prkiller

Hello all,

I recently added a commander with an XZT for towing. Hooked up my goose and headed east for a 5k round trip.
I had been running my truck on level 3 (65hp) for the best towing.
On the way back around the 4200 mile mark, after a fuel stop, got back on the highway and the truck started to sputter on WOT. If you had the truck on level 3, and you ran in 6th gear at highway speed at WOT, the truck would sound like it was "missing" like at least one of the cylinders was not firing and the exhaust was a LOT of smoke with a white-ish color right out of the exhaust going quickly to black as it went into the air.
For the rest of the trip (last 800 miles), if I had the commander on level 3, it would do this, level 2 was much less smoke and the miss was much less pronounced, but still noticeable. Level 1 was very hard to tell anything was wrong and level 0 (stock) was completely fine! Truck ran fine and had no issues.
So, for the remainder of the trip, I just kept the commander on stock and suffered through the climbs with the diminished power level.
I was pulling a trailer roughly 17k and the truck did great.

I'm looking for some educated guesses at what could be wrong.
Could it be something with the XZT overfueling the truck on the higher levels?
Could I have gotten a dirty load of fuel and now the truck doesn't like any of the fuel I put in? After the load in question, I put another 3 in on the way home, all from different stations along the way.

Problem is, I don't have a problem on stock, so it's not like the dealer is going to be able to do anything for me because the truck is totally fine in stock mode!

I should mention that the truck once in awhile on a cold morning when I first start it up stumbles twice, makes a loud clank clank, then idles fine!
Also, after the smoke started, when on level 3, it seems like the EGTs climb much faster than they used to.

I've only owned this truck about 7k miles and I'm totally new to diesels.

Thanks for any info anyone can provide!

shortbed rv

Did you get the fuel pressure kit? What was the fuel pressure and rail pressure when you had problems?

Your EGT will climb faster when pulling a heavy load at high altitudes.


BTW: with just the XZT I can pull my fuel pressure to zero in about 7 or 8 seconds at WOT. Since you were towing heavy it may not take you that long.

prkiller

Yes, I have the fuel pressure kit!

Always have the fuel pressure selected to show and it never goes below 3psi even climbing hills.

I've had the commander set to defuel at 1350 since day 1 and climbing the long grades going east at the start of the trip and keeping the throttle buried, letting the commander do it's job and defuel to level 2, I never saw below 3psi!

Speed Shift

Sounds like a failed injector

prkiller

I also pulled over after this on the way home to smell the oil and it had no diesel smell.
Is that the best way to check for a failed injector?
Thanks..

vzdude

Keep it simple. Try changing the fuel filter first, and double check the air filter. Could be a very simple fix. Also check for any codes.

prkiller

Will check filter and change fuel filter. Just changed the fuel filter before I left, but I'll change it again for good measure.

If I had a code, wouldn't I have a check engine light? Don't have the light...

chrleb1

You need more than 3 psi. That is too little to do the job. You need at least 10-15. The first pump in the cp3 needs a good supply get filled.

barryp

My truck does that with the XZT on or off. My fuel pressure goes to 1psi, I think that might be your same problem. The stock lift pumps dont work too well on some trucks.