Stalling and low idle
09-02-2004, 06:32 PM
#1
Race Car
Thread Starter
Stalling and low idle
I mentioned on another thread that my idle is a little low (about 790rpm). In addition, when I tried to start the car this morning (hadn't used it for 2 days) it initially refused to start - turned over but didn't catch. I had to put my foot on the accelerator, then it started. Idle was still low - even from cold.
Even when the idle is low there is no hunting - its rock steady, just a bit low.
When I finished work, car started and idled fine - but whe moving, it stalled each time I pushed the clutch in, until it had been running for a few minutes and warmed up slightly. No idle hunting - revs just dropped straight to zero.
I did notice that by the time I got home (15 mins / 7 miles) the idle was back where it should be.
I'm thinking that the one thing that could cause all of these symptoms is the temperature sensor. Does this sound likely - or any other suggestions?
Even when the idle is low there is no hunting - its rock steady, just a bit low.
When I finished work, car started and idled fine - but whe moving, it stalled each time I pushed the clutch in, until it had been running for a few minutes and warmed up slightly. No idle hunting - revs just dropped straight to zero.
I did notice that by the time I got home (15 mins / 7 miles) the idle was back where it should be.
I'm thinking that the one thing that could cause all of these symptoms is the temperature sensor. Does this sound likely - or any other suggestions?
09-03-2004, 01:20 AM
#2
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Dave,
One thing I learned about these cars, is when you have stalling problems, it could be many things. I would start with the DME relay which controls the fuel pump (as well as other things). You may want to perform a DME reset, which requires you to disconnect battery, wait 20 minutes or so, and then reconnect. Then immediately going for a "sprited drive" (using all gears and accelerating through the changes).
When I had a similar problem, i.e. stalling problems, it turned out to be oil on the air side or overfill of oil which worked its way into the air flow meter. You can do a quick check by removing the air filter assembly and placing your hand (tight spot) in the air flow meter and looking for oil. If you find it, you should clean out the air flow meter and ISV with brake cleaner which will clean and leave no residue.
If this does not work, I recommend you invest in Adrian Streather's Porsche 911 Ethusiast's Companion (Bentley Publishers) which is dedicated to the 964 and gives excellence guidance for troubleshooting. Do this before you spend much money on troubleshooting.
Good Luck,
One thing I learned about these cars, is when you have stalling problems, it could be many things. I would start with the DME relay which controls the fuel pump (as well as other things). You may want to perform a DME reset, which requires you to disconnect battery, wait 20 minutes or so, and then reconnect. Then immediately going for a "sprited drive" (using all gears and accelerating through the changes).
When I had a similar problem, i.e. stalling problems, it turned out to be oil on the air side or overfill of oil which worked its way into the air flow meter. You can do a quick check by removing the air filter assembly and placing your hand (tight spot) in the air flow meter and looking for oil. If you find it, you should clean out the air flow meter and ISV with brake cleaner which will clean and leave no residue.
If this does not work, I recommend you invest in Adrian Streather's Porsche 911 Ethusiast's Companion (Bentley Publishers) which is dedicated to the 964 and gives excellence guidance for troubleshooting. Do this before you spend much money on troubleshooting.
Good Luck,
09-03-2004, 09:01 AM
#4
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Dave,
If you get a chance, after dark start the car up, and spray the distributor caps with a mist of water. I found I was getting arcing at the bottom of the wire ends on the distributor caps. I had to put some silicone based di-electric grease around the bottom of each plug wire, and this cleared up an idle problem I was having.
Unfortunately, if you find arcing along the wires, you will need new wires......... (I had this problem when I put new rotors,caps and plugs in the car)
-Eric
If you get a chance, after dark start the car up, and spray the distributor caps with a mist of water. I found I was getting arcing at the bottom of the wire ends on the distributor caps. I had to put some silicone based di-electric grease around the bottom of each plug wire, and this cleared up an idle problem I was having.
Unfortunately, if you find arcing along the wires, you will need new wires......... (I had this problem when I put new rotors,caps and plugs in the car)
-Eric
09-03-2004, 03:38 PM
#5
Race Car
Thread Starter
I think I found the problem..... stupid mechanic......
I took a quick look in the engine bay this afternoon. When I cleaned the ISV and air flow sensor the other day I was in a bit of a rush. Somehow I'd managed to twist one of the pipes to the ISV (think I must have fitted the pipe to the ISV before clamping the ISV in place and fitting the electrical plug). This meant it was almost twisted closed.
Untwisted it, and so far the idle seems to be back to it's normal speed (and steady). Since the idle only dropped since I did my "fixes" last week, I think that was probably the problem.
I took a quick look in the engine bay this afternoon. When I cleaned the ISV and air flow sensor the other day I was in a bit of a rush. Somehow I'd managed to twist one of the pipes to the ISV (think I must have fitted the pipe to the ISV before clamping the ISV in place and fitting the electrical plug). This meant it was almost twisted closed.
Untwisted it, and so far the idle seems to be back to it's normal speed (and steady). Since the idle only dropped since I did my "fixes" last week, I think that was probably the problem.
