L98 Acting Up
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
I've already tried resetting the IAC, and the TPS but it didn't work for me. The TPS is @ .54 volts and idle is unknown, since the car dies instantly after starting. When it was running however, i had the idle adjusted to be 500 in park.
If i could post a video, would you guys be able to make a more accurate guess/assumption of what it is?
I think my problem is with the fuel delivery because it starts up like its brand new then it just dies.
If i could post a video, would you guys be able to make a more accurate guess/assumption of what it is?
I think my problem is with the fuel delivery because it starts up like its brand new then it just dies.
Last edited by Pwnage1337; Mar 29, 2009 at 10:49 PM.
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
So spray some starter fluid in the throttle body and kick it over. see if it runs for more then 1 second.
Are you sure you have the TPS set right. or wired right.
Once again. can you hold like 1/2 throttle, then hit the key. see if it will rev up and stay on?
Are you sure you have the TPS set right. or wired right.
Once again. can you hold like 1/2 throttle, then hit the key. see if it will rev up and stay on?
Le Mans Master
Joined: Oct 1999
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Likes: 34
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
The set screw has been adjusted, when the car was running. Do you think that it could be off so much as to make the car not run?
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
I am asking these stupid questions to get more of a feel of what might be happening.
I would try putting some starter fluid, or gas down it's throat, and see if it runs a little longer. dont flood it.
This will help you figure out if it is a fuel problem. if it runs spraying something into the throttle body. You have a fuel issue.
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
ok i'll try to get some starter fluid and spray it in the TB. How much should i spray in there?
UPDATE!! RUNS WITHOUT THE MAF SENSOR PLUGGED IN.
What could it be? ECM?
UPDATE!! RUNS WITHOUT THE MAF SENSOR PLUGGED IN.
What could it be? ECM?
Last edited by Pwnage1337; Mar 30, 2009 at 05:43 PM.
Race Director
Joined: Jun 2004
Posts: 13,961
Likes: 707
From: WI
I suggested trying it without the MAF to see if it would run and possibly signify a vacuum leak. In a previous post you mentioned an exhaust gasket that's bad? I'm thinking you may have an air leak. Could try blowing smoke in the TB. Is the EST connector plugged in, is it damaged?
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Instructor
Joined: Mar 2009
Posts: 126
Likes: 1
From: Newington CT
I am an ASE certfied tech. and I use that trick on most of the older GM cars 98% of the time it turns out the MAF sensor is no good.
I have to ask though does the fuel rail still have the correct psi. after the car dies?
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
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From: Custer, WI
the fuel pressure holds at 39 psi after the car dies.
that MAF sensor is only 4 months old with like 1500 miles on it..what a ****in joke
the EST is plugged in, and it is not damaged. How do you blow smoke in the TB lol? SMOKE MACHINE AND STROBE LIGHTS?
that MAF sensor is only 4 months old with like 1500 miles on it..what a ****in joke
the EST is plugged in, and it is not damaged. How do you blow smoke in the TB lol? SMOKE MACHINE AND STROBE LIGHTS?
Last edited by Pwnage1337; Mar 30, 2009 at 11:16 PM.
Instructor
Joined: Mar 2009
Posts: 126
Likes: 1
From: Newington CT
I'll have to sleep on my answer for a bit.
But I'm pretty sure your MAF sensor is no good at this point.
Plug everything else back in and disconnect your battery to clear any codes but leave the MAF disconnected and try again...what happens now?
As for the smoke machine...we use them at work to find vacuum leaks by plugging it into an engine vacuum source and just wait for smoke to appear to find the leak...engine not running of course.
Instructor
Joined: Mar 2009
Posts: 126
Likes: 1
From: Newington CT
After reading the original post.
I'm now inclined to say put the old IAC and/or TPS back in if you can, I think you broke it?
Since it ran with the old one.
Are you sure the new connector is wired correctly?
If not the circuit in the ECM for the IAC or TPS may be fried now.
I'm now inclined to say put the old IAC and/or TPS back in if you can, I think you broke it?
Since it ran with the old one.
Are you sure the new connector is wired correctly?
If not the circuit in the ECM for the IAC or TPS may be fried now.
Last edited by Crzyfrlss1; Mar 30, 2009 at 11:44 PM.
Instructor
Joined: Mar 2009
Posts: 126
Likes: 1
From: Newington CT
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
After reading the original post.
I'm now inclined to say put the old IAC and/or TPS back in if you can, I think you broke it?
Since it ran with the old one.
Are you sure the new connector is wired correctly?
If not the circuit in the for the IAC or TPS may be fried now.
I'm now inclined to say put the old IAC and/or TPS back in if you can, I think you broke it?
Since it ran with the old one.
Are you sure the new connector is wired correctly?
If not the circuit in the for the IAC or TPS may be fried now.
I know the connector is wired correctly because the colors for the cables matched up and i'm not colorblind lol.
Burning Brakes
Joined: Feb 2009
Posts: 785
Likes: 3
From: Richmond Virginia
I had to just now register to tell you that your problem has been likely found.
I am an ASE certfied tech. and I use that trick on most of the older GM cars 98% of the time it turns out the MAF sensor is no good.
I have to ask though does the fuel rail still have the correct psi. after the car dies?
I am an ASE certfied tech. and I use that trick on most of the older GM cars 98% of the time it turns out the MAF sensor is no good.
I have to ask though does the fuel rail still have the correct psi. after the car dies?
That is a Old "quick and dirty" trick for checking the MAF....it does not set a "code" if the signal is not accurate...the ECM has no way of knowing that a sensor is lieing (not accurate) so to speak... it simply uses info from the MAF and other sensors to adjust the amount of fuel richer or leaner according to what it "thinks" are all truthful sensors...if you had a short or open in the MAF circuit then you'd set a code...if your "new" MAF is a reman. from one of the discount auto parts stores it very well MAY be bad. You may try cleaning it with some MAF cleaner, but more then likely it's bad. I'll finish by saying this...a new MAF may completely fix your problem if you haven't broken anything else by...removing/checking electrical connectors--turning screws or replacing other parts---JMO
Instructor
Joined: Mar 2009
Posts: 126
Likes: 1
From: Newington CT
That is a Old "quick and dirty" trick for checking the MAF....it does not set a "code" if the signal is not accurate...the ECM has no way of knowing that a sensor is lieing (not accurate) so to speak... it simply uses info from the MAF and other sensors to adjust the amount of fuel richer or leaner according to what it "thinks" are all truthful sensors...if you had a short or open in the MAF circuit then you'd set a code...if your "new" MAF is a reman. from one of the discount auto parts stores it very well MAY be bad. You may try cleaning it with some MAF cleaner, but more then likely it's bad. I'll finish by saying this...a new MAF may completely fix your problem if you haven't broken anything else by...removing/checking electrical connectors--turning screws or replacing other parts---JMOBut every time I've tried that trick the car ran just good enough to get it into the bay without pushing it.
The other thing that gets me is, the car ran before he changed the other sensors.
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
Alright, since this MAF is under warranty, i'll just go get another one.
Too bad they have to order it, because they did last time.
Also, this is a microtech MAF without a "hot wire" thing in it, instead its like a sheet of plastic with a little circuit board inside of it. I was told that sometimes these are better because if your Burn-off module is broken, you can just get a Microtech one and not worry about it.
I'll try cleaning it before i do anything else though.
Too bad they have to order it, because they did last time.
Also, this is a microtech MAF without a "hot wire" thing in it, instead its like a sheet of plastic with a little circuit board inside of it. I was told that sometimes these are better because if your Burn-off module is broken, you can just get a Microtech one and not worry about it.
I'll try cleaning it before i do anything else though.
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
I would try getting the right style MAF for your car. Also how long did the car sit over the winter? what dose the gas look like? try pumping some out into a clear glass container then let it sit a while check for water. It also sounds like you bought a used TPS you never know with a used electrical part. Good Luck
Last edited by floridamale; Mar 31, 2009 at 08:18 AM.