riceboyler
12-20-2005, 11:54 PM
OK, car is an 87 Shelby CSX I've had since February of this year, has a recently (35K ago) rebuilt motor with JE Pistons, Mopar Perf. LM, JoeP MBC set to 15 psi, 1G DSM BOV. About a month ago, I replaced the O2 wiring harness, as the previous one had rubbed against my power steering pulley and worn the insulation off. About 3 days after that, it got relatively cold (lows in the low-mid 20s) and the car started running richer than crap and sucking down gas like crazy. For a few weeks prior to that, the car had been running rich (you could smell it in the exhaust), but no noticeable effect on the gas mileage.
Since then, the car has been running very cold (never gets above 3 bars on the temp gauge), pig rich (according to the A/F meter and the smell, and the mpgs) and idling very low when cold.
I have replaced the coolant temp sensor as of this weekend, which didn't help the gauge at all, but the heater got much warmer. I put a can of SeaFoam in the tank and in the throttle body, but that didn't help the idle issues. Now, I question the O2 sensor and think it may be bad, but it's reading that the car is running rich constantly. It does bounce, but not at cruise, and at cruising speeds (3K RPM, part throttle) reads 8 bars on the A/F (Intellitronix) gauge. Odd thing is that if I hit boost, it moves back down to normal A/F levels until I get back out of boost.
I haven't had a chance to check fuel pressure yet, but I did pull plugs, and they were all very dark brown - black, so it's not just one injector or anything. I'm think that the FPR has gone bad, and is now throwing too much fuel in for the computer to handle.
One further note. I have an FM475 cam (came in the car) and I'm only seeing 13-15psi of vacuum at idle (when it idles correctly after it's warmed up). That's all I've ever seen at idle since I got the car, and I figured it was normal for the cam, but I'm beginning to wonder. What would normal vacuum be at idle for that cam?
Thanks in advance. This is my first post here, and I want to say a big thanks to Ken and Frank for presenting a great alternative. Hopefully the crap from the other forum will stay over there and not try to poison this place. Good luck guys, and thanks.
Since then, the car has been running very cold (never gets above 3 bars on the temp gauge), pig rich (according to the A/F meter and the smell, and the mpgs) and idling very low when cold.
I have replaced the coolant temp sensor as of this weekend, which didn't help the gauge at all, but the heater got much warmer. I put a can of SeaFoam in the tank and in the throttle body, but that didn't help the idle issues. Now, I question the O2 sensor and think it may be bad, but it's reading that the car is running rich constantly. It does bounce, but not at cruise, and at cruising speeds (3K RPM, part throttle) reads 8 bars on the A/F (Intellitronix) gauge. Odd thing is that if I hit boost, it moves back down to normal A/F levels until I get back out of boost.
I haven't had a chance to check fuel pressure yet, but I did pull plugs, and they were all very dark brown - black, so it's not just one injector or anything. I'm think that the FPR has gone bad, and is now throwing too much fuel in for the computer to handle.
One further note. I have an FM475 cam (came in the car) and I'm only seeing 13-15psi of vacuum at idle (when it idles correctly after it's warmed up). That's all I've ever seen at idle since I got the car, and I figured it was normal for the cam, but I'm beginning to wonder. What would normal vacuum be at idle for that cam?
Thanks in advance. This is my first post here, and I want to say a big thanks to Ken and Frank for presenting a great alternative. Hopefully the crap from the other forum will stay over there and not try to poison this place. Good luck guys, and thanks.