[parksjm7]

Background:

Engine hesitated during light load then surged unpredictably making it difficult to accelerate smoothly, and occasional rough engine running. When I turn off the engine, I heard a faint chirping or squeaking noise that I think has to do with the wastegate (because I didn't hear it when I disabled the turbos) I tried a number of things including boost solenoid, plugs, coils, BL coils, chargepipe, etc. and nothing worked.

2FCA and 2FDA codes were always present. I've read these codes are benign shadow codes as result of having a tune.

I had an old Procede unit (Rev 2.5SE) installed maybe 7 years ago. I figured that was causing the codes to come on but never suspected it to cause the hesitation.

I confirm that removing the procede fixed the hesitation, at least in my case.

Two weeks ago I removed the procede, and ever since the hesitation went away and no squeak /chirping noise was heard on engine shutoff. Also, the 2FCA and 2FDA went away.

I've no idea what went wrong with the procede piggyback unit but it's been obsolete for a number of years now, and I've read the 2FCA/2FDA is a sign of signal interruption. My guess is that something went south in the procede unit and it was causing resistance in DME signal communication causing hesitation / delay in engine response.

Now I'm finally able to enjoy my car again.

I've been searching for years how to correct my problem and could not find a solution in the forums, I hope someone finds this helpful like many other posts on this forum that helped me in the past.

[Ilma]

2FCA and 2FDA are shadow codes that have nothing to do with the Procede.

Many flash only tunes throw those same codes, and I have had them present on my car for almost a decade now.

I still use a procede unit for methanol control ONLY and have a customized flash that adjusts the fuel scalars and AFR's to run meth.

Back in the spring, I started to have severe throttle oscillations and eventually threw several simultaneous false codes such as O2 sensors, Throttle adaptation, camshaft sensor and a couple of others. I know that all these modules would not fail at the same time, so I suspected the Procede unit.

Those codes disappeared as soon as I removed the wiring harness and the procede unit.

I then reinstalled the procede and the codes did not reappear.

I suspect that corrosion was causing voltage fluctuations on the pin connectors of the wiring harness.

Disconnecting and reconnecting the pin connectors probably scraped the contact surfaces enough to re establish normal voltage signals.

Not sure if that is your problem, but it's easy enough to clean your connectors on the procede wiring harness and reinstall to see if the problem clears up or not.

[parksjm7]

Ilma - thanks for sharing your experience – my thoughts:

Originally Posted by Ilma

2FCA and 2FDA are shadow codes that have nothing to do with the Procede.

Many flash only tunes throw those same codes, and I have had them present on my car for almost a decade now.

Agreed that they are shadow codes not specific to Procede. In my case however, I’m running MHD V8 stage 1 93 octane now and the shadow codes have not come back. At the same time – the engine is running a lot smoother and without hesitation. I’m assuming that 2FCA/2FDA are not completely benign and would be part of troubleshooting a rough running car.

Originally Posted by Ilma

I suspect that corrosion was causing voltage fluctuations on the pin connectors of the wiring harness.
Disconnecting and reconnecting the pin connectors probably scraped the contact surfaces enough to re establish normal voltage signals.
Not sure if that is your problem, but it's easy enough to clean your connectors on the procede wiring harness and reinstall to see if the problem clears up or not.

I agree with you there that it’s likely something with the connections that interrupted the signals somehow. I’ve never used meth and while on the fly map switching is nice, I’m going to leave it out of my DME and just run MHD – one less component to fail.

[Ilma]

Originally Posted by parksjm7

Ilma - thanks for sharing your experience – my thoughts:


I agree with you there that it’s likely something with the connections that interrupted the signals somehow. I’ve never used meth and while on the fly map switching is nice, I’m going to leave it out of my DME and just run MHD – one less component to fail.

If you are not running methanol that is the best solution......no need for a piggyback to complicate signals when you can flash directly with MHD

[Unai]

Originally Posted by parksjm7

Background:

Engine hesitated during light load then surged unpredictably making it difficult to accelerate smoothly, and occasional rough engine running. When I turn off the engine, I heard a faint chirping or squeaking noise that I think has to do with the wastegate (because I didn't hear it when I disabled the turbos) I tried a number of things including boost solenoid, plugs, coils, BL coils, chargepipe, etc. and nothing worked.

2FCA and 2FDA codes were always present. I've read these codes are benign shadow codes as result of having a tune.

I had an old Procede unit (Rev 2.5SE) installed maybe 7 years ago. I figured that was causing the codes to come on but never suspected it to cause the hesitation.

I confirm that removing the procede fixed the hesitation, at least in my case.

Two weeks ago I removed the procede, and ever since the hesitation went away and no squeak /chirping noise was heard on engine shutoff. Also, the 2FCA and 2FDA went away.

I've no idea what went wrong with the procede piggyback unit but it's been obsolete for a number of years now, and I've read the 2FCA/2FDA is a sign of signal interruption. My guess is that something went south in the procede unit and it was causing resistance in DME signal communication causing hesitation / delay in engine response.

Now I'm finally able to enjoy my car again.

I've been searching for years how to correct my problem and could not find a solution in the forums, I hope someone finds this helpful like many other posts on this forum that helped me in the past.

Hi, I just wanted to thank you. My car has been having the exact same symptoms as you since I bought it 2 years ago. It even had a 30ff code when the engine hesitated because the turbo was not spooling at all.

I discovered that it had a JB4 installed in Map 0. I have finally removed it and all my problems have been solved!! Now my car has instantaneous turbo response, no matter how long I drive it. No jerking, no hesitation, no lag, no crankshaft sensor errors.

So yes, those piggyback ECUs can cause signal interruptions and latencies, as we have both experienced.