happening again

drgnracin72 · 08-14-2007, 11:14 AM

truck is still shooting a lot of black and white smoke when going at a constant speed for around 25 mph, it doesnt do it at lower speeds but at 75 and 80, if you have the cruis on, it will start smoking badly and lose a lot of power after about 25-30 mins of constant speed. it also develops a serious knock in the engine while this is going on,

if i get out of it and slow down to 65 it goes away and then its good again for awhile, but im scared to drive my truck. its happened to the last 3 tanks ive put in the truck and no way have ai gotten 3 bad tanks of diesel from 3 differetn shell stores. im running the propper low sulpher diesel. anyone have any ideas.

it was in the dealsership for this last month and they changed fuel filter, and ran some conditioner through the tank.

lemme know what yall think,. its going back to the dealership again tommorow.

**ob_1jr** · 08-14-2007, 03:52 PM

What year truck is this on? I am betting injectors, but more info is needed.

SANCGCS · 08-15-2007, 07:13 AM

Definetly sounds like injectors to me. The dealer should be able to tell you what the injector balance test turned up and what your flow rate is. These will be able to tell you in what condition your injector are in. How did the fuel treatment work that the dealer put in. Did that help in clearing it up? I currently use the lucas injector care but also try the stanadyne performance additive. Check your engine oil level.

drgnracin72 · 08-16-2007, 12:49 PM

its an early 2007 classic body style. anyays i couldnt duplicate it after it got out of the dealership, but i never did what was triggering it. at that time, i didnt knwo exactly what was casuing it, but after its happened multiple times ive found its only after doing 75-80 for an extended period of time.

ill ask what the injector tests showed next time iom there and post the results and see wha yall have to say

**TYREBOYZ_DEMAXIN** · 08-16-2007, 02:40 PM

is it posible to have a bad engine tune from factory,if so what would happen if they would reflash the ECM?

lmantwell · 08-18-2007, 08:02 AM

How long do you think a 2500 Duramax Diesel could go on an injector that is misfiring?

**ob_1jr** · 08-18-2007, 11:11 AM

Not a real long time. I would get it fixed as soon as possible or you risk damage to the engine. In most cases when the injectors go bad they leak fuel in the crankcase and it thins out your oil. I don't know if you can tell if it is misfiring though.....I guess that is basically the balance checks that you do. They also test the return rates of the injectors too.

drgnracin72 · 08-18-2007, 01:11 PM

well if it screws up the motor, its covered by warrenty, but still, its kinda scary. not much i can do about it untill i get back from this job