]

When I was bench testing, I did the exact same thing as on the car cause I've just moved VR sensor and trigger wheel, nothing else. So both EDIS were tested that way.

Spout for TFI or SAW for EDIS is an output from EEC for advance only. When I remove jumper (Spout), it base timing from distributor or limp mode for EDIS module (10 degrees or what the index of VR sensor and missing tooth is).

When I was saying : "I’ve checked Coil A from both EDIS modules and the issue is the same.", is exactly what you suggested: Cyl 1 and 6, if it's the same thing = yes.

The jumping pattern, there is none. Instead of having a rock solid steady timing at 10 degrees, it's moving between 10 and 16 every split seconds.

I've ordered Coilpack and will see if issue remains the same. I'm not the first to do TFI to EDIS but with COPs, it's a bit rare. Will report back.

[martroy]

Received coil pack this week so hook them up on 1 EDIS like Ford did and........everything is working fine, timing rock solid at 10 degrees in limp mode!

Tomorrow, I will try to hook up 1 coilpack on Coil A and B of EDIS and connect Coil C and D of EDIS 2 just to rule out Coilpack vs COP. If issue persist that way, will try diode on both VR input on EDIS module. What you think guys?

[cgrey8]

Sounds like a reasonable plan. I wouldn't have guessed that there'd be cross-talk between the two EDIS modules. But being they were never intended to operate that way, anything's possible.

Congrats on being the first to do something...and figuring out the issues for the rest of us.

[martroy]

Today, I've tried 2 EDIS with coilpacks and it's working.

I've used:

EDIS 1
Coil A to Coilpack 1 pin1
Coil B to Coilpack 1 pin3

EDIS 2
Coil C to Coilpack 1 pin1
Coil D to Coilpack 1 pin3

That test shows us 1 VR sensor for both EDIS is not an issue in any way. The only thing different is COPs. I just dont understand how COPs could affect "base timing" from EDIS and how to fix it. Any ideas are welcome ?

[jsa]

I've read somewhere, EDIS monitors coil flyback voltage.

How do the coil primary and secondary resistances compare?

How about primary current and duration?

[martroy]

I've read somewhere, EDIS monitors coil flyback voltage.

How do the coil primary and secondary resistances compare?

How about primary current and duration?

Hi John, I dont have exact numbers in my head now but remember it was "the same thing". Will take a look later today and report back.

EDIT: I've checked and coil primary is 0,5 ohms and secondary is 5,84k ohms.

Dont understand how could I know "primary current and duration", would you please explain me?
Lastly, how it could affect timing when engine is running but on bench, everything is working fine? (Timing)?

Thanks

[jsa]

"the same thing".

Ok, I thought COP would be different to Wasted Spark Coil pack.

Dont understand how could I know "primary current and duration", would you please explain me?

It would require a scope.
EDIS sets dwell based on current rise to a constant value, as i understand it. Coil Impedance is the combined resistance and inductance.

Lastly, how it could affect timing when engine is running but on bench, everything is working fine? (Timing)?

After your coil pack test you said;

The only thing different is COPs.

I understood that to mean installed on car...yes/no?

EDIS monitors for coil faults. It's conceivable that EDIS could have a diagnostic mode if coil current and therefore dwell are not as expected.

As for the bench, power supply will be different to in car.

Don't rule out multiple issues conspiring together.

[cgrey8]

The other thing that's different about the bench is the engine isn't running. So the resistance across the spark plugs is different. When a spark plug fires in normal atmosphere, which is presumably how the coil was firing a plug on the bench, the relative resistance of the spark plug after the ionization of air into a spark is quite low. It's hard to imagine an air-gap having a low resistance, but ionized air is actually quite conductive. However when an engine ignites air and fuel, it does so under the conditions of compression. While highly compressed ionized air still is conductive enough to carry a spark, the resistance is notably higher. As a result, the voltage that is allowed to build in the secondary coil is MUCH higher than if the spark plug is fired in open air. This also explains how in coil pack wasted spark setups, the voltage "knows" to go to the cylinder that is under compression despite their being 2 plugs in the circuit, not just 1. The current jumps the plug that is in the cylinder currently being exhausted far easier since the combusted gasses are under much lower pressure (and thus have a lower resistance once the spark forms) on the exhaust stroke than they are on the compression stroke.

Circuit_2resistors.jpg

In the case of a series connected 1k and 10k resistor, the voltage across the 10k will be 10x the voltage across the 1k. In the case of 2 spark plugs wired in series, which is what you have with coil packs, the plug under compression will have a significantly higher resistance than the other plug...hence how the voltage "just know" how to go to the correct cylinder.

Point being, when the voltage changes significantly within a coil, that has an affect on its inductance and thus the impedance that is experienced/measured. If the EDIS module is monitoring the current flow through the coil, the current will be different on a plug firing in open air than under compression.

I don't know that this makes any difference to this discussion. But it is another difference that's easy to overlook/ignore. It may be that the coil pack coils have a different winding ratio than the COP coils do and thus different inductance even if the meter-measured resistance is similar.

[martroy]

Did one last try today with 1 EDIS and COPs wired in serie as described here: https://www.diyautotune.com/support/tec ... mod-motor/

Having the same issue, timing is jumping and car is not running well.

Here's a summary of all tests done.

2 EDIS (8 outputs) with 1 output to each COP = Engine runs but timing jumping and not running well
1 EDIS (4 outputs) wired in parallel = having spark but engine wont start
1 EDIS (4 outputs) wired in serie = Engine runs but timing jumping and not running well

1 EDIS (4 outputs) with 2xCoilpacks = Engine runs perfectly
2 EDIS (used 2 output from each one) with 2xCoilpacks = Engine runs perfectly

I have no ideas was is the cause of this?

[cgrey8]

I don't know why, but it's clear the EDIS module doesn't like the COP coils.

[martroy]

Finally, I've ordered an other set of brand new COPs, same model. It's now working fine. (Dual EDIS with COPs) Thanks everyone.

[jsa]

Were the first set new or used...same or different suppliers?

[martroy]

Were the first set new or used...same or different suppliers?

Both set were new but from different supplier.

[Roseline27]

"the same thing".

Ok, I thought COP would be different to Wasted Spark Coil pack.

Dont understand how could I know "primary current and duration", would you please explain me?

It would require a scope.
EDIS sets dwell based on current rise to a constant value, as i understand it. Coil Impedance is the combined resistance and inductance.

Lastly, how it could affect timing when engine is running but on bench, everything is working fine? (Timing)?

After your coil pack test you said;

The only thing different is COPs.

I understood that to mean installed on car...yes/no?

EDIS monitors for coil faults. It's conceivable that EDIS could have a diagnostic mode if coil current and therefore dwell are not as expected.

As for the bench, power supply will be different to in car.

Don't rule out multiple issues conspiring together.

Hello,
I was wondering the same thing, but tell me what do you think is different from the COP of the Wasted Spark Coil pack?