What do you all make of this?.....Help needed

[mcandmar]

Is that unique to the 7A? I don't find a listing for that function on the AAN (ABY/ADU) ECU (pins 7/55, 25/55 and 26/55):

http://forums.quattroworld.com/s4s6/msgs/21009.phtml

It is, or should i say unique to the Hitachi fuel injection. You have a CO mixture pot on the MAF unit, and an idle bleed valve on the throttle body. Basically you pop a fuse into the fuel pump relay to set it up, then set the base idle speed using the screw on the throttle body (800 or 850rpms i think), then the CO using the pot on the MAF. Then you go around in circles doing it over and over again as they effect each other. Many hours later you get it roughly within spec

As far as i know V6 engines use the same system.

[Kliminati456]

haha @ 5hitachi

If it were a timing issue wouldn't the problem be constant, meaning it wouldn't come and go but rather always be acting in that way. I did have a nasty little distributor rattle a few months ago and tightened the t belt which seemed to help but maybe fooked the little plastic gear?

I cleared all the codes last night and started it up today with no issues at all. checked the codes and nothing came up. played with the idle screw and its where it should be right around 850-900 rpm. This would make me think it is either the maf or throttle potentiometer on its way out. So I guess when it happens again whatever code pops up will be the culprit. Here's a vid of the startup with no issues....

http://www.youtube.com/watch?v=funKdHULgm8

edit:and now its back, still no code though

[mcandmar]

Nothing worse than intermittent faults. But i agree if the timing was off it would wrong all the time, no harm in checking all the same.

Have you tested the throttle body yet? I posted some info here from the Bentley manual trying to help another forum member, http://www.s2forum.com/forum/showthr...5&highlight=7a worth checking just to rule it out. From reading that thread again it might be an idea to borrow another MAF and see if thats where the issue is.

@UrS4boy: more info from the Bentley manual on setting Idle Speed and CO. http://www.s2forum.com/forum/showpos...9&postcount=18

[Kliminati456]

Did some testing per Bentley with a multimeter and got these results....

Throttle pot
Supply volt testing (harness) Should be close to approx. 5 volts
Terminal 2-4 = 5.12 volts
Terminal 3-4 = 3.47 volts

Electrical checking (resistance in pot)
Terminal 1-3 = 5310 ohms (Bentley says 3000 to 6500 ohms)
Terminal 2-3 = 3750 ohms (Bentley says 3000 to 6500 ohms)
Terminal 2-3 Fully open throttle = 210 ohms (Bentley says 0 to 600 ohms)

20v.org has a test thats the same but tells you to test terminal 2 to 4 instead of 1 to 3 which Bentley does not say to do hmmm???
Terminal 2-4 = 0 ohms (20v.org says 3000 to 6500 ohms)


MAF Supply volt testing (harness)
Terminal 3-Ground = 11.77 volts (Bentley says approx. 12 volts)
Terminal 3-2 = 11.72 volts (Bentley says approx. 12 volts)
Terminal 2-4 = 8.39 volts (Bentley says approx. 8 volts)

MAF function testing (harness connected to MAF volts, rubber pulled back)
Terminal 2-4 = 3.92 volts (Bentley says 1-7.5 volts)
Terminal 1-2 = .69 volts (Bentley says .3-1.1 volts)
Terminal 1-2 car running idle to 4000rpm =1.65-2.44 volts (Bentley says voltage must vary between 1.5-3.4 volts)

So it seems I have some voltage that seems to be too low so it could be grounds or the ecu. If 20v.org is correct in their test the the pot is shot.

[UrS4boy]

Turns out that your 054133154C throttle position potentiometer is unique to the NM and 7A engines. That said, there could still be good used ones out there in the breakers' yards.

[Kliminati456]

Cleared all codes and swapped in new(used) maf sensor , 2232 air mass sensor and 2242 CO potentiometer

Tried cleaning both old and new maf sensor, also adjusted both maf potentiometer screws 25 turns each direction in increments of 5 turns while on car No combination worked. 2232 and 2242 came up on both.

Now car wont start anymore and the intake makes a slight squeal sound and white puffs of smoke occasionally come out of the intake cone filter. Supply voltage in harness is correct.

G62 coolant sensor connection seems good.

Confused and frustrated

[Kliminati456]

Problem still continues to plague car after warm up mode...

No codes
New 02 sensor
Swapped maf
Swapped tps
Checked g62 coolant sensor which matches correct resistance values
Cleaned/tightened all grounds
Checked/fixed all vacuum leaks
car has Bosch injectors with good o rings

[Kliminati456]

Problem has been solved. So it was ignition related, I was really convinced it had to be something with the air intake from the codes thrown up.Just really odd how in warm up mode car was fine but once at operating temp problem started.
Fouled spark plugs, not to mention they were completely wrong ones. Bosch FR8DS? First time I actually checked them since I bought the car last year Put in a nice new set of Bosch F6DTC. Also the distributor cap and rotor were disgusting inside covered with some black slime so replaced both of those with new as well. God its nice to have my car back and its running better than before from all the other things I fixed while searching for the problem. Its been torture looking at my car sitting in the garage with brand new KWs on it that ive only been able to use once. Im going for a drive lol

[WabTheKing]

think theres a seal on the dizzy shaft that stops oil from the the cyl head/dizzy drive entering the rotor arm secta or as you would say sectoooor