smoking at idle

AndySRT · **Posted:** Mon Sep 18, 2006 7:14 am

well i happend to notice yesterday that my truck is smoking like its running rich at idle. anyone have anyclue as to why my truck would be running rich at idle?

TDI4BY · **Joined:** Sun Apr 02, 2006 11:56 pm **Posts:** 644

What color is the smoke?

oldnavy · **Posted:** Mon Sep 18, 2006 9:15 am

If the smoke is black try a couple of WOT runs to see if it quites. If it does you are:

1. spending too much time at idle,

2. or putt, putting around,

3. or you are buying some really crappy fuel.

I suppect the cause is most likey some of all three. My wife is guilty of 1. and 2. senerios and I have to about every fill up take it and red line it once or twice to get rid of 20 lbs of soot built up in the exhaust system.

AndySRT · **Posted:** Mon Sep 18, 2006 10:35 am

it was defintly black smoke but i get on the throttle at almost any chance i get so its not #2. i do idle alot sitting on my job site so that maybe part of the problem. I try and pay attention to where i fill up but its not always the same place or do i see alot of trucks going there.

oldnavy · **Posted:** Mon Sep 18, 2006 10:45 am

AndySRT wrote:

it was defintly black smoke but i get on the throttle at almost any chance i get so its not #2. i do idle alot sitting on my job site so that maybe part of the problem. I try and pay attention to where i fill up but its not always the same place or do i see alot of trucks going there.

Once every station has the ULSD (46 cetane) that smoking problem should be reduced quite a bit for you, but the excessive idling will always contribute to the soot build up and smoking. What is causing that is the engine cylinders cools down and the fuel does not burn properly and you will even have some fuel that will make it past the rings into the oil. With this driving style you may want to do a 6500 mile oil change, I would have an oil sample tested at that point (oil change point) to see how the oil is holding up and if you are getting excess fuel into the oil. If no excessive fuel in oil then you can take oil change out to 10,000 or 12,500 miles and save a lot of money and worry.

AndySRT · **Posted:** Mon Sep 18, 2006 12:21 pm

i usually change the oil about 6500-7000 anyways because I am in dust practiaclly all day. thanks for the advice I'll send out a oil sample next oil change.

RFCRD · **Posted:** Mon Sep 18, 2006 9:49 pm

AndySRT wrote:

i usually change the oil about 6500-7000 anyways because I am in dust practiaclly all day. thanks for the advice I'll send out a oil sample next oil change.

The part that bugs me the most is the black smoking at an idle, usually not a good sign. No different than a gas motor smoking black, too much fuel and not enough oxygen. Start looking for the obvious stuff. Air filter? (since you are around a lot of dust), Air flow control valve sticking partially closed?, Low boost pressure/leak? Injector stuck? Are you injesting motor oil from the CAC? All can play a factor.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

If none of the things RFCRD mentioned check, try checking your glow plug resistance with the motor off. The connector block is on the engine block, on the drivers side, midway of the engine. When the connector is separated, the pins leading to all 4 glow plugs is easily reachable with an ohmeter. If they measure outside of .5 to 1.5 ohms, they may be bad. If they are, you should have a CEL or a code set soon.

When 2 of my gp's went bad after overuse by a failed egr valve last summer, they replaced the egr valve first and I had to drive it a week before they could get the gp's. It smoked so bad at idle it was embarrasing, especially at stoplights. And this was in August. 6 foot clouds of heavy black smoke on takeoff. As soon as they replaced them, it went back to clean burning.

RFCRD · **Posted:** Mon Sep 18, 2006 10:13 pm

Ranger1 wrote:

If none of the things RFCRD mentioned check, try checking your glow plug resistance with the motor off. The connector block is on the engine block, on the drivers side, midway of the engine. When the connector is separated, the pins leading to all 4 glow plugs is easily reachable with an ohmeter. If they measure outside of .5 to 1.5 ohms, they may be bad. If they are, you should have a CEL or a code set soon.

When 2 of my gp's went bad after overuse by a failed egr valve last summer, they replaced the egr valve first and I had to drive it a week before they could get the gp's. It smoked so bad at idle it was embarrasing, especially at stoplights. And this was in August. 6 foot clouds of heavy black smoke on takeoff. As soon as they replaced them, it went back to clean burning.

What really sticks in my mind is early signs of the EGR/Airflow CV/glowplug death spiral.

It's the easy fix to just jump 12v to each glow plug then take it to the dealer for warranty work? Three weeks later, will be as good as new!

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

What really sticks in my mind is early signs of the EGR/Airflow CV/glowplug death spiral.

Exactly. Again, entirely preventable, at least the gp death spiral. They have the PCM monitoring the burn temperature, the intake air temperature, boost pressure and it's the PCM activating the gp's. The max burn duty cycle of the gp is known.... so why no fail-safe with a code that says - cylinder temp too low, gp request burn cycle too long, then reduce the gp duty cycle and set a CEL + code? Sure would be less expensive than replacing gp's under warranty.

bugnout · **Posted:** Fri Sep 22, 2006 10:50 am

Andy,

You have the EHM installed right, thats probably were the smoke is coming. Mine does that until its warmed up.

smoking at idle

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