Hello Fellow Volvoheads! First time poster, long time lurker here!

I posted this on Turbobricks, but I figured I'd see if anyone here has had the same issue.

I have a 1991 245 B230f stock, LH2.4. It is running rich, but not "pig rich" as it was when I first bought it. In an effort to A. Not be an idiot and B. not anger the brick gods by saying "look at me I know part numbers, what will this do!!!" I have realized that throwing parts at what I think is the problem without any concrete proof isn't going to get me anywhere...

So....

I replaced what I knew for a fact had gone bad: Fuel Pressure Regulator (there was fuel in the vacuum line) and the ECU (I had a California ECU, the car has an EGR Delete and the previous owner never swapped in a 49 State unit) and it is idling much better, not throwing random 02 and TPS codes or throwing black soot out the talipipe, yay progress! Fuel Economy has also increased from an abysmal 13.5 Average MPG to 19.2 Average MPG. However two codes persist, 113 - Fuel Injectors and 224- Coolant Temp Sensor Signal. I think I have found the culprit!

To address Fuel Injectors I have 4 good tested Injectors from an LH2.4 '89 245 (that I got for under $30 for all 4 yay) that are being sent to Mr. Injector for refurbishment. But addressing the coolant temp sensor signal issues I am less confident about. I suspect the wiring where the coolant temp sensor plugs into has gone bad. I'll admit I know nothing about engine wiring and have a hookup for electrical work.

My question to my fellow 240 owners is, has anyone else experienced this problem and this particular code and was able to address it without having to throw in a whole new wiring harness? I know these OBD1 Codes are vague in nature and serve as mere clues, so I was just curious if any other B230f owners on here have experienced this, before I jump to any conclusions and mis-diagnose problems that aren't there.

Any insight is much appreciated!

 

You probably have leaking fuel injectors and they are leaking to the point where the fuel trim can no longer keep them at the correct flow rate.

 

To fix your rich running condition you will have to address the engine coolant temperature sensor as if it has failed (as the code indicates), the ECU will think the engine is cold and enrich the mixture. Also, check for any leaks in the air tube between the AMM and the throttle body. Any leaks will let in unmetered air that the the ECU may detect as a lean condition. Any exhaust leaks between the engine and the O2 sensor will likewise be interpreted by the ECU as a lean condition and will try to enrich the mixture. All of these items will cause reduced gas mileage.