I spoke with a mobile mechanic yesterday . These are the things he suggested looking into.
He said the map sensor may be faulty and causing the extreme rich running issue that I'm now having. He said the map sensor could also be related to the original idle issue that I was having but its now completely faulty, causing the rich running problem, on top of idle issues.
The part number on my map sensor is 261-230-075. I tried to cross that number over with my local auto parts stores but unsuccessful. I contacted General Motors who gave me a crossover GM part number of 12568929, but they said the number is not showing as a part available anymore. I was able to find the part ending in 075 online, so I guess I'll order one.
The mechanic also suggested a new IAC. I did originally replace the IAC when I was originally troubleshooting for the idle issue I was having. Once I replace the IAC with a new unit, it didn't seem to make any difference at all, so I sent back the new one back and put my original one back in.
He questioned me about the temperature swings that I'm seeing on my temp gauge on the dash. He said we need to verify whether or not I'm truly getting this type of temperature swings.
If you remember in my earlier posts, the temp would rise up to around 175*, then when the thermostat would open, the temps would drop down, bottoming out on the gauge which only starts at 100 degrees.
The idle issue I was originally having fell between 160 and 175 degrees. Anything below 160 on the dash guage & the motor would run smooth. Anything over 160 & we had idle issues.
He said we need to shoot the thermostat housing near the 2 prong connector brass temp sensor with an IR gun and verify what kind of temperature swings I'm getting throughout the temperature cycle. He also suggested shooting both exhaust logs to see if I'm getting similar temperature swings there. He said if we are truly getting large temperature swings, we need to figure that out first, because the ECM will be throwing a temper tantrum, not knowing what the heck it needs to do.
He didn't think my engine temperatures on the dash gauge should be dropping below 140 at any point since I have a brand new 150* Volvo Penta thermostat installed (which is the thermostat called for my engine).
I intend to replace the following items which were swapped over from my original motor:
•IAC
•TEMP SENSOR in thermostat housing which has the 2 prong connector.
•TPS
•EXHAUST MANIFOLD SENSORS(1 sensor in each log)
The thermostat, distributor cap, rotor, spark plug wires, and crank sensor have all been replaced. I also have a brand new set of spark plugs waiting to be installed but don't want to do this until I figure out the running rich issue.
Your thoughts on the machanics suggestions?
Anything else you can think of which I should swap out for new other than the part I listed? I hate throwing part's at the motor but at least, this way, I can hopefully eliminate them as being an issue.