Crazy Fox Fix for rich running 50 Feature Mustang
I wanted to share this just in case anybody ever had the same issue pop up.
Last fall I posted a fix to a strong gas smell in my exhaust. It was running so rich that white smoke was coming out of the tailpipes. New O2 sensors took care of it. Or so I thought.
Well, I has just finished up installing a new radiator, springs, and shocks/struts and all four corners. I made an appointment to get an alignment and state inspection. I started up the car that morning and my rich running/smokey fuel exhaust problem was back. I decided to let the shop take a look at it since I already had an appointment. Well, two hours of labor later they had no idea what was causing it. So, I told them to not do anything else and that I would pick it up and figure it out.
Well, it took me a week. Just yesterday I finally tracked down the root cause of the problem. A plug read lead me to the fact that the #1 cylinder was getting doused with fuel. If fact so much that my fresh oil change was just wasted due to leak down past the rings. (The shop did a compression test and everything was fine). I did some signal chasing and took some resistance measurements at the injectors. Nothing looked bad per se, but the number one injector harness plug looked different from a resistance standpoint than the others. So I pulled the computer out and sure enough it was the same weird measurement at its terminals with the harness off. I figure I've got nothing to lose so I take the computer apart and discover two problems:
1. The electrolytic capacitors are bad.
2. A glob of grease from the factory was lodged between the ground leg and the ouput leg of the #1 injector driver.
I replaced the capacitors with spares I had from another project and cleaned the grease off the transistor. I put it all back together and problem solved.
I hope this helps somebody else - or at least gives everybody a laugh!
Last fall I posted a fix to a strong gas smell in my exhaust. It was running so rich that white smoke was coming out of the tailpipes. New O2 sensors took care of it. Or so I thought.
Well, I has just finished up installing a new radiator, springs, and shocks/struts and all four corners. I made an appointment to get an alignment and state inspection. I started up the car that morning and my rich running/smokey fuel exhaust problem was back. I decided to let the shop take a look at it since I already had an appointment. Well, two hours of labor later they had no idea what was causing it. So, I told them to not do anything else and that I would pick it up and figure it out.
Well, it took me a week. Just yesterday I finally tracked down the root cause of the problem. A plug read lead me to the fact that the #1 cylinder was getting doused with fuel. If fact so much that my fresh oil change was just wasted due to leak down past the rings. (The shop did a compression test and everything was fine). I did some signal chasing and took some resistance measurements at the injectors. Nothing looked bad per se, but the number one injector harness plug looked different from a resistance standpoint than the others. So I pulled the computer out and sure enough it was the same weird measurement at its terminals with the harness off. I figure I've got nothing to lose so I take the computer apart and discover two problems:
1. The electrolytic capacitors are bad.
2. A glob of grease from the factory was lodged between the ground leg and the ouput leg of the #1 injector driver.
I replaced the capacitors with spares I had from another project and cleaned the grease off the transistor. I put it all back together and problem solved.
I hope this helps somebody else - or at least gives everybody a laugh!