Throttle Response Slow
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
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From: sw Ohio
Throttle Response Slow
I took a drive in my '85 yesterday and I noticed something thats probably been there, but I didnt notice. When I get on the gas theres probably a 1/2 second delay between my foot and the engine. Whats up with that?
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
Fuel pressure is good, just had the MAF replaced by the mechanic and he checked out timing, fuel pressure, wiring all the way to the ECM. Nothing wrong there. Could it be something from the pedal to the throttle body?
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
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From: sw Ohio
Well the mechanic did mention that the cat was glowing red and that was the probable cause for my stalling, rough idle problems, but he replaced the MAF and it worked fine. I have looked and have not seen the cat glowing at all, plus its only about a year old. Its going to be taken out soon anyway when I install my headers and straight pipes.
I would think its all in my head but it doesnt happen in any other car i've driven.
I would think its all in my head but it doesnt happen in any other car i've driven.
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Safety Car
Joined: Jul 2004
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Well the mechanic did mention that the cat was glowing red and that was the probable cause for my stalling, rough idle problems, but he replaced the MAF and it worked fine. I have looked and have not seen the cat glowing at all, plus its only about a year old. Its going to be taken out soon anyway when I install my headers and straight pipes.
I would think its all in my head but it doesnt happen in any other car i've driven.
I would think its all in my head but it doesnt happen in any other car i've driven.
Melting Slicks
Joined: Aug 2003
Posts: 3,380
Likes: 388
From: Lakeville MI
Check the vacuum level
Check the timing
Its a MAF car so the MAF needs to see the increase in airflow as it is occuring before fuel is added, so there is some delay and processing time involved like 100 ms or so. The ecm is always slighty behind.
Running a little bit rich helps to compensate for transients. You may also be a bit on the lean side if the vacuum and timing check out.
What was the MAF replaced with? OEM or Aftermarket. The MAF calibration may not be perfect, and probably isn't or the MAF itself may be slow to respond.
Primarily I suspect low vacuum caused by late ignition timing.
The weight of the pedal should take up any slack in the throttle cable. Do you notice the pedal sticking at all?
Check the timing
Its a MAF car so the MAF needs to see the increase in airflow as it is occuring before fuel is added, so there is some delay and processing time involved like 100 ms or so. The ecm is always slighty behind.
Running a little bit rich helps to compensate for transients. You may also be a bit on the lean side if the vacuum and timing check out.
What was the MAF replaced with? OEM or Aftermarket. The MAF calibration may not be perfect, and probably isn't or the MAF itself may be slow to respond.
Primarily I suspect low vacuum caused by late ignition timing.
The weight of the pedal should take up any slack in the throttle cable. Do you notice the pedal sticking at all?
Last edited by tequilaboy; Sep 8, 2007 at 10:08 AM.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
The MAF is an OEM Bosch that I took out of another TPI, so yeah its not new but it works. I have never noticed the pedal sticking, but it sure has a lot of slack in it, like if i push it up instead of down you can wiggle it all over the place. 
