LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

failed MAP sensor symptoms

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Old 09-01-2004, 10:38 PM
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Question failed MAP sensor symptoms

Well Ive checked plugs and wires, Ive replaced fuel filter, checked EGR Valve, its a new Opti, new WP, and all my wires seem to be in good shape (on the outside anyways ).
So..would a faulty MAP sensor cause a stumble during light/heavy acceleration? Its very consistant and a huge power loss. Car never dies though or stalls (M6). I do know that the 'green' clip that plugs into the MAP on mine, is broken...but its still plugged in just fine. The part that 'clips' onto the MAP sensor is broken off, dont even know how or when that happened. Could this cause any issues? and could a bad MAP cause a consistant stumble/loss of power? It happens all the time right at 2500RPMs and on up. But at idle or really slow acceleration, its fine. Thanks
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Old 09-01-2004, 10:56 PM
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Re: failed MAP sensor symptoms

Poor MAP performance can cause poor driveability and bad gas mileage. Best way to tell what the MAP sensor is doing is to monitor it with a scan tool.
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Old 09-02-2004, 12:30 PM
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Re: failed MAP sensor symptoms

Thanks for the info Shoebox..Ill see if I can get an auto parts store to run a test...with the tests they run, does anyone think they can detect it? Or would I need a full diagnostic tool for it (or maybe thats what they use?)
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Old 09-02-2004, 12:50 PM
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Re: failed MAP sensor symptoms

A parts store is probably only going to scan for codes. Maybe they will rent you a scan tool.
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Old 09-02-2004, 07:54 PM
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Re: failed MAP sensor symptoms

My stumble turned out to be a failed coolant temp sensor. The temp. reading would jump around making the pcm switch to open loop and back.
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Old 09-02-2004, 08:02 PM
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Re: failed MAP sensor symptoms

If your MAF is making the car run really rough, what you can do is unplug it and then take it for a ride and see if it smooths out. Alot of times the car will run better with the MAF unplugged (assuming its the MAF thats bad) Its the cheapest, quickest, easiest thing you can do.
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Old 09-02-2004, 08:13 PM
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Re: failed MAP sensor symptoms

Originally Posted by slayer6x6
If your MAF is making the car run really rough, what you can do is unplug it and then take it for a ride and see if it smooths out. Alot of times the car will run better with the MAF unplugged (assuming its the MAF thats bad) Its the cheapest, quickest, easiest thing you can do.
I believe he was asking about the MAP sensor.
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Old 09-03-2004, 09:49 AM
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Re: failed MAP sensor symptoms

Originally Posted by n2oCamaro
I believe he was asking about the MAP sensor.
oops
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Old 09-03-2004, 07:03 PM
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Re: failed MAP sensor symptoms

GM MAP sensors are bullit proof. You're probably wasting your time looking at that sensor. Unless it is physically damaged in some way. I did however notice 2 things in your signature. a K&N and a ported MAF. First, did you have the MAF or I should say the PCM calibrated for the porting. If not, that will kill your performance faster than a grandmother in an orgy. Most tuners will tell you not to mess with the MAF. The second issue is with the filter. It's easy to over oil the thing and that and dust sticks to the wiring in the MAF. If I were you, I would focus my attention there. Perhaps a working MAF from another car would be helpful.
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Old 09-04-2004, 10:07 PM
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Re: failed MAP sensor symptoms

Fix the connector. They dry out and crumble. It may appear that the sensor is "plugged" in, but the sensor output voltage can be be erratic. I just helped a guy in another thread, who had a MAP trouble code, and it ended up being the cracked connector. The sensors themselves are "bullet proof" (mine has also proven to be nitrous explosion proof ) but the harness connectors are a major problem. I have replaced my connector for the same reason.
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Old 09-05-2004, 01:23 PM
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Re: failed MAP sensor symptoms

i had the same trouble with mine last week. my sensor was loose from the clip breaking off somehow. check engine light came on so i had a diagnostic check done for free at my auto parts store. turns out without the clip the circuit isnt complete. obviously..... i just added a clamp to it and it runs great again. light doesnt turn on anymore and no acceleration problems anymore. hope this helps.
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Old 09-05-2004, 01:46 PM
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Re: failed MAP sensor symptoms

Originally Posted by jare23
i had the same trouble with mine last week. my sensor was loose from the clip breaking off somehow. check engine light came on so i had a diagnostic check done for free at my auto parts store. turns out without the clip the circuit isnt complete. obviously..... i just added a clamp to it and it runs great again. light doesnt turn on anymore and no acceleration problems anymore. hope this helps.
Any pictures or directions on how to fix the MAP connection plug? I'm not the most handy person with wires
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Old 09-05-2004, 03:26 PM
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Re: failed MAP sensor symptoms

Originally Posted by toby360
Any pictures or directions on how to fix the MAP connection plug? I'm not the most handy person with wires
I'm with him. My clip is broken and I would like to replace it as well.
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Old 09-05-2004, 03:39 PM
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Re: failed MAP sensor symptoms

You can replace it with a new pigtail. Comes with crimp connectors or you can strip, solder and heatshrink.

1993-1997 MAP sensor pigtail
AC-Delco #PT123
GM p/n 12085502

Also possible that you could find a new connector at your local auto supply.
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Old 09-05-2004, 06:32 PM
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Re: failed MAP sensor symptoms

Originally Posted by shoebox
You can replace it with a new pigtail. Comes with crimp connectors or you can strip, solder and heatshrink.

1993-1997 MAP sensor pigtail
AC-Delco #PT123
GM p/n 12085502

Also possible that you could find a new connector at your local auto supply.
yea better to ask this guy. i dont have a clue. i just used a tie wrap since my parts store said they dont carry anything like that. later on i figured i would just replace the whole sensor. but ill try this with shoebox.
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