LuminaASG Posted October 30, 2002 Report Posted October 30, 2002 This is a bit long.. sorry.. I am getting real shit gas mileage in my lumina and am getting very near 10mpg.. Yeah I just hooked up my air/fuel gauge to my front O2 sensor and seen that my car is almost always running on the rich side... Crusing down the street at a steady speed = Rich. Give it a little gas = rich.. The only time it's lean is if say I'm in park and I rev it up, once the idle is falling back down it reads real lean.. I just don't know, if it's not lean or rich its back between the 2 very frequently, I just can't get a happy medium.. Oh and now the idle is sometime's rough and dies out every so often.. If anyone could tell me what to test to try and start to get down to the bottom of this it'd be great. Fuel pressure at Rail about 40psi which is about right for cadillac (41-49psi) so a little under. New O2's and injectors. now they are Ford motor sport injectors but they were cheap for the set, only 19lb's an hr and Bruce Nunnally put em in his seville with no problems so I think there ok.. Air temp sensor also fairly new.... I'd read out the codes in the ECM but I have no way of doing it, paperclip won't work cause the MIL lamp isn't connected.. I'd love to be able to access the computer with a scanner or some sort of laptop software but don't know where to get the cable or the right software from... Suggestions on this would be great cause then I could really get to the bottom of this.. Quote
gpse3200 Posted October 30, 2002 Report Posted October 30, 2002 Its either the MAP circuit or the Coolant temp circuit. Your rough idle suggets a bad vacuum reading, but high fuel comsumption indicates a slewed sensor towards a cold reading, thus the engine using more fuel. One or the other. Quote
LuminaASG Posted October 30, 2002 Author Report Posted October 30, 2002 Well I'll check on both the map and the CTS sensor.. I don't think it's the CTS cause the cooling fans still come on at the right time, but it's a 3 wire circuit so maybe on of the leads inside went bad... As for the rough idle I think it's from me toying with the Idle speed control sensor.. I was adjusting it a bit and not too long after I got this.. As for vacuum it certainly could be that.. I have almost all lines just capped off other than the MAP sensor line, and the trans module line.. The car has no purge canister so I just have to cap them.. Is there anyway one of the ones capped is supposed to be sucking in air say from the canister??? No idea the EGR line is also capped off but I wouldn't think that'd make it run real rich but maybe???? My main thing is that I'd love to know what the computer is thinking about it just no way of knowing... I have a copy of Diacom but not certain on how to make the cable for it... http://www.obd-onboarddiagnostics.com seems to make nice software but it's $315 with the cable.... I think that's a bit pricey!!! Quote
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