wow... What happened to your car for not having the harness secured??

 

After I had R&R's the intake thing ran fine. Then slowly, over time (a month or two) I would randomly loose power. It got progressively worse. I thought I had cooked the harness from when I had the engine out. I still replaced the harness, but upon removing the old harness I found one of those little ****ing bolts back there was loose to the touch. I guess I didn't tourque them down. Lesson learned.

 

This gets me thinking about how I came to have a spare LH.

But, that's not the point.

Andy, your intake is powder coated? Painted? Did you also coat/paint the water bridge?

 

sounds like perhaps a bad MAF...have you unplugged it when its running to see if there is any change? i can see the crap the exhasut has blown onto the street. I dont think a Temp II sensor will make any difference to the way the car runs once its well warmed up/hot.

how about the ISV..does the car run with it unplugged?

 

i can't unplug it. cannot reach down there. It is definitely working though. The MAF is John Speake's with about 1000 miles on it. When I first had this problem I bought his thinking it would fix it.

 

This really sounds like the same problem I was having with my old 87 S4. My rebuilt MAF from 928intl was BAD and my TPS sensor was on the way out.

FYI- at that time (07) 928intl was sourcing MAF rebuilds from John Speake and another company (mine was from the other company) so make sure yours really is from John.

 

Some possibilites. Do not let it defeat you. These are the fixes for my 32V car problems the last few weeks with intermittent cut-out and no-start.

Ground cable from battery -- simply temp. replace with a $7 one from an autoparts store.

CE panel individual wires in front plugs / press in using backprobe method. This was biggest problem. They weren't locked in with the bottom panel slide lock, plus, some of the top lock tabs got broken off. Loose plugs, loose wires within plugs.

Take a hard look at the 14 pin connector with a light and magnifying glass. Remove wire covers. Resolder them if any questions. Also, the male/females can be loose if aggressively cleaned and damaged in the process.

Ground screws at back L and R of bellhousing area under airbox (as suggested above).

New relays; clean fuse tab corrosion with a metal nail file. Were very corroded.

Dsconnect O2 sensor.


Now it runs. Was inches away from buying new LH and MAF.

 

How do I get to the 14 pin connector. Where is it on an S4?

 

Is he referring to the 14 pin connector under the (oft missing) rain cover on the passenger side mid engine bay. Just by the cross-brace.


Isn't the connector plug (black round connector about 1 inch long) for the O2 sensor normally behind/below the fuse/relay panel inside the car?

 

Dude!? C'mon....

 

No ****.

 

Forgot about that thing in the passenger side of the engine bay under that shiny black cover

Who knows, maybe there is a ton of corrosion under there that could be causing it. All I know is that the car runs great until the LH adapts after an X amount of miles.

 

So you are saying it always runs good right after the battery has been disconnected for a few minutes? Then disconnect the battery and the O2 sensor, then reconnect the battery and see if it continues to drive good.

Dan
'91 928GT S/C 475hp/460lb.ft

 

Does anyone have a 14-pin connector diagram? I think I just realized some minor electrical gremlins may all intertwine with this same issue and it could all be 14-pin connector related. For example, my tach bounces still starting it up and I already have a new crank sensor.

 

The LH isn't "adapting", the injection system is trying to run in "closed loop". Just disconnect the 02 sensor (as a few of us have told you already ) and see what happens.