This first part is for knowledge in case anyone else is having a similar problem.
So I have been trying to diagnose an intermittent stutter for the last 2 months. It only occurs when the engine is warm, or warming up after about 5 minutes of driving. It's been painful. I replaced the coil, plugs, intake gaskets, cleaned the contacts on the c191 connector, temp sensor, all body grounds. I have a new cap and rotor and plug wires.
I also have a Miller MAF so I cleaned that with MAF cleaner.
I decided to adjust the valves thinking that they could possibly be too tight and and once it was hot the CTE's causing an issue... A long shot, i know. All of these things did absolutely nothing for the problem.
Finally I thought O2 sensor but I didn't see any CEL so I couldn't diagnose it with the stomp test.
I disconnected the battery and shorted the positive and negative leads (not the battery terminals!) to hopefully clear the ECU of any memory which I'm not sure it even stores.
Then I disconnected the O2 sensor from the harness. The O2 sensor is relatively new, about 4 years old. But the plug on the harness is original and the pins were quite corroded. I cleaned them up and and plugged it back in, and reconnected the battery. The car ran differently, not correctly, but differently. Idle was much higher - about 1100 when warm. While traveling on a flat road at constant RPM, and engine up to operating temps the CEL came on. When I gave it gas, it went off. Same thing while idling at a stop light. I got home and let it idle to get the CEL to come on then shut down the car to hold the code. Stomp test revealed a 1222 code. Excessively lean or rich. high idle suggests rich and probing the sense wires on the O2 leads revealed .85V which translates into rich running.
So, I can throw out low fuel supply problems as I have an excess of fuel.
My next step is to replace the injectors.
So here are my specs:
Miller MAF
IE headers, full custom mandrel bent exhaust
Bimmerheads 272 Billet cam
I've been reading that the M50b25 injectors are a good replacement option. Does anybody feel strongly about a certain design over another?
I'm not saying that this is definitely the problem. I will update this thread once I replace the injectors.
This has probably been covered ad nauseam but I couldn't find anything really conclusive, especially when considering modified internal engine components.
Thanks,
Pete
So I have been trying to diagnose an intermittent stutter for the last 2 months. It only occurs when the engine is warm, or warming up after about 5 minutes of driving. It's been painful. I replaced the coil, plugs, intake gaskets, cleaned the contacts on the c191 connector, temp sensor, all body grounds. I have a new cap and rotor and plug wires.
I also have a Miller MAF so I cleaned that with MAF cleaner.
I decided to adjust the valves thinking that they could possibly be too tight and and once it was hot the CTE's causing an issue... A long shot, i know. All of these things did absolutely nothing for the problem.
Finally I thought O2 sensor but I didn't see any CEL so I couldn't diagnose it with the stomp test.
I disconnected the battery and shorted the positive and negative leads (not the battery terminals!) to hopefully clear the ECU of any memory which I'm not sure it even stores.
Then I disconnected the O2 sensor from the harness. The O2 sensor is relatively new, about 4 years old. But the plug on the harness is original and the pins were quite corroded. I cleaned them up and and plugged it back in, and reconnected the battery. The car ran differently, not correctly, but differently. Idle was much higher - about 1100 when warm. While traveling on a flat road at constant RPM, and engine up to operating temps the CEL came on. When I gave it gas, it went off. Same thing while idling at a stop light. I got home and let it idle to get the CEL to come on then shut down the car to hold the code. Stomp test revealed a 1222 code. Excessively lean or rich. high idle suggests rich and probing the sense wires on the O2 leads revealed .85V which translates into rich running.
So, I can throw out low fuel supply problems as I have an excess of fuel.
My next step is to replace the injectors.
So here are my specs:
Miller MAF
IE headers, full custom mandrel bent exhaust
Bimmerheads 272 Billet cam
I've been reading that the M50b25 injectors are a good replacement option. Does anybody feel strongly about a certain design over another?
I'm not saying that this is definitely the problem. I will update this thread once I replace the injectors.
This has probably been covered ad nauseam but I couldn't find anything really conclusive, especially when considering modified internal engine components.
Thanks,
Pete
Comment