Carrera Not Starting Or Driving Smoothly.

[jyl]

I'm starting to have driveability problems with my 1989 3.2L Carrera.

I'll try to describe the symptoms:
1. When starting the car, the starter will crank normally, but it can take 5 seconds for the engine to start, and then it will die immediately unless I rev it up to around 3,000 rpm and hold it there for a while.
2. When driving, if the revs are below about 3,000 rpm, the engine is prone to stall.
3. When the engine is running at medium to high rpm (say 3,000-4,000 rpm) and I shift to neutral and let off the gas, the rpms often will not drop quickly to idle. Instead, the rpms will stay medium to high for a while, before eventually dropping.
4. As long as the rpms are medium to high, the car seems to drive normally, with normal power.

Symptom 3 has been slowly developing over the past couple of months. Symptom 1 and 2 just emerged this morning. They left my wife stranded a few blocks from home. I walked down there, got the car started, and drove it home with one stall along the way.

I should add that it has been raining hard for a day and the car has been sitting outside, if that makes a difference.

My first question is, what should I check? I've read a few older threads on 3.2L driveability, and I see mention of sensors at the flywheel, DME, and DME relay. I can swap out the DME relay but am not sure what to do with the other things.

My second question is, should I just take the car into a mechanic, or call Mobileworks? It's the holidays, this is my only car, if this is likely to turn into a multi-week troubleshooting process I might choose the checkbook solution.

[nhromyak]

'89s should not have the CHT sensor problem.

The DME relay should be replaced just to check. (You have a spare - right?)

Check the grounds around #1 cylinder intake runner and on the body for corrosion. Also check the grounds on the body where these go.

It sounds more like a vacuum leak somewhere.

Check the tightness of the intake runners (these use an allen).
Check ALL hoses with a flashlight and mirror behind and around the back of the "main" intake throttle plate. I forget what this is called-sorry. These seem to crack and become hard to detect that they cracked because they are so far in the back behind everything.

Could also be the ISV and or it's hoses too.

Good luck. If nothing else, I bumped you back up!

[ZOA NOM]

Sounds like a bad Air Flow Meter. Search on some AFM threads. You might also have a combination of problems, including the AFM, the ICV, and maybe your Throttle Position Switch.

[don911]

I had similar issues when my air fuel mixture was messed up due to a wire coming off at the Air Meter.
Also check the distributor and make sure no moisture is getting in there.

[ZOA NOM]

Easy things to check:

Idle Control Valve - remove and shoot some cleaner in there. it should move freely back and forth inside. It should hum slightly with car idling.

Dizzy - eliminate moisture, clean contacts, confirm continuity to all 6 plugs

AFM - resistance check at 4-pin connector on the front; smooth resistance change between pins 2&3 (the middle two) when manually moving the vane inside. This is easiest with the AFM removed. If you see erratic jumps in resistance as the vane is moved slowly, the pickup resistor inside has worn spots on it that ruin the quality of the signal sent to the DME, causing all sort of trouble. Do a search on AFM problems, and you should find a thread with how to remedy the problem without sending it off or replacing it.


Check this thread

[jyl]

Hmm, now the car starts fine (symptom 1 disappeared) and seems to hold idle (symptom 2 reduced or gone). Weird.

My wife is convinced the car hates her, well I'd hate someone who burned out my parking brake by leaving it on all day too. Grrr, since I recently redid the brakes and am not keen to rebleed them.

I will start working through the suggestions above. Thanks!

I did disconnect the O2 sensor as a first step, no dramatic/obvious change to behaviour.

[WydRyd]

Check for vacuum leaks. I have all sorts of drivability and idling issues and I found huge vacuum leaks at the #2 and #3 intake runners. The problem is inlet manifold gaskets. It's common for these to dry up, shrink and get blown out or sucked into the engine, which creates a vacuum leak. This causes the engine to idle poorly, run lean on those cylinders and you'll notice a big drop in power, response and popping/backfiring through the intake.

I'm about to tackle mine tonight

Good luck.