98 lesabre throttle problems 3.8 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Buick When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made.

Reply
 
 
 
Thread Tools Search this Thread
Old 05-05-2014, 05:58 PM   #1
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Mar 2013
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Mweight is on a distinguished road
Default 98 lesabre throttle problems 3.8

So my car won't start when it'* hot. I'm getting a trouble code for the throttle position sensor. So I changed, still having the same problem and code. The car shifts fine when driving, but won't down shift even with the pedal to the floor. I've checked the wiring and can't see anything. Checked my ECM, because it acts like it'* not getting any spark when it warms up. That was good. Please help!!
Mweight is offline   Reply With Quote
Old 05-05-2014, 10:04 PM   #2
Senior Member

Certified GM nut
 
Tech II's Avatar
 
Join Date: Feb 2014
Location: Worcester, Ma.
Posts: 2,149
Thanked 783 Times in 612 Posts
Tech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond repute
Default

So my car won't start when it'* hot.

Pull your vac line off the fuel pressure regulator, and check for the presence of fuel....try starting with the MAF disconnected.......Do you have spark? Do you have good fuel pressure? Injector pulse?

I'm getting a trouble code for the throttle position sensor. So I changed, still having the same problem and code.

Did you check the signal voltage out of the TPS?....three wires, grey(5V), black(ground), and dkBlue is the signal voltage.....in the closed position, backprobe the dkblue wire, should be about 0.46V.....as you open the throttle it should increase linearly to about 4.7V.....if it doesn't, back probe the other wires checking for ground and 5V.....if ok, make sure the TPS is installed correctly and the linkage lever on the throttle plate is moving the lever on the sensor......

The car shifts fine when driving, but won't down shift even with the pedal to the floor. I've checked the wiring and can't see anything.

May not be getting a TPS signal to the PCM.....could be an open between TPS sensor and PCM.....

Checked my ECM, because it acts like it'* not getting any spark when it warms up.

How did you check your PCM?
Tech II is offline   Reply With Quote
The Following 2 Users Say Thank You to Tech II For This Useful Post:
damadtech (05-17-2014), WilliamE (05-06-2014)
Old 05-16-2014, 05:19 PM   #3
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Mar 2013
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Mweight is on a distinguished road
Default

Quote:
Originally Posted by Tech II View Post
So my car won't start when it'* hot.

Pull your vac line off the fuel pressure regulator, and check for the presence of fuel....try starting with the MAF disconnected.......Do you have spark? Do you have good fuel pressure? Injector pulse?

I'm getting a trouble code for the throttle position sensor. So I changed, still having the same problem and code.

Did you check the signal voltage out of the TPS?....three wires, grey(5V), black(ground), and dkBlue is the signal voltage.....in the closed position, backprobe the dkblue wire, should be about 0.46V.....as you open the throttle it should increase linearly to about 4.7V.....if it doesn't, back probe the other wires checking for ground and 5V.....if ok, make sure the TPS is installed correctly and the linkage lever on the throttle plate is moving the lever on the sensor......

The car shifts fine when driving, but won't down shift even with the pedal to the floor. I've checked the wiring and can't see anything.

May not be getting a TPS signal to the PCM.....could be an open between TPS sensor and PCM.....

Checked my ECM, because it acts like it'* not getting any spark when it warms up.

How did you check your PCM?
I changed the fuel pump a little mor than a month ago. New fuel filter. Injectors cleaned.
I took my ignition control module down to get tested. It passed. Waiting for my friend with a tester to come over
Mweight is offline   Reply With Quote
Old 05-16-2014, 05:20 PM   #4
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Mar 2013
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Mweight is on a distinguished road
Default

Quote:
Originally Posted by Mweight View Post
I changed the fuel pump a little mor than a month ago. New fuel filter. Injectors cleaned.
I took my ignition control module down to get tested. It passed. Waiting for my friend with a tester to come over
And a new MAF about 2 months ago
Mweight is offline   Reply With Quote
Old 05-16-2014, 08:32 PM   #5
Senior Member

True Car Nut
 
WilliamE's Avatar
 
Join Date: Jun 2011
Location: VA
Posts: 3,087
Thanked 418 Times in 376 Posts
WilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond reputeWilliamE has a reputation beyond repute
Default

Quote:
Originally Posted by Mweight View Post
I changed the fuel pump a little mor than a month ago. New fuel filter. Injectors cleaned.
I took my ignition control module down to get tested. It passed. Waiting for my friend with a tester to come over
A lot of the times an ICM will pass the that test, because when you take it in it has time to cool off, and it does not get heated up from all the heatsoak caused by engine operating temps, so just because it passed does not mean it is not faulting when the car heats up, considering all you have done, I cannot see much else that it could be, it is fairly common for the ICM'* to have issues with heatsoak if they are pretty old, at least from what I have heard, mine still works fine at 137k.

The next time you have the issue, I'd read this thread I am posting a link to, and test that ICM while it is hot, just be careful not to touch anything on the motor, I would not want you to get burned.

Part 1 -GM 3.8L Ignition Module Test and Crank Sensor Test (3X, 18X)
WilliamE is offline   Reply With Quote
The Following User Says Thank You to WilliamE For This Useful Post:
damadtech (05-17-2014)
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1995 LeSabre part throttle hesitation problem L27 68Electra 1992-1999 2 08-28-2010 10:36 AM
98 LeSabre; remove throttle body; drain coolant first? agrazela 1992-1999 4 01-25-2007 11:58 AM
Problems, Problems, Problems... swartlkk 2000-2005 2 11-04-2005 08:57 PM
Throttle Body and Throttle body spacer! DeeGee96SE Performance, Brainstorming & Tuning 5 06-29-2004 01:21 AM
problems, problems, problems big_boss2010 1992-1999 15 04-25-2004 09:05 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:43 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.