Is it possible they messed up some of the coil pack wiring when reaching over the engine?

 

Nope, as whole engine was dropped on subframe as-is, they wouldnt even open the coil cover I was told.

 

Did you have misfires before the engine was removed? if so, then I would think fouled spark plugs. The exhaust manifold leak could throw off the fuel trims or even cause it to go into limp mode (which would enrich the mixture to prevent engine damage)

I would check the ECM connectors, to make sure they're clean and plugged all the way in. Also, I'm thinking about a clogged fuel injector. It's possible some dirt/debris have gotten into the fuel line (that stays with the chassis) during engine removal preparation and made its way into the fuel rail, clogging up one or more injectors.

 

Unsure about 1st question - on last weeks before fix car was in terrible state - manifold squeal on lightest gas press, exhaust fumes in cabin, sometimes it choked or barely accelerated but I didnt read out Vida codes - just OBD reader returning "suction control valve stuck" error. If misfires were there i didnt notice it because of general state of the car unfortunately.

thanks for pointers ref ECM and injectors - will have that checked tomorrow.

 

That's a combo of codes, so I don't know is the short reply from me. By small chance when you pull plugs I will possibly agree with above post about oil fouled plugs. I pulled my plugs about 10K ago when recently bought the car, and there were small pools of oil in the plugs wells. I was getting codes for random misfires on 3 cylinders, and the car was misfiring, but still drivable. Not the correct thing to do, but I cleaned up the wells and plugs, and put them back. Correct way would be to apply new gasket from where it leaks into spark plug well but I chalked it up to wishful thinking that this is because the car has been sitting for a long time and some seepage has occurred. By guess/chance I thought sealants may expand and the leak will go away. It has been 10K since that and I have not had a misfire or misfire code since. Maybe I'll pull the plugs when I have time to see what's going on in there. Hopefully someone can piece together your combo of codes though

 

Why was motor dropped? So much more work when manifold is simple on these cars.
Id try swappin plugs/ coils to diff cylinders and see if misfire follows. If it doesnt may need to try swapping injectors to see if one is bad.
If problem persists can try simple compression test to see if engine is healthy. Could they have possibly left something in exhaust manifold like rag or something causing a clog. Seen bad cats cause lack of power/hesitation

 

Why was motor dropped? So much more work when manifold is simple on these cars.
...

Studs needed replacing aswell and my mech said its best way for him to do it this way, I cant argue with that. Thanks for advices, passed it forward, will see what he says


whiteblock850v50 - thanks, defo worth checking plugs, will do. Im not too worry of codes from 1st picture - it was directly after reconnecting engine etc, after clearing them so far the only ones recurring are the misfire (and airQ sensor that i keep ignoring for last 6years).

Been reading about some other cases of misfires etc and mine is not as consistent as other people's - car idles PERFECTLY, there is no codes coming up when revving on N or when driving gently. It only starts hesitating on accelerating and just THEN codes start showing up.
odd one :/

 

ECM 2900 fuel press code is probably from a faulty fuel pressure sensor. The fuel pressure circuit board solder joints crack and causes running problems. The code did not return yet because the circuit board did not heat up enough to open the cracked solder joints. I would replace the fuel pressure sensor on the end of the fuel rail, erase codes and retest. Do a battery cable reset. Remove and touch the battery cable together for 10 seconds or so. This will erase and reset the ECM stored RAM memory. Put rags under the fuel pressure sensor when removing it. Gas will drain into the alternator when removing the sensor. Also when your drop the 25mm torx screw, the rags will catch the screw.

 

ECM 2900 fuel press code is probably from a faulty fuel pressure sensor. The fuel pressure circuit board solder joints ...

thanks - will add to list of checks. Would FPS cause misfire errors? I used to have fps problem years ago when gotten the car (100k miles ago) replaced it then, but i dont remember reading out misfire codes ...

 

When the FPS failed on mine (at ~109k miles IIRC), I didn't get any misfires while driving, but the car definitely stumbled when it stopped reading correctly. It was an intermittent failure, it would read ~300 kpa then spike to 800 when it failed, a few minutes later it would go back to the correct reading and so on). And no misfires at all during cold starts.

 

When you do major combustion work on the engine (replacing the cat, fixing leaks in the exhaust etc) you might have to manually reset the fuel trims to 0 using the VCT2000 tool itself (or the one embedded in VIDA). If u don't then the trims may hunt around and never reset properly.

 

oh , thanks, thats interesting point - would those not be reset by long-term battery disconnection though?
Do you know how to do it using Vida? (what section to look for?) Have some knowledge of this tool, did Hilton update myself etc, just not sure where to look for this particular part?
thanks

 

I've heard from Porsche and audi shop owners that connecting the battery cables and leaving them connected overnight is the way to drain ALL of the capacitors in the electrical system. Myth or true I don't know; but whenever a 15 second reset or 15 minute reset doesn't work for me, I try the overnight/24 hours. I've had mixed results, and haven't documented them, so just try and maybe it could help in this case, maybe not.

One of the mechanics worked at a Porsche dealership before opening his shop, and said it was almost an unwritten policy they had at the dealership to treat incoming cars with the overnight cable reset before pulling codes and starting work the next day

I don't know if this procedure resets STFT and LTFT on these particular vehicles.

 

The "keep alive memory" reset should be sufficient for resetting LTFT, You don't need VIDA to do it.

 

Thanks for all advices above.
small update - replaced front o2 sensor as my mechanic was insisting it was the cause. Upon replacing, car actually WAS FINE for about 30kms, didnt miss a beat. For small moment I was happy but didnt last long - it started misfiring again on accelerating, then on normal cruising and then it started misfiring constantly. At this moment car misfires all the time - idle, rev, driving - no matter. Misfire 3rd cylinder all the time, occasionally showing misfire on other but cyl3 seem to be constant/main issue.
Per advices, i did the following:

• reset battery
• reflashed ECU (last good configuration map from Hilton , that I was driving on for last 4 years)
• checked fuel pressure - seem normal, reported apx 400 on idle etc
• swapped coil 3 with coil 2 - didnt make difference, misfire on cyl3 still persist.
• no other codes showing up except for misfiring

At this point im left with only 2 more options - swap/check plugs and injectors, will have it done on Tuesday as im not technically minded to do so myself. Not sure if compression test is needed as car wouldnt drive well for 30kms if it was compression problem, isnt it?
If there is anything else you may think of - appreciate advice.
Cheers

 

Have you checked the wiring to the #3 coil? Have you confirmed spark on #3? It doesn't sound like a fuel problem to me, but put a noid light on #3 injector to confirm that it's firing properly.

Do you have access to a scanner that can record data while driving? That's going to offer a lot more useful information than just testing at idle.

 

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Do you have access to a scanner that can record data while driving? That's going to offer a lot more useful information than just testing at idle.

Yes I have Vida+DiCe and OBD scanner always handy in car so I can take various readouts, problem is im not usually sure what data to log and how to interpret them. For example when diagnosing above, what info would you display when driving to log the behaviour? As example I took photo of the data i logged few days ago (on standstill) with something that i think is useful info but not sure if it would tell me anything? As u probably know I can only log 10items at one time

** also update on my case** - left the car with my mech yesterday again and he replaced all 5sparks - car started to work OK back again and so far after 120kms driven there is no faults coming back (not to jinx it). Car also feels nippy and drives very good in general but I havent checked the boost logs etc yet, at the moment its just "butt dyno". Im constantly worried misfire will come back thinking that sparks were the outcome not the cause, but will see in next few days.
thanks all for help in this case.

 

So what I am hearing is that touching the exhaust manifold will release a curse upon the sparkplugs?

 

By all means of black magic - yes!
Although if you want more scientific approach, the explanation of driving with loose manifold causing ECU to go berserk with a&f ratio and causing plugs to go bad after months of driving like that, is more probable :>

either this or OEM plugs that had 15k miles only were faulty.

choose your pick