Rough idle at start-up
 

First start-up of the day it has a rough idle for about 10 seconds, then levels out. During the rough idle I see some white smoke. Any ideas?

David

the cold is setting in...i see snow this morning.... test your glow plug's..first check the relay then each GP

Thanks Ron. I guess I'll have to run it in to the shop because I don't know how to check either. But, I appreciate you getting me headed in the right direction.

Thanks, David

Here is the latest.......

Dealership tested the GP's and the GP relay, all good.

Found number 8 injector bad, replaced and cleaned the other 7, also did a compression test, compression good..

Got it back, same problem, back to the dealership.

Dealer replaced ICP sensor. Next cold start, same problem.

Can anyone PLEASE help steer me in the right direction as to what this problem could be. I'm at my wits end! :-huh

David

Switch oil over to Rotella 5 -40 Synthetic. This will fix your problem if its when you first start the truck and its cold out and it does a kinda "bucking" idle jump for 5-10 seconds, then settles in normal.

It's a rough idle, very choppy, it lasts for about 10 - 12 seconds. After the first 2-3 seconds of the choppy idle I get white smoke from the tail pipe. Once the rough idle stops the white smoke stops. On a warm restart, no rough idle, no smoke, it only occurs after the truck sits and gets cold.

Does this sound the 5-40 Rotella synthetic will cure my problem? I'm a little curious what this could be caused from, I have used the Motorcraft 5-40 conventional oil since it was new and I have 196k on it now. Thanks, David

It will help, just for smoothness, but this sounds more like a Glow Plug Relay(GPR) Next cold start try jumpering the posts on the relay for about 30 seconds to a minute or so.

Thanks Big Al,

I put my test light on the load side of the GPR to see how long it is energized. I checked it twice and both time it stayed on for 35 seconds, so, when I cranked the truck the next time I paid no attention to the dash light and waited 35 seconds before I started the truck but got the same result. Rough idle and white smoke. This would indicate that the GPR is ok, correct? David

Not sure if this would help all that much but have you tried cycling your glow plugs a couple times before firing up the truck?

From my understanding, white smoke on ignition comes from unburnt fuel. There is a good chance your engine is surging cause of the cold, mine does that too some mornings.

My $.02, find a GOOD diesel mechanic in your town and stop going to the dealership. They'll @#$@#$*@&#$(*&# you all day long. I've never heard of a dealership that has the customer's best interest in mind. A local small shop with a good owner might be the other way around.

any engine codes? having a code puller is always to good investment, under $100 for something basic. AE costs a lot more and is worth the $$.

Thank you santacruz, good information and good advise. David

David,
You be amazed how the Rotella 5 -40 Synthetic smooths cold start ups and idle characteristics.
It definitely would not hurt to put that in next oil change.

As far as what else it could be, i would lean towards the GPR as others are saying too. WHen mine when bad it would pump out white smoke when trying to start then slowly go away as it got warm. Definitely would switch that out first since honestly that is the most common problem. Its very cheap and take 10 minutes to switch.

Thanks Silverbullet, I appreciate it. DAvid

Is it possible that 1 or more injector(s) are not closing and therefore dripping a little fuel so then I have excess fuel at start-up?

David

I had a GPR that would work intermittently and drove me nuts. It would light the test light but not at the full voltage that was needed to properly energize the glowplugs hot enough for the truck to start normally. I think you need to swap the GPR.