Idle completely stops then restarts
08-12-2003, 10:13 PM
#1
1st Gear
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Idle completely stops then restarts
I have a 1983 944 that was in very bad shape when I got it, but now is getting a lot of attention. When I have a car I want it running right.
Recently we have this odd problem: it runs fine, but the idle cuts out. It goes in a 5 or 6 second cycle, repeating over and over: the idle slowly rises to about 1100, then the car just dies. It suddenly restarts and the idle starts its slow rise again. Very frustrating.
Twice the car would not start at all but later it did, and back to the odd idle.
I tried spraying carb cleaner in various places to see if there is a vacuum leak but the changing idle makes it hard to tell. I sprayed it a lot around the top of the fuel injectors, all over - and then the idle did suddenly rise, but maybe there is some natural suction there anyway.
I am not a mechanic so I can putter but can't get too much into it. I have a Haynes and tried a few things. The injector cables for example all have 12V on one side, and I checked a few more things.
I am hoping that someone had this exact problem. If its a mysterious vacuum leak, how to find it?
I have more 944 questions relating to performance and all that, but first I have to get it running well!
My email is Kevin@Testkits.com.
Thanks,
Kevin
Recently we have this odd problem: it runs fine, but the idle cuts out. It goes in a 5 or 6 second cycle, repeating over and over: the idle slowly rises to about 1100, then the car just dies. It suddenly restarts and the idle starts its slow rise again. Very frustrating.
Twice the car would not start at all but later it did, and back to the odd idle.
I tried spraying carb cleaner in various places to see if there is a vacuum leak but the changing idle makes it hard to tell. I sprayed it a lot around the top of the fuel injectors, all over - and then the idle did suddenly rise, but maybe there is some natural suction there anyway.
I am not a mechanic so I can putter but can't get too much into it. I have a Haynes and tried a few things. The injector cables for example all have 12V on one side, and I checked a few more things.
I am hoping that someone had this exact problem. If its a mysterious vacuum leak, how to find it?
I have more 944 questions relating to performance and all that, but first I have to get it running well!
My email is Kevin@Testkits.com.
Thanks,
Kevin
08-12-2003, 10:38 PM
#2
Nerd Herder
Rennlist Member
Rennlist Member
Wandering or surging idle is a classic case of a loose/ broken or open vacuum line somewhere. Don spray stuff into or around it- it may be so slight you cant see the vacuum pulling it in- and not all vacuum goes to intake- Carb cleaner can harm some components- like the brake booster. besides its flammable and you sure dont want a fire.
You can do it the hard way (remove each vacuum line and test)
or a better way (replace every vacuum line)
I suggest the latter at the parts are cheap, and you couls spend weeks tracking down several small leaks.
BTW- it "sounds" like the 1/8" vacuum line going to the brake booster..
My .02
You can do it the hard way (remove each vacuum line and test)
or a better way (replace every vacuum line)
I suggest the latter at the parts are cheap, and you couls spend weeks tracking down several small leaks.
BTW- it "sounds" like the 1/8" vacuum line going to the brake booster..
My .02