My car has been running very rich, and misfiring. My mechanics have checked the compression, timing, throttle body, and fuel pump, and can’t seem to find the problem (they said it runs just like a car with a cracked throttle body, but there’s no crack). does anyone have any suggestions on where else to look???
One item you might look at is the fuel pressure regulator. If the diaphragm springs a leak, fuel will be sent into the intake manifold. For diagnosis, remove the vacuum line from the fuel regulator at the intake manifold and see if there is liquid gas in the line. If there is gasoline there, replace the fuel pressure regulator.
Hope That Helps.
Thank you! I will have them look into that!
Well, the fuel pressure regulator checked out ok; so I’m back to square one. Any other suggestions?
Does your vehicle have Electronic Controlled Suspension (ECS)? I have a '92 Dodge Stealth (3 liter DOHC) that developed a ‘miss’ condition a few years ago. After much hair-pulling and gnashing of teeth by the mechanics at Firestone, they found a knowledge-base article pointing to the ECS controller. Un-plugging the ECS controller (and eventually replacing it) solved the problem.
By the way, google ‘3SX PERFORMANCE’ for a parts supplier that specializes in the Stealth/3000 GT.
No, my car does not have an ECS, thank you for the parts supplier info though!
See if you can get the readings on long and short term fuel trim. This may lead you into the O2 sensors or something else. Is the MIL on ?
I’m going to go out on a limb. The fuel will be metered based on either a mass airflow sensor or manifold absolute pressure sensor in combination with a temp sensor, and, finally, the oxygen sensor. The crank or cam speed sensor counts too, but if that were bad it probably wouldn’t run at all.
When the engine temps sensor tells the ECU that the engine is cold, the ECU bypasses the osygen sensor signal to allow the engine to run rich. If the temp sensor is broken and the ECU doesn’t know the engine is warm, it’ll continually run rich and may not even throw a code.
The MAF or MAP sensor if defective can also cause rich running.
An eroded or stuck or sticky injector can as well…or, if it’s multiport the entire set of injectors could be eroded. Erosion can lalow too much fuel into the cylinders.
Again, I’m offering a few wild guesses based on what’s already been checked.
Thank you, wild educated guesses are exactly what I need! I’ll look into that!
well, after 2 months, my regular mechanics gave up. so i had it towed to another place and they found that the timing belt had jumped a couple teeth (within a week). I’m friends with the owner of my regular mechanics shop, and when I told him, he was NOT happy at the mechanic who he’d assigned to work on it!