Jon89le Posted August 17, 2003 Report Share Posted August 17, 2003 Alright, well it started the other day when i was driving and the car kept cutting out on me. I was cruising on a back road and all fo a sudden it started jerking like when you hit the rev limiter and fuel gets cut. Eventually the car shut off. So i pull over and it will only start if i flutter with the gas pedal and runs like crap, like its going to stall. After the motor cools however it runs fine, but then after it warms up (after exactly 3-4 min everytime) it will just shut off without a hit of stall and same problem, wont start unless i mess with the throttle. I ran my scan tool and it came up with a code 23 and code 53. So i checked my EGRs vacuums and they seem fine. All the sensors are fairly new (only 10,000 miles on them) and i just replaced the IAC now. Can anyone help? Code 23 mentions the MAT but what is that? Is that the sensor that goes in the airbox? I dont know what else to try. If anyone can give me ANY help id really appreciate it. Thanks... Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted August 17, 2003 Report Share Posted August 17, 2003 If I was to guess from scratch, sounds like a fuel related (duh). But, I would start with checking fuel pressure; it may be the damn fuel pump. Especially when after it warm ups and you're gettting vapor lock. Try some simple tests and see where that gets you. And yes, the MAT or more known as the IAT is in the airbox and used for spark timing. - Erik Quote Link to comment Share on other sites More sharing options...
Slade901 Posted August 17, 2003 Report Share Posted August 17, 2003 Yep.. Check that Manifold Air Temperature (MAT) or Intake Air Temperature (IAT) sensor/wires on the air box as Erik said. Have you tried to convert to a cone air filter and forgot to connect the MAT/IAT along the new cone filter piping? With regards to the EGR, you may have to remove the EGR and clean the passage ways on the EGR. Try to create a remote switch for the radiator fan and let it turn on once the car is running and leave the radiator fan turn on all the time and see if the car still dies around 3-4 minutes. That way you can further isolate and narrow down the problem. Quote Link to comment Share on other sites More sharing options...
Brian P Posted August 17, 2003 Report Share Posted August 17, 2003 reset the computer and re-learn the idle Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted August 17, 2003 Report Share Posted August 17, 2003 Mine did that mess when the crank sensor wire was shorting out to the block Robby Quote Link to comment Share on other sites More sharing options...
Jon89le Posted August 17, 2003 Author Report Share Posted August 17, 2003 Well i cant do the idle relearn since the car wont stay on long enough for that,lol. That IAT sensor is new but ill have to check it out. I can double check all the other wires but im getting a code for those two things so im guessing its those or an input/output sensor sensor related to the two codes. And the computer doesnt have a cone on it, just plain 'ol air box... One of you guys mentioned vapor lock, is that whats happening to me? Would that cause the motor to just immediately shut off? How is that caused and hows it related to the pump? Im asking because ive never heard about it before? If it was the fuel pump, dont those things just go? Quote Link to comment Share on other sites More sharing options...
brian89gp Posted August 17, 2003 Report Share Posted August 17, 2003 How new is your o2 sensor? 3-4 minutes sounds like the time it takes to go into closed loop. Quote Link to comment Share on other sites More sharing options...
89oldscutlass Posted August 17, 2003 Report Share Posted August 17, 2003 We had a Lumina last week come in to the garage doing the same thing we checked the fuel presure and found that it was fine until the car warmed up and at that point the fuel pressure dropped and and the car would be idling and just die.We put a new fuel pump on it and a new filter and it took care of the problem.Check your fuel pressure first and then try a new fuel filter thats the cheapest route to go. Quote Link to comment Share on other sites More sharing options...
Jon89le Posted August 19, 2003 Author Report Share Posted August 19, 2003 How can i check my fuel pressure? The only way i know of is pressing the shrader valve but that wont give me a direct reading,lol. And if there is a specific reading or range for the pressure, what is it? The O2 sensor was put in when i did the car, so about 7months ago. BTW, now im getting a code 23 as before but now a 43, no more 53. I checked my book and 43 is related to spark control but i know my ICM is good because it just got replaced about 2months ago and when it went, it just went with no warning, and coil packs wouldnt start working fine again once the car cooled off, so what the hell?!?! A few of the "diagnostic trees" in my service manual lead to the ECM. Could the entire computer be bad? Quote Link to comment Share on other sites More sharing options...
Lee Posted August 19, 2003 Report Share Posted August 19, 2003 I wouldn't rule out the crankshaft sensor yet. Your codes could be setting simply from trying to keep it running. When my c. sensor went out (both times, two sensors) it died right then and now but would run 5 min, (it was winter) after being completely cold. It never set a code that I knew of. The second time I just had it towed and they fixed it. Quote Link to comment Share on other sites More sharing options...
89oldscutlass Posted August 20, 2003 Report Share Posted August 20, 2003 Sorry it took me a while to answer your question about your fuel pressure.We have been covered up at the garage. On 2.8s and 3.1s your fuel pressure should be 41 to 47psi durring normal operation.As far as checking your fuel pressure we have a universal gauge set at the garage to test all fuel injected cars and trucks. On the 2.8s and 3.1s the valve is on the intake and is made like a car tire valve stem sorta.My brother said that you could go buy a fuel pressure gauge to mount in your car to keep tabs on your fuel pressure. Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted August 20, 2003 Report Share Posted August 20, 2003 you should be able to "borrow" a fuel pressure gauge from autozone on the loan a' tool thing...just pay the deposit for it and then get your money back after returning it....I don't believe fuel pressure gauges are that expensive if I'm thinking right..I'm probably going to invest in one sometime soon just to have. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted August 20, 2003 Report Share Posted August 20, 2003 you should be able to "borrow" a fuel pressure gauge from autozone on the loan a' tool thing...just pay the deposit for it and then get your money back after returning it....I don't believe fuel pressure gauges are that expensive if I'm thinking right..I'm probably going to invest in one sometime soon just to have. All the autozones around me dont rent/loan out anything. I think a Fuel Pressure Guage is like $20 On another note, I still think its the crank sensor Robby Quote Link to comment Share on other sites More sharing options...
god910 Posted August 20, 2003 Report Share Posted August 20, 2003 Please don't mount a fuel pressure gauge IN the car. The ones designed to be mounted IN the car are $189.99 @ Jegs. Quote Link to comment Share on other sites More sharing options...
Jon89le Posted August 20, 2003 Author Report Share Posted August 20, 2003 Well i tryed a new ECM last night and it worked fine. It stood on for 30min and that was with shutting it off twice in between. The cars idle is even smoother than before now. In a little bit im going to drive around and test it out so ill let you guys know how it goes. I think im still going to test that fuel pressure thing out though. Just to make sure... Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted August 20, 2003 Report Share Posted August 20, 2003 It sounds like classic symptoms of a bad ECM. I hope that fixed it for you. Quote Link to comment Share on other sites More sharing options...
1990cutsupreme3.1sedan Posted August 22, 2003 Report Share Posted August 22, 2003 yea mine did the same thing just not as often. i would drive around and almost at random the car would cut out and die. sometimes it would start right up afterwards other times i would have to wait. i had this guy read the codes and the ecm was reading a temp of like 270 or something crazy. turns out the ecm was failing which i guess is a common problem with w body cars and i was told this was cuz of its location in the engine compartment that exposed it to heat and the elements over time. whatever..i replaced it and that hasnt happened since and that was 3 years ago. Quote Link to comment Share on other sites More sharing options...
Jon89le Posted August 22, 2003 Author Report Share Posted August 22, 2003 Yup, it was the ECM. Cars running fine now. Now i just have a spare MAP sensor in my garage,lol. Quote Link to comment Share on other sites More sharing options...
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