Car won't pass E-test - high everything at 25 mph and I've been over the intake a dozen times looking for leaks. No codes set, slightly wavering idle, biggest problem is at about 2000-2500 rpms when it has the symptoms of running rich. Plugs are carboned up a little with cylinder 1 being the worst and cylinder 4 being the best. Car starts first time but is gutless for the 1st minute or so (feels like it's running lean) until the o2 sensor kicks in. I've been over all the other normal tune up/ fuel injection stuff testing and swapping parts until I'm blue in the face. Exhaust system is almost brand new front to back ( done by previous owner). So, does this sound like it could be an exhaust leak?

Thanks,

Ron

93 245
93 944

OK, no exhaust leak - took it to a muffler shop and they checked it over with a stethoscope. This is good news and bad news - I'm glad it wasn't a cracked or leaking exhaust manifold. It was raining last night and the car ran much worse, so there's my new clue - something electrical affected by moisture.

ROn

several things come to mind:

1 failing o2 sensor
2 for the moisture problem replace all really old plug wires
3. if ALL the spark plug wires and coil wire are decent remove them and insert di electric grease between all wires and what they connect to
4. remove and clean all engine grounds and use di electric grease on re connection

i think your oxygen sensor is causing the e problems

do not forget after you replace the sensor or verify it is absolutely sound to disconnect the neg battery cable for a few minutes and allow all CURRENT running instructions in the ecu to delete. you want the engine to re learn.

It is certainly staring to sound like o2 sensor, although I don't get the wet weather thing. The sensor looks fairly new and responds to a forced rich and lean and seems to vary across appropriate voltage range. The plug and coil wires are new and greased. I will go over the grounds again. I'm going to examine the o2 sensor wires to see if there's any chance they are flaky.

Thanks for your response, this has been quite an exercise in troubleshooting. What would really like to see is the control logic algorithm for the Regina fuel injection system so I can stop guessing what inputs are active when.

I'm surprised I'm not getting any codes here..

Ron

i believe i have the volvo green manual wiring diagram for that year and model in pdf format

if you like i can upload and give you the link where to get it

as to your specific question that info i do not have

I would love to see that info from the green book as well. If you could post it somewhere for all to see, I'm sure there are a number of us who'd appreciate it.

thanks,
john

That would be great, thanks.

Ron

i need areal email address from you to send this large file

I sent an E-mail to your posted E-mail - did you get it?

Thanks,

Ron