7a hesitation, looking for wisdom

[varia]

I have this weird problem with my CQ 20v 7A
My CQ hesitates sometimes, like 1 or 2 cylinder are not running, CEL came up few times.
Pulled the codes, thats what i got:

Code: Select all

Tuesday,14,May,2013,10:37:12:24117
VCDS Version: Release 11.11.5

                Address 01: Engine       Labels: None
Control Module Part Number: 893 906 266 D
  Component and/or Version: MOTOR       PMC 10
           Software Coding: 
            Work Shop Code:   
                      VCID: 254BF493BFBF333072A
5 Faults Found:

01249 - Fuel Injector for Cylinder 1 (N30) 
            31-10 - Open or Short to Ground - Intermittent
01250 - Fuel Injector for Cylinder 2 (N31) 
            31-10 - Open or Short to Ground - Intermittent
01251 - Fuel Injector for Cylinder 3 (N32) 
            31-10 - Open or Short to Ground - Intermittent
01252 - Fuel Injector for Cylinder 4 (N33) 
            31-10 - Open or Short to Ground - Intermittent
01253 - Fuel Injector for Cylinder 5 (N83) 
            31-10 - Open or Short to Ground - Intermittent

Readiness: N/A

Ive changed the fuel pump relay and it was ok for two months, but its back again so I changed the relay one more time (brand new) new spark plugs, spark wires, distributor cap, rotor, fuel filter, fuel pump and new coolant temp sensor (back of the cylinder head)

Still the same, when its warmed up (ie fans kicks in temperature) often check engine light is on, seems one cylinder is not running, blue smoke.
few seconds later everything is back to normal.

Planning to change/check: wires, connector for injectors, MAF but other then that, im clueless.
Any ideas, advice?
Thank you
Chris

[scubadave]

Check compression, fuel pressure, strength of ignition spark. Those cheap threaded gap-able spark checkers give a good idea of strength over length of gap. Check the spark plugs for tracking (carbon burn marks/tracks down along the porcelain) if present, wires are the issue. Use dielectric grease in the wires to help that from happening. Timing belt alignment, timing chain for slop. Bad chain slop usually throws a knock sensor code and causes the computer to pull timing all while valve timing is off. Could also be ignition module.

[varia]

Check compression, fuel pressure, strength of ignition spark. Those cheap threaded gap-able spark checkers give a good idea of strength over length of gap. Check the spark plugs for tracking (carbon burn marks/tracks down along the porcelain) if present, wires are the issue. Use dielectric grease in the wires to help that from happening. Timing belt alignment, timing chain for slop. Bad chain slop usually throws a knock sensor code and causes the computer to pull timing all while valve timing is off. Could also be ignition module.

All injector are swapped, bypass checked.
Compression are: 1-200, 2-197, 3-195, 4-190, 5-187, No leak.

Its not oily, but dry powdery black carbon residue, to rich mixture, not burned properly.

My question is, why not burned properly:
Not good spark (strength, timing, etc)
or
Too much fuel injected, can an injector over spray?

Thanks
Chris

[scubadave]

Check compression, fuel pressure, strength of ignition spark. Those cheap threaded gap-able spark checkers give a good idea of strength over length of gap. Check the spark plugs for tracking (carbon burn marks/tracks down along the porcelain) if present, wires are the issue. Use dielectric grease in the wires to help that from happening. Timing belt alignment, timing chain for slop. Bad chain slop usually throws a knock sensor code and causes the computer to pull timing all while valve timing is off. Could also be ignition module.

All injector are swapped, bypass checked.
Compression are: 1-200, 2-197, 3-195, 4-190, 5-187, No leak.

Its not oily, but dry powdery black carbon residue, to rich mixture, not burned properly.

My question is, why not burned properly:
Not good spark (strength, timing, etc)
or
Too much fuel injected, can an injector over spray?

Thanks
Chris

What I meant about carbon tracking was along the outside of the plug. Like the spark from the wires would rather go around the outside and find ground instead of go through the plug like its supposed to. Seems like you have spark issues to me. Maybe your spark is going weak. This is the tool I was talking about

http://www.autozone.com/autozone/access ... rget=shelf

See if it will jump a large gap to see if you have a weak coil. With this you can also see how bright the spark is.

Start with the basics. If you need another coil and a ignition module to try, i have an extra from when I did my turbo conversion. LMK.

After working on cars for a long time, I learned to recognize spark misfire. Too bad I cant just go for a ride real quick and help you pinpoint it.

[varia]

Really appreciate your help, i will do it tomorrow first thing!
Thank you
Chris

[varia]

I never used this before, so let me know if i didnt do it right:

#1 http://quattro4life.com/download/1.mp4 13mb

#4 http://quattro4life.com/download/4.mp4 23mb

[scubadave]

looks strong to me. not a coil problem. is the injection stock, or 034 kit? stock, do they ohm out to spec? have you had them cleaned/ checked? how often do yo experience this problem? all the time, or very sparratic? going out on a limb, did you check all your grounds? computer gets its grounds off the engine, and injectors are switched on the ground side, not the pos side. like to see the injector waveform pattern as the isssue occures. you dont have access to an oscilloscope do you?

[varia]

Looks like i found the problem, #4 injector ground wire goes to GND somewhere other then ecu.
But it only happens (mostly) when the car is warm/hot.

I dont know if the ECU INJ4 OUT goes bad, could it burn the wire?
I had an other ecu, plugged that in, pulled a new ground wire from #4 Injector to ECU D9, now runs like a champ.
I didnt want to put back the old ecu yet. Tomorrow, I will do more testing in heavy traffic., we shall see

Would be much easier to find if this cave man version ecu would throw a code for the grounded injector only not for all the injector, it was very misleading. (I did a test, removed the #1 Injector connector, stil got the code for all 5.)

Thank you very much!
Chris

[scubadave]

hey, glad you found the problem...most likely. hope I helped. like knowing I still have something to contribute to the community. And, knowing I still have the skillz and knowledge base to be effective.