1990 Mustang GT - Supercharged w/rebuilt 306 stock E7 heads, forged bottom end, degreed stock cam, Kenne Bell 2.1
Car is running smoother in closed loop now. Each time I restart it after being warm, it runs like crap until it goes back into closed loop. Found a weak HEGO on the drivers side and now it is switching pretty good at idle and off-idle. Before it was only switching at idle. Other than the Hego's what is different in open loop as compared to closed loop??? I would like to find what other bugs are in this car.
Background: Head gasket issue ... got head shaved and new gasket ... more combustion leaks into cooling system within a week. Pulled engine out and had block machined and decked, had heads checked again .. machinist said both surfaces were flat. Put it back together with 9333 PT1's. Found a bad lifter and replaced. Found a bad (brand new) MSD TFI module that caused engine to miss at 2,500 rpm .. replaced with used Ford TFI module but idled rough. Replaced MSD distributor with rebuilt distributor (Cardone) to test. Idled better intially then found O2 sensor problem mentioned above. Now it idles better in closed loop than open loop. When I restart it, it runs rough until the Hego's get hot again .. then it idles pretty good. I have had KOER codes 12 and 91 and still do now. I also get a Code 96 fuel monitor code. Had these codes for a year and can NOT get rid of them no matter what I do. I have checked over and over for vacuum leaks but do not find anything significant. Found leak around dipstick and block and dipstick to tube and fixed. Found a little leakage around throttle shaft and at EGR pintle shaft (but it idle the valve is closed so this should not affect idle) ... and when idleing, I have grabbed the throttle shaft and rocked it but no change whatsoever in idle. IAC is working and slows engine down progressively when stepping on the gas as well as turning on accessories. Vacuum is around 16-16.5 on this new engine which concerns me and about 14 at idle in drive. When I'm getting into the throttle, vacuum drops normally but seems to drop even more at times even to the supercharger beginning to work or EGR open up or carbon canister valve opens ... engine just seems to be too low then on vacuum. When I do KOER test I warm it up til its hot but it seems as though the test throws it into open loop somehow and I notice neither oxygen sensor registers and then the Code 91 is registered and I think the rest of the test is stopped at this point. Soon as the test is over and I restart the car, and let it run a minute, I can feel and hear the engine go into closed loop and it runs much better again and the HEGO's start switching once again. Or am I under the wrong assumption that they should not be switching in open loop because they are not. After restarting a hot engine each time they do not register then I lightly depress the pedal a few times and then the start registering and switching between 0 and 0.7. The passenger side usually switches between 0.2 and 0.7 and the new drivers side sensor is switching between 0 and 0.7 so it appears the drivers side could be a hair lean. But when it goes to open loop on restarts it just runs like a** until I apparently cross that threshold point and the HEGO's start registering. Does anyone have any ideas what is causing any of this because I have been through this car more than several times ... and I have found many problems but am pretty much stuck now and have to put it through emissions shortly. And when its running in open loop, the fumes are pretty bad unlike when in closed loop ... something just isn't right. Any help would be greatly appreciated ... this was OLD months ago ... worked on it everyday this Summer and now Summer has passed! Thanks!
Car is running smoother in closed loop now. Each time I restart it after being warm, it runs like crap until it goes back into closed loop. Found a weak HEGO on the drivers side and now it is switching pretty good at idle and off-idle. Before it was only switching at idle. Other than the Hego's what is different in open loop as compared to closed loop??? I would like to find what other bugs are in this car.
Background: Head gasket issue ... got head shaved and new gasket ... more combustion leaks into cooling system within a week. Pulled engine out and had block machined and decked, had heads checked again .. machinist said both surfaces were flat. Put it back together with 9333 PT1's. Found a bad lifter and replaced. Found a bad (brand new) MSD TFI module that caused engine to miss at 2,500 rpm .. replaced with used Ford TFI module but idled rough. Replaced MSD distributor with rebuilt distributor (Cardone) to test. Idled better intially then found O2 sensor problem mentioned above. Now it idles better in closed loop than open loop. When I restart it, it runs rough until the Hego's get hot again .. then it idles pretty good. I have had KOER codes 12 and 91 and still do now. I also get a Code 96 fuel monitor code. Had these codes for a year and can NOT get rid of them no matter what I do. I have checked over and over for vacuum leaks but do not find anything significant. Found leak around dipstick and block and dipstick to tube and fixed. Found a little leakage around throttle shaft and at EGR pintle shaft (but it idle the valve is closed so this should not affect idle) ... and when idleing, I have grabbed the throttle shaft and rocked it but no change whatsoever in idle. IAC is working and slows engine down progressively when stepping on the gas as well as turning on accessories. Vacuum is around 16-16.5 on this new engine which concerns me and about 14 at idle in drive. When I'm getting into the throttle, vacuum drops normally but seems to drop even more at times even to the supercharger beginning to work or EGR open up or carbon canister valve opens ... engine just seems to be too low then on vacuum. When I do KOER test I warm it up til its hot but it seems as though the test throws it into open loop somehow and I notice neither oxygen sensor registers and then the Code 91 is registered and I think the rest of the test is stopped at this point. Soon as the test is over and I restart the car, and let it run a minute, I can feel and hear the engine go into closed loop and it runs much better again and the HEGO's start switching once again. Or am I under the wrong assumption that they should not be switching in open loop because they are not. After restarting a hot engine each time they do not register then I lightly depress the pedal a few times and then the start registering and switching between 0 and 0.7. The passenger side usually switches between 0.2 and 0.7 and the new drivers side sensor is switching between 0 and 0.7 so it appears the drivers side could be a hair lean. But when it goes to open loop on restarts it just runs like a** until I apparently cross that threshold point and the HEGO's start registering. Does anyone have any ideas what is causing any of this because I have been through this car more than several times ... and I have found many problems but am pretty much stuck now and have to put it through emissions shortly. And when its running in open loop, the fumes are pretty bad unlike when in closed loop ... something just isn't right. Any help would be greatly appreciated ... this was OLD months ago ... worked on it everyday this Summer and now Summer has passed! Thanks!
