1986 944 fault codes
04-11-2009, 10:46 PM
#1
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1986 944 fault codes
2 questions
1 Does my 86 944 have K Jetronic, L Jetronic or Motronic?
2 Is there a way to get fault codes to diagnos a rough idle problem?
1 Does my 86 944 have K Jetronic, L Jetronic or Motronic?
2 Is there a way to get fault codes to diagnos a rough idle problem?
04-12-2009, 02:50 PM
#2
Three Wheelin'
1. L-Jetronic
2. There are no "codes" in this unit. You need Volume I, section 24 of the Factory Service Manual and you'll be all set on diagnostics. Maybe some parts of Volume IV.
Search around, you'll find a PDF of it. But rough idle isn't likely to be something the DME is going to tell you about.
You can try to disable the ISV and see if your idle is better after adjusting it. It's possible your ISV is dirty/not working. It is also possible if not probably that your fuel injectors could use some cleaning, that you have a vacuum leak somewhere, or that your FPR is going bad. Search for "rough idle" here for literally hundreds of posts on the various thing is could be, most with troubleshooting and repair information.
2. There are no "codes" in this unit. You need Volume I, section 24 of the Factory Service Manual and you'll be all set on diagnostics. Maybe some parts of Volume IV.
Search around, you'll find a PDF of it. But rough idle isn't likely to be something the DME is going to tell you about.
You can try to disable the ISV and see if your idle is better after adjusting it. It's possible your ISV is dirty/not working. It is also possible if not probably that your fuel injectors could use some cleaning, that you have a vacuum leak somewhere, or that your FPR is going bad. Search for "rough idle" here for literally hundreds of posts on the various thing is could be, most with troubleshooting and repair information.
04-12-2009, 03:35 PM
#3
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Location: Medford NJ 86 944 NA
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Rough idle most likely culprits (IMHO):
1) Vacuum leaks. Replace ALL the vacuum hoses and clean your ISV. Check the J-Boot for cracks. Tighten up the vacuum connections.
2) Fuel Injector/fuel flow problmes. Change your fuel filter and run and double dose of fuel injectorcleaner through the tank. Check you FPR
3) Ignition wires and/or cap and rotor. Open up the hood in the dark and have someone gun the engine a few times while you visually inspect the entire length of the ignition wires for sparks. If you see little sparks flying around, replace the wires. Remove and inspect the cap and rotor for cracks and carbon tracing. Clean the cap and rotor contact points.
jmd_forest
1) Vacuum leaks. Replace ALL the vacuum hoses and clean your ISV. Check the J-Boot for cracks. Tighten up the vacuum connections.
2) Fuel Injector/fuel flow problmes. Change your fuel filter and run and double dose of fuel injectorcleaner through the tank. Check you FPR
3) Ignition wires and/or cap and rotor. Open up the hood in the dark and have someone gun the engine a few times while you visually inspect the entire length of the ignition wires for sparks. If you see little sparks flying around, replace the wires. Remove and inspect the cap and rotor for cracks and carbon tracing. Clean the cap and rotor contact points.
jmd_forest
04-12-2009, 06:01 PM
#4
Burning Brakes
probably air leak on inlet but worth checking ICV
DME self diagnosis with fault codes and testing started with the 944S 1988 model onwards. See section 03 in the 944 workshop manual
I found this on the All experts site
To test the ISV.
There is a Test Plug located near the Fuse/Relay box.
Engine warm. You jump pins B & C.
Adjust the idle with largest screw on Throttle Body.
Remove jumper.
Take a short drive and see if problem is resolved.
There is a procedure to attempt to clean the ISV as well.
Otherwise its most likely a vacuum leak and there are plenty
of sources or points to check, especially where a hose connects
to a component the end of the hose tends to harden if not break
in time on a 22 year old car.
If you can find someone with a "smoke machine" you can find
leaks quickly.
DME self diagnosis with fault codes and testing started with the 944S 1988 model onwards. See section 03 in the 944 workshop manual
I found this on the All experts site
To test the ISV.
There is a Test Plug located near the Fuse/Relay box.
Engine warm. You jump pins B & C.
Adjust the idle with largest screw on Throttle Body.
Remove jumper.
Take a short drive and see if problem is resolved.
There is a procedure to attempt to clean the ISV as well.
Otherwise its most likely a vacuum leak and there are plenty
of sources or points to check, especially where a hose connects
to a component the end of the hose tends to harden if not break
in time on a 22 year old car.
If you can find someone with a "smoke machine" you can find
leaks quickly.
Last edited by peanut; 04-12-2009 at 06:18 PM.
