Engine problems HELP!
02-25-2002, 09:02 PM
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Engine problems HELP!
90 Audi 90 5 cill. FWD automatic. About 130K
At idile the engine dosen't run fine.
Sound like doesn't have gas, or like one of the cillinders dosen't work. It dosen't have power.
But after 1500RPM everiting seems fine.
I checed the pressure on the cillinders, and it's fine (~180 an all)
I changed the O2 sensor, the catalitic convertor, the spark plugs, knock sensor (cracked)and the fuel filter.
Any body have any ideea what else coud be wrong?
Valves? How can I check if all the cillinders are working?
Thanks
At idile the engine dosen't run fine.
Sound like doesn't have gas, or like one of the cillinders dosen't work. It dosen't have power.
But after 1500RPM everiting seems fine.
I checed the pressure on the cillinders, and it's fine (~180 an all)
I changed the O2 sensor, the catalitic convertor, the spark plugs, knock sensor (cracked)and the fuel filter.
Any body have any ideea what else coud be wrong?
Valves? How can I check if all the cillinders are working?
Thanks
02-25-2002, 10:01 PM
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A few things you might look at or try. (kinda long)
Check the spark plug wires with a digital multimeter. If they have a resistance of over 20 ohms, then they are bad. Mine are around 4 ohms each. Don't forget the coil wire.
Also check the spark plugs. If they seem fine visually, check the gap (if applicable), and test the resistance from the inner electrode to the connector. While you're at it, double check your distributer cap and rotor. Look for corrosion (a sign of arching).
Do you have any codes stored? If your knock sensor was bad, you might have been running in 'limp mode' and your timing may be skewed. Check your stored codes (search this forum for a procedure). Maybe try disconnecting the battery for a few minutes to reset codes after you've checked them if it still won't run right.
You might also try running some fuel injector cleaner.
If you are worried about a cylinder not firing, try this:
With the engine running, remove the wire from the number one spark plug and see if the RPM of the engine drops. If it does, that cylinder is working. Do this for each spark plug, one at a time and listen/look for an RPM drop. If your engine is unaffected by the removal of a spark plug wire, that cylinder is not working and that is where you should focus your attention. Keep in mind, you might get zapped a few times doing this. Be careful.
Good luck!
Also check the spark plugs. If they seem fine visually, check the gap (if applicable), and test the resistance from the inner electrode to the connector. While you're at it, double check your distributer cap and rotor. Look for corrosion (a sign of arching).
Do you have any codes stored? If your knock sensor was bad, you might have been running in 'limp mode' and your timing may be skewed. Check your stored codes (search this forum for a procedure). Maybe try disconnecting the battery for a few minutes to reset codes after you've checked them if it still won't run right.
You might also try running some fuel injector cleaner.
If you are worried about a cylinder not firing, try this:
With the engine running, remove the wire from the number one spark plug and see if the RPM of the engine drops. If it does, that cylinder is working. Do this for each spark plug, one at a time and listen/look for an RPM drop. If your engine is unaffected by the removal of a spark plug wire, that cylinder is not working and that is where you should focus your attention. Keep in mind, you might get zapped a few times doing this. Be careful.
Good luck!
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