Car Won't Idle

Have a flashing light? Gauges acting funny? Bad idle? Get your problems solved...
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john266
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Joined: Tue Feb 26, 2008 10:57 pm
Location: Stuarts Draft, Va

Car Won't Idle

Post by john266 »

Hey guys, before I start tearing into this thing I was wondering if anyone had any ideas. I have a '90 3.1L, and when I got home from work today the car started running a little rough at idle. I came back outside later, and now the car won't start at all unless I hold the gas pedal about 1/4-1/2 way. As soon as it starts, if I let off the gas, the car stalls right away. The fuel pump is functional, and the IAC Valve is brand new. Could this possibly be a MAP sensor? I am kind of at a loss, because I have never seen a 3.1L do this.
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3X00-Modified
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Re: Car Won't Idle

Post by 3X00-Modified »

Could be map sensor, could be low fuel pressure, could be the crank position sensor... There are a few items that could cause this and not throw a code.

Do you have access to a fuel pressure gauge and a ECM scanner?
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john266
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Posts: 67
Joined: Tue Feb 26, 2008 10:57 pm
Location: Stuarts Draft, Va

Re: Car Won't Idle

Post by john266 »

Unfortunately I don't have access to either. I forgot to mention that the crank sensor is new too. I guess I will start with a MAP sensor today, and see what that does. I wouldn't doubt it if it was fuel related, because I have had to replace the fuel sender twice in the past 6 months, but even when the sender went bad, the car didnt act like this....
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Mr. Beefy
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Re: Car Won't Idle

Post by Mr. Beefy »

I would doubt that it's the MAP sensor. When the one in my GTZ went the car was fine at idle, but as soon as I gave it gas the car would stall till I went WOT.

That being said, do you smell unburned fuel out of the tailpipe when you are trying to start it? Could be the CTS gone bad.

Being that the car's a 90 you dont need a code reader to get the codes(even if the light isnt on it could have stored something usefull). Bridge the two upper right ports(A and B) on the OBD port with a paperclip. Then turn the car to the 'on' position (DO NOT start the car). Then count the lights,(flash, pause, flash flash would be a code 12, etc) and report back what you find.
john266
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Posts: 67
Joined: Tue Feb 26, 2008 10:57 pm
Location: Stuarts Draft, Va

Re: Car Won't Idle

Post by john266 »

All fixed! I threw a new MAP sensor at the car a few minutes ago, and she runs like a top again! Hehe, thats the first time I was actually right about something. Thanks again for your help guys!
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