High Idle On Cold Start

[Wanderer]

I recently moved to northern bc (brrrrrr) AFAIK the truck spent most of it 315,000km in southern BC. During cold starts the idle steadily climbs to 3000rpm until warm then drops to normal. I know the idle should increase until warm but I thought 2000-2500rpm was normal. Would thinner oil solve this, currently using 10w30 with lucas oil addative, or is this normal?

 

Cheers,

Paul

[MY1PATH]

Fast Idle Screw-

Head points skyward and is often mistaken for the normal Idle Screw. When the engine is cold the 'fast Idle Cam' increases the idle for faster warm-up. This screw sets the fast idle speed which should be between 1,000-1,200 rpm set depending on how cold your climate is.

http://npora.ipbhost...53entry416253

There is also onother picture here with it on the vehcile. Hard to see but Its hard to see on the vehicle too. Hope this can be useful tool to you whenever you have a tbi question.

Edited November 27, 2009 by MY1PATH

[Wanderer]

Thanks mate, that's exactly what I needed!

[Wanderer]

So I backed the fast idle screw out half a turn and it seamed to drop the idle down about 200rpm. So I backed the screw out a full 3 turns and my cold idle is still over 3000rpm. Is it possible the fast idle cam is stuck (or gummed up) and needs to be freed up? Its currently -18C at noon and supposed to stay this cold all week (insert swear words here) so I guess my hands are gonna get cold.

[MY1PATH]

I would assume someting must be stuck or something else is making it behave that way. also, going back to your original post, you should use 5w30 for a climate that cold. Idono if it will help your idle but it should be done anyway.

[Alkorahil]

So I backed the fast idle screw out half a turn and it seamed to drop the idle down about 200rpm. So I backed the screw out a full 3 turns and my cold idle is still over 3000rpm. Is it possible the fast idle cam is stuck (or gummed up) and needs to be freed up? Its currently -18C at noon and supposed to stay this cold all week (insert swear words here) so I guess my hands are gonna get cold.

 

 

I had to replace mine back in the summer of 08.

Ended up it had rust on the inside and would not move completly back and forth. So did the EGR valve when I pulled it at the same time. Fixed my idle problem though.

It was doing 2500 rpm at start up in texas in the summer.

[Precise1]

So I backed the fast idle screw out half a turn and it seamed to drop the idle down about 200rpm. So I backed the screw out a full 3 turns and my cold idle is still over 3000rpm. Is it possible the fast idle cam is stuck (or gummed up) and needs to be freed up? Its currently -18C at noon and supposed to stay this cold all week (insert swear words here) so I guess my hands are gonna get cold.

 

That's just wrong!!

 

B

[Wanderer]

Thanks for the quick responses, I didn't think this forum was that active.

Anyways, I have another question, did our trucks come with block heaters? Being -20c outside (mid day) my truck won't start. Man will I be glad when I'm back on a southern gulf island!

[Alkorahil]

Block heaters were an add on accessory.

There were two different versions, one for 2WD and one for 4WD vehicles.

Both have been discontinued for some time but I might be able to still get them.

PM me if you are interested and I can see what it would cost. Let me know if your vehicle is 4wd or 2wd.

[Wanderer]

So it warmed up to a balmy -10 today so I went out to try and start my truck. I put a space heater underneath pointed at the oil pan, heat gunned various engine components, drained some of the thick oil out and topped it up with warm, thinner oil and put a battery charger on it. After all that she sputtered to life, success.... or not. As it started to warm up the idle started "looping" or "searching" between 1500rpm and 2000rpm. I hoped this would go away once the engine reached operating temp. but it continued to "loop" only faster.

Tomorrow I will check the EGR and PCV systems and also look for vacuum leaks. Other than that what else could be the problem? What vacuum lines should I be checking?

[MikeV]

Vacuum lines in that cold should be a fricken treat! It's -1C here and snowing like a bitch; time to start the sled my friend! and it better be electric start!

Maybe hit the vacuum lines with WD-40 while it is running and if it quits acting up for a moment then you know it is a cracked vacuum line but I doubt that is the issue. Damn EGR rust issue as rob was saying could be the issue.

I'll sound like a broken record...

try running seafoam thru the vacuum lines and down the "carb"

[Wanderer]

So I checked it out quickly today, EGR valve is functioning properly as far as I can tell (I pushed up on the underside and it opened and closed freely, a little squaky maybe. With engine idling when I pushed up the idle slowed). Didn't find a vacuum leak either. However the rubber hose that goes to the air cleaner has very little suction (I believe that is an indication of a problem with the PCV system, not sure though because the damn haynes manual is so vague). To be honest I'm not even sure if I located the PCV valve (haynes manual once again not very helpful).

Will seafoam clean the PCV valve and related components?

The idle is steady for the first few minutes after start up but then all of a sudden starts "looping"?

 

Also while I had the air cleaner off I turned the fast idle screw a few time and something is definitely stuck. The screw just gets really loose and the idle doesn't change.