Runs rough when first started up
Amateur
Joined: Jul 2006
Posts: 47
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From:
RE: Runs rough when first started up
ORIGINAL: steve05ram360
do this Reid.... next time it's convinient pop the hood and take a blow dryer to the IAC valve. heat it up some, then fire it up and take it for a short drive. see if you still have the problem. I bet your IAC is sticking. if so, you can try to yank it and spray some lube on the shaft area, it may just have some gunk in there that may need to be coaxed from its current spot. or if it does point to the IAC, you may just want to replace it.
do this Reid.... next time it's convinient pop the hood and take a blow dryer to the IAC valve. heat it up some, then fire it up and take it for a short drive. see if you still have the problem. I bet your IAC is sticking. if so, you can try to yank it and spray some lube on the shaft area, it may just have some gunk in there that may need to be coaxed from its current spot. or if it does point to the IAC, you may just want to replace it.
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: Runs rough when first started up
If one of the eight fuel injectors is leaking
or 'dribbling' fuel after it has been shut off
it could cause the rough running after a cold start.
When the engine is shut down
the leaky fuel injector(s) will slowly allow the gasoline
remaining in the fuel rail to drip into the intake manifold.
When started back up hours later
the cold gasoline will not all evaporate quickly
and the cold engine will idle ok on an even richer than normal mixture
[idle is very rich anyway]
But when you try to apply enough throttle to get considerable horsepower
to accelerate and drive, the out of whack mixture will cause sparkplugs to
'wet out' and missfire until the excess gasoline gets cleared out from the
intake manifold after a few minutes of higher airflow.
or 'dribbling' fuel after it has been shut off
it could cause the rough running after a cold start.
When the engine is shut down
the leaky fuel injector(s) will slowly allow the gasoline
remaining in the fuel rail to drip into the intake manifold.
When started back up hours later
the cold gasoline will not all evaporate quickly
and the cold engine will idle ok on an even richer than normal mixture
[idle is very rich anyway]
But when you try to apply enough throttle to get considerable horsepower
to accelerate and drive, the out of whack mixture will cause sparkplugs to
'wet out' and missfire until the excess gasoline gets cleared out from the
intake manifold after a few minutes of higher airflow.
Legend
Joined: May 2005
Posts: 8,661
Likes: 7
From: Central Oklahoma
RE: Runs rough when first started up
Can a fuel injector leak? I've been told that injectors either leak or they don't. Please elaborate. I need to add this information to my (continuing) wealth of knowledge.
Thread Starter
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Grand Champion
Joined: Nov 2004
Posts: 6,099
Likes: 6
From: Colorado
RE: Runs rough when first started up
ORIGINAL: HankL
If one of the eight fuel injectors is leaking
or 'dribbling' fuel after it has been shut off
it could cause the rough running after a cold start.
When the engine is shut down
the leaky fuel injector(s) will slowly allow the gasoline
remaining in the fuel rail to drip into the intake manifold.
When started back up hours later
the cold gasoline will not all evaporate quickly
and the cold engine will idle ok on an even richer than normal mixture
[idle is very rich anyway]
But when you try to apply enough throttle to get considerable horsepower
to accelerate and drive, the out of whack mixture will cause sparkplugs to
'wet out' and missfire until the excess gasoline gets cleared out from the
intake manifold after a few minutes of higher airflow.
If one of the eight fuel injectors is leaking
or 'dribbling' fuel after it has been shut off
it could cause the rough running after a cold start.
When the engine is shut down
the leaky fuel injector(s) will slowly allow the gasoline
remaining in the fuel rail to drip into the intake manifold.
When started back up hours later
the cold gasoline will not all evaporate quickly
and the cold engine will idle ok on an even richer than normal mixture
[idle is very rich anyway]
But when you try to apply enough throttle to get considerable horsepower
to accelerate and drive, the out of whack mixture will cause sparkplugs to
'wet out' and missfire until the excess gasoline gets cleared out from the
intake manifold after a few minutes of higher airflow.
I didn't think idle mixture was rich at all. In fact, it should be very close to the ideal stoichiometric point (about 14.7:1). Unless coldstartup idle is richer then warmed up idle.
Hall Of Fame
Joined: Jan 2004
Posts: 12,943
Likes: 308
RE: Runs rough when first started up
ORIGINAL: HankL
If one of the eight fuel injectors is leaking
or 'dribbling' fuel after it has been shut off
it could cause the rough running after a cold start.
When the engine is shut down
the leaky fuel injector(s) will slowly allow the gasoline
remaining in the fuel rail to drip into the intake manifold.
When started back up hours later
the cold gasoline will not all evaporate quickly
and the cold engine will idle ok on an even richer than normal mixture
[idle is very rich anyway]
But when you try to apply enough throttle to get considerable horsepower
to accelerate and drive, the out of whack mixture will cause sparkplugs to
'wet out' and missfire until the excess gasoline gets cleared out from the
intake manifold after a few minutes of higher airflow.
If one of the eight fuel injectors is leaking
or 'dribbling' fuel after it has been shut off
it could cause the rough running after a cold start.
When the engine is shut down
the leaky fuel injector(s) will slowly allow the gasoline
remaining in the fuel rail to drip into the intake manifold.
When started back up hours later
the cold gasoline will not all evaporate quickly
and the cold engine will idle ok on an even richer than normal mixture
[idle is very rich anyway]
But when you try to apply enough throttle to get considerable horsepower
to accelerate and drive, the out of whack mixture will cause sparkplugs to
'wet out' and missfire until the excess gasoline gets cleared out from the
intake manifold after a few minutes of higher airflow.
naw, actually on 2nd thought that wouldnt be the case. if you had 1 cylinder with a problem you could tell it was 1 cylinder. your problem is more related to all cylinders from what I can tell. I still say IACV...
Thread Starter
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Grand Champion
Joined: Nov 2004
Posts: 6,099
Likes: 6
From: Colorado
RE: Runs rough when first started up
More information to add:
This morning, I had to scrap the windows due to snow and ice. From standing outside, I reached in and turned the key. It fired right up and idled just fine. Clearing the snow and ice took about 5-10 minutes I waould say. When I got it and took off, it was perfect. So even warming up at idle can seem to cure it. I just hate sitting there most mornings when it is not snowy and icy to let it warm up for 5-10 minutes before driving off.
Here is a thought I have been tumbling around my cranium. I noticed that the Autolite 3923 plugs have a differnet type of gasket ring at the bottom of the threads. This gasket is what is supposed to act as a seat and seal the plug when you tighten it down. What happens if that seal around a plug is not good (either from undertightening or overtightening)? I would think you would lose compression as the combustion is allowed to blow by the plug, or at least leak a little, that could cause rough idle until the expansion of the metal due to heat creates a good seal around the plug (which would probably happen pretty quickly as heat expansion occurs). Just a theory I have, and it is addressed a little on the NGK website:
http://www.ngkspark.com.au/tech_inde...g_analysis.htm
This morning, I had to scrap the windows due to snow and ice. From standing outside, I reached in and turned the key. It fired right up and idled just fine. Clearing the snow and ice took about 5-10 minutes I waould say. When I got it and took off, it was perfect. So even warming up at idle can seem to cure it. I just hate sitting there most mornings when it is not snowy and icy to let it warm up for 5-10 minutes before driving off.
Here is a thought I have been tumbling around my cranium. I noticed that the Autolite 3923 plugs have a differnet type of gasket ring at the bottom of the threads. This gasket is what is supposed to act as a seat and seal the plug when you tighten it down. What happens if that seal around a plug is not good (either from undertightening or overtightening)? I would think you would lose compression as the combustion is allowed to blow by the plug, or at least leak a little, that could cause rough idle until the expansion of the metal due to heat creates a good seal around the plug (which would probably happen pretty quickly as heat expansion occurs). Just a theory I have, and it is addressed a little on the NGK website:
http://www.ngkspark.com.au/tech_inde...g_analysis.htm
Joined: Oct 2006
Posts: 38
Likes: 0
From:
RE: Runs rough when first started up
Same thing used to happen to my old S-10. And my 01 ram 1500. Both were manual transmission. I think it is just a bi-product of having a manual. Until things warm up a bit the ride can be ruff.
Captain
Joined: Oct 2006
Posts: 732
Likes: 0
From: Suffolk, VIRGINIA
RE: Runs rough when first started up
i have same problem.... but never seems to be an actual problem... it is as he said above, as if the engine is just warming itself up when cold.. in summer time here, it never did that. now that it is cold, it does it more often....
no problems here with rough idling at first, once warm, runs great
no problems here with rough idling at first, once warm, runs great
All Star
Joined: May 2006
Posts: 994
Likes: 0
From: Belle Plaine, Minnesota
RE: Runs rough when first started up
With the price of gas I drive an old beater to work - 89 Pontiac Grand Am that gets 33 MPG. Anyway, this car has the same exact issue as is being talked about in this thread. Starts right up, idles rough for a few minutes, then runs good after it is warmed up. If I try to drive it before it is warmed up it bucks and spits and gets downright ornery. It's worse the colder it gets. Already had to replace the O2 sensor due to a broken wire, but that did not help. I just let it warm up to make my morning less hectic. Does the same thing in the afternoon if the temps are low enough.
If you all find out something that works, or I fix the car we can post the info here and let everybody know what to do.
If you all find out something that works, or I fix the car we can post the info here and let everybody know what to do.
