12 Valve Engine and Drivetrain Talk about the 12V engine and drivetrain here. This is for 1994-1998.5 engine and drivetrain discussion only.

Motor dies quickly unless I hit pedal @ cold start

Old Mar 29, 2005 | 04:35 PM
  #1  
Palmetto_kid's Avatar
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From: Sweeny, Texas
Motor dies quickly unless I hit pedal @ cold start

This is how I start my truck:

I turn the key on, and while I am waiting for the wait to start light to come on, I press the accelertor down 1/2 way max. Once the light goes out, I turnt he key. When it fires, I release the pedal (this happes very quickly). It fires off almost instantly.

Here lately I have noticed that it will die after it fires off if I dont help it out some.(help it by pressing the pedal a little)

Other than that, the truck runs great. Im just wondering why it is dying. This never happened on my other 2 trucks.

EDIT: cold start is a 60* morning.
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Old Mar 29, 2005 | 05:03 PM
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From: London, ON
Raise the idle
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Old Mar 29, 2005 | 05:18 PM
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Smokee is probably correct. What your describing is the symptom of an idle speed that is too low.
May want to bump up your idle speed a bit and see if the problem goes away.

Rich.
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Old Mar 29, 2005 | 06:24 PM
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The usual reason the idle speed drops on a 12 valve is that the timing has backed down below 10 degrees. Bumping the idle is a band-aid, check your timing and get it back up to at least the specification found on the CPL. Your idle speed will pick right up where it belongs.

If it is the 24 valve, check your ODBII codes for an error from the IAT or MAP.
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Old Mar 30, 2005 | 04:50 AM
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Had same problem,even tho idle when warm was 725. Bumped it to 800+ and truck starts with no pedal and stays running when cold.
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Old Mar 30, 2005 | 08:38 AM
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I have had to bump my idle a few times. I keep it a little lower, i prefer it over the spec'd 780.
How do you go about checking the timing , etc.?
timing is somthing ive only done on a gasser in the past
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Old Mar 30, 2005 | 09:21 AM
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Originally posted by RCW
The usual reason the idle speed drops on a 12 valve is that the timing has backed down below 10 degrees. Bumping the idle is a band-aid, check your timing and get it back up to at least the specification found on the CPL. Your idle speed will pick right up where it belongs.
I strongly disagree. The reason the idle changes on a 12 valve is because the metal to metal contact of the screw tip and it's contact gets hammered from engine vibration. It's very obvious when you look at one close what has happened. It's a pretty fine adjustment, doesn't take much for the idle to drop.
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Old Mar 30, 2005 | 09:24 AM
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I will look into it.
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Old Mar 30, 2005 | 09:25 AM
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From: WA
The idle stop gets worn down and idle speed is reduced so you have to adjust the idle to compensate for wear, mine was so low when I bought the truck it wouldn't even start without giving it throttle, and had to keep my foot on the throttle for a couple minutes before it would idle on its own, no timing adjustment needed, just set the idle.
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Old Mar 30, 2005 | 08:25 PM
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From: TERRA CEIA FLORIDA
i agree with the idle as well. i adjust mine about every year or so...it will drop down then i turn it back up...performance never changes..just the idle speed
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Old Mar 30, 2005 | 09:10 PM
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From: Frankfort, Ky.
Phillip

It's Prob the idle screw.

If that's not the prob. you could have low fuel pressure.
that would prob. be a weak overflow valve.
Check fuel pressure.


Did you get the KDP and front seal fixed ?

: Eddie :
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Old Mar 31, 2005 | 07:02 AM
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I sure havent eddie. I have been too busy. I might try tonight. I have some things I have to fix on the PSD, and I might tackle the KDP afterwards.
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Old Mar 31, 2005 | 02:01 PM
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From: Austin, TX, Toronto, ON
its a simple idle adjustment...dont worry about it....i start mine in the cold up here and hold it to 1000 rpms for about 6 sec...in the summer i dont need to..no worries and my idle's at 800 or 850
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