Quick advice needed on L98 idle
Thread Starter
Team Owner
Joined: May 1999
Posts: 22,830
Likes: 13
From: Columbus Ohio
CI 3-4, 8-9-10 Veteran
St. Jude Donor '06-'08-'10
Quick advice needed on L98 idle
Is there an adjustment?
Steves 84 is bringing his new (to him) 87 vert by the house. He's having problems with it stalling at idle.
Any hints?
Thanks
Steves 84 is bringing his new (to him) 87 vert by the house. He's having problems with it stalling at idle.
Any hints?
Thanks
Burning Brakes
Joined: Apr 2002
Posts: 755
Likes: 0
From: Patterson CA
Re: Quick advice needed on L98 idle (Blue 92)
There is a minimum idle speed adjustment on the drivers side of the TB. But you should check the TPS voltage first (should be .54v +/- .08). Then check the IAC and TB to be sure they are clean.
Here is the set procedure for the min. idle speed, if you don't have a scan tool you will have to estimate on where you are setting it but you should be able to get close, and where it says to enter "field service mode" that is the same as jumping A+B on the ALDL :thumbs: This procedure is for and '89 but I do believe it is the same on an '87.
{Quote}
Idle Speed
A base idle adjustment is not normally required and should not be performed unless the base idle stop screw had inadvertently been misadjusted during servicing. On replacement throttle bodies, the idle stop screw is not adjusted and is not covered with a plug.
NOTE: If the minimum idle speed is adjusted too high, the IAC pintle will constantly seat in the throttle body, and may cause damage to the IAC valve. If the minimum idle speed is adjusted too low, the vehicle may not start in cold weather, or may stall during warm-up.
ADJUSTMENT:
1. Block the drive wheels and apply the parking brake.
2. Connect a scan tool to the ALDL connector.
3. Turn the ignition "ON."
4. Select TPS on the scan tool and adjust the TPS voltage.
5. Select "Field Service Mode" to seat the IAC pintle. After 45 seconds, disconnect the IAC connector and exit the "Field Service Mode."
6. Disconnect the distributor set timing connector.
7. Place the transmission in Park (A/T) or Neutral (M/T). Start the engine and run until operating temperature and closed loop conditions have been met.
8. Select "Engine RPM" on the scan tool.
9. Adjust idle speed if not within specifications.
10. Turn the ignition "OFF."
11. Connect IAC and set timing connectors.
12. Turn ignition "ON" and recheck TPS voltage.
13. Reset the IAC pintle position by doing the following:
• Depress the accelerator pedal slightly, start and run the engine for five seconds.
• Turn the ignition "OFF" for ten seconds, then start the engine and check for proper idle operation.
14. Disconnect the scan tool.
{/Quote}
[Modified by VetBoy89, 3:40 PM 3/3/2003]
Here is the set procedure for the min. idle speed, if you don't have a scan tool you will have to estimate on where you are setting it but you should be able to get close, and where it says to enter "field service mode" that is the same as jumping A+B on the ALDL :thumbs: This procedure is for and '89 but I do believe it is the same on an '87.
{Quote}
Idle Speed
A base idle adjustment is not normally required and should not be performed unless the base idle stop screw had inadvertently been misadjusted during servicing. On replacement throttle bodies, the idle stop screw is not adjusted and is not covered with a plug.
NOTE: If the minimum idle speed is adjusted too high, the IAC pintle will constantly seat in the throttle body, and may cause damage to the IAC valve. If the minimum idle speed is adjusted too low, the vehicle may not start in cold weather, or may stall during warm-up.
ADJUSTMENT:
1. Block the drive wheels and apply the parking brake.
2. Connect a scan tool to the ALDL connector.
3. Turn the ignition "ON."
4. Select TPS on the scan tool and adjust the TPS voltage.
5. Select "Field Service Mode" to seat the IAC pintle. After 45 seconds, disconnect the IAC connector and exit the "Field Service Mode."
6. Disconnect the distributor set timing connector.
7. Place the transmission in Park (A/T) or Neutral (M/T). Start the engine and run until operating temperature and closed loop conditions have been met.
8. Select "Engine RPM" on the scan tool.
9. Adjust idle speed if not within specifications.
10. Turn the ignition "OFF."
11. Connect IAC and set timing connectors.
12. Turn ignition "ON" and recheck TPS voltage.
13. Reset the IAC pintle position by doing the following:
• Depress the accelerator pedal slightly, start and run the engine for five seconds.
• Turn the ignition "OFF" for ten seconds, then start the engine and check for proper idle operation.
14. Disconnect the scan tool.
{/Quote}
[Modified by VetBoy89, 3:40 PM 3/3/2003]
Le Mans Master
Joined: Dec 1999
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From: And on the fifth day, subpoenas were served to Obama senior staff
Race Director
Joined: Feb 2002
Posts: 16,105
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From: Canal Winchester OH
CI 3-4-5-6-7-8-9-10-11 Vet
CI X Blind Auto-X Champ
Re: Quick advice needed on L98 idle (PeteL)
This problem seems to have just popped up today. Idle was fine when I started it up this morning. When I tried to start it at work, it would just turn over, like it wasn't firing or getting fuel. If I pressed the accelerator, it would run fine until I let off the accelerator and then stall. It then sit for about 45 minutes, I came out at lunch and it started fine no problems. Tonight leaving work, no problems. At the DMV ( of course ) it did the same thing, would run if I had the gas pedal pressed, but as soon as I let off, it would stall. On the way over here, it would idle at around 400 RPM, acting like it would want to stall. It did stall a couple of times. Now that I got to Blue92's house, It seems to be running fine again... :confused: :confused:
