Occassional "Check Engine" light and rough running upon startup
01-19-2005, 05:04 AM
#16
Rennlist Member
Originally Posted by fpena944
In any case as far as I know the ignition module has not been replaced. But don't you think the issue would be a bit more intermittent if that needed to be changed?
What have you replaced so far? FPR and Damper? Mine is still stuttering on and off. Pushing the gas pedal hard makes it go away, but it takes a second or so. Injectors sounds premature on a relatively low miles car like yours, IMHO, but it's possible I guess.
01-19-2005, 08:18 AM
#17
Got Nothin'
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It sounds like the ISV. It plays havoc with a cold engine when not operating correctly. My cold start problems several years ago were corrected by replacing it.
01-19-2005, 08:26 AM
#18
Rennlist Member
Originally Posted by PeteL
It sounds like the ISV. It plays havoc with a cold engine when not operating correctly. My cold start problems several years ago were corrected by replacing it.
01-19-2005, 09:21 AM
#19
Three Wheelin'
Fpena:
I didn't read this post before today, so I hope this is going to help.
The first thing that caught my attention was your mention of a "Check Engine Light." If your gage cluster has an actual "Check Engine Light", then you must have an OBD (On Board Diagnostics) enabled DME, which means you should be able to "pull the codes" (retrieve the internally stored fault codes) to get a line on what is wrong.
To pull the fault codes, turn the ignition on but do not start the engine. Hold the accelerator pedal to the floor (WOT) for 3 to 5 seconds.
After the Check Engine light goes out and comes back on, release the accelerator. This on off period indicates the serf-diagnostic system is preparing to output the diagnostic codes.
The next Check Engine on off period will represent the first fault code stored. Record the fault code and again depress and hold the accelerator pedal at WOT for 3 to 5 seconds. Release the pedal and record the second code.
Continue to hold and release the accelerator until code 1000 is displayed, indication end of output.
Some fault codes:
1000 End of output
1111 DME power <10 volts
1112 Idle Speed Switch, short in ground circuit
1113 Full throttle Switch, short in ground circuit
1114 Engine Temp Sensor, open circuit
1121 Airflow Sensor, signal not plausible
1123 O2 Sensor, mixture is rich
1124 O2 Sensor, open, shorted, or faulty sensor
1125 Intake Air Temp Sensor, open/short
1131 Knock Sensor 1, signal not plausible
1132 Knock Sensor 2, signal not plausible
1133 Knock Regulation, knock computer faulty
1134 Hall Effect Sensor, open/short
1141 DME faulty
1151-1154 Fuel injector 1-4, open/short
1500 System Operating Normally, No faults stored
NOTE: Some fault codes cannot be displayed via the Check Engine light. These codes must be retrieved by using the Porsche scan tool.
To clear the fault codes, turn the ignition on and hold the accelerator pedal at WOT for more than 12 seconds. The Check Engine light will go out briefly at 3, 7, and 10 second intervals to indicate that fault code memory has been cleared.
(The preceeding information was taken from the Haynes TechBook (10205), "Automotive Computer Codes & Electronic Engine Management Systems," ISBN 1 56392 108 1, pages 7A-24/25, and 7B-52/53.)
Second, since you have an OBD DME, when ever you make a change to the engine (like installing a new FPR or replacing a temp sensor) you need to "reset" the DME. Disconnecting the DME from the harness will clear all fault codes and adaptive settings.
Third, if you want to get a second set of eyes on the problem, just let me know, I'd be more than happy to help.
I didn't read this post before today, so I hope this is going to help.
The first thing that caught my attention was your mention of a "Check Engine Light." If your gage cluster has an actual "Check Engine Light", then you must have an OBD (On Board Diagnostics) enabled DME, which means you should be able to "pull the codes" (retrieve the internally stored fault codes) to get a line on what is wrong.
To pull the fault codes, turn the ignition on but do not start the engine. Hold the accelerator pedal to the floor (WOT) for 3 to 5 seconds.
After the Check Engine light goes out and comes back on, release the accelerator. This on off period indicates the serf-diagnostic system is preparing to output the diagnostic codes.
The next Check Engine on off period will represent the first fault code stored. Record the fault code and again depress and hold the accelerator pedal at WOT for 3 to 5 seconds. Release the pedal and record the second code.
Continue to hold and release the accelerator until code 1000 is displayed, indication end of output.
Some fault codes:
1000 End of output
1111 DME power <10 volts
1112 Idle Speed Switch, short in ground circuit
1113 Full throttle Switch, short in ground circuit
1114 Engine Temp Sensor, open circuit
1121 Airflow Sensor, signal not plausible
1123 O2 Sensor, mixture is rich
1124 O2 Sensor, open, shorted, or faulty sensor
1125 Intake Air Temp Sensor, open/short
1131 Knock Sensor 1, signal not plausible
1132 Knock Sensor 2, signal not plausible
1133 Knock Regulation, knock computer faulty
1134 Hall Effect Sensor, open/short
1141 DME faulty
1151-1154 Fuel injector 1-4, open/short
1500 System Operating Normally, No faults stored
NOTE: Some fault codes cannot be displayed via the Check Engine light. These codes must be retrieved by using the Porsche scan tool.
To clear the fault codes, turn the ignition on and hold the accelerator pedal at WOT for more than 12 seconds. The Check Engine light will go out briefly at 3, 7, and 10 second intervals to indicate that fault code memory has been cleared.
(The preceeding information was taken from the Haynes TechBook (10205), "Automotive Computer Codes & Electronic Engine Management Systems," ISBN 1 56392 108 1, pages 7A-24/25, and 7B-52/53.)
Second, since you have an OBD DME, when ever you make a change to the engine (like installing a new FPR or replacing a temp sensor) you need to "reset" the DME. Disconnecting the DME from the harness will clear all fault codes and adaptive settings.
Third, if you want to get a second set of eyes on the problem, just let me know, I'd be more than happy to help.
01-19-2005, 10:37 AM
#21
Addict
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Thread Starter
Cliff,
Wow, thanks for the very thorough troubleshooting technique!
Now if I do not have the Porsche scan tool how can I tell what fault codes are displaying? Would the fault codes cause the "Check engine" light to flash on and off? Or is there a display somewhere under my dash where I can merely retrieve the codes?
If this works it'll be such an asset to help troubleshooting problems...Thanks again!
Wow, thanks for the very thorough troubleshooting technique!
Now if I do not have the Porsche scan tool how can I tell what fault codes are displaying? Would the fault codes cause the "Check engine" light to flash on and off? Or is there a display somewhere under my dash where I can merely retrieve the codes?
If this works it'll be such an asset to help troubleshooting problems...Thanks again!
01-19-2005, 11:39 AM
#22
Three Wheelin'
Without the Porsche scan tool the only way to display fault codes is via the flashing of the Check Engine light.
When you are retrieving the codes the Check engine light will flash on and off. For example, the light will flash once, pause, flash one or more times, pause, flash one or more times, and so on.
You can find a more detailed listing of the fault codes in the Workshop manual.
When you are retrieving the codes the Check engine light will flash on and off. For example, the light will flash once, pause, flash one or more times, pause, flash one or more times, and so on.
You can find a more detailed listing of the fault codes in the Workshop manual.
01-29-2005, 01:20 PM
#23
Addict
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Thread Starter
Originally Posted by Charlotte944
Without the Porsche scan tool the only way to display fault codes is via the flashing of the Check Engine light.
When you are retrieving the codes the Check engine light will flash on and off. For example, the light will flash once, pause, flash one or more times, pause, flash one or more times, and so on.
You can find a more detailed listing of the fault codes in the Workshop manual.
When you are retrieving the codes the Check engine light will flash on and off. For example, the light will flash once, pause, flash one or more times, pause, flash one or more times, and so on.
You can find a more detailed listing of the fault codes in the Workshop manual.
The procedure you posted came back with a code of one of the fuel injectors shorting out. I reset the car by disconnecting the DME and figured I'd try it again. Now the car seems to be idling better and hasn't had the problem come back up again. But if it does, looks like I'll be sending the injectors in for an overhaul.
Thanks again!
