1996 7.3 white smoke cold and hot

Buddy_M · April 19, 2009

OK Guys, I'm kind of at a loss at this one. I have a customer that came in with a 96 7.3 with 82k miles that white smokes all the time. Checked the basics on it, has 2 glow plugs out and relay is good and new. This truck even has a decent white smoke that will bring your eyes to a nice water after just a few seconds of running in the shop, and it does not matter if the engine is hot or cold, it does this all the time. Ran KOEO, KOER, CCT, & Buzz test and all pass no codes. Crankcase pressure is ok, I don’t have the proper adapters for it, but there is not much blowby coming out with the filler tube open and the CCV hose plugged. Also checked fuel filter housing for oil thinking an injector o-ring issue and it is clean, and the coolant and oil is ok, and he says he never has to add either fluid between oil changes.

Now another catch to this truck had been rolled over on its passenger side about 20k ago, and hydrolocked when they tipped it back over and tried to start it. They found a bent pushrod and replaced one injector after it hydrolocked from what the owner told me. I am leaning towards thinking either a base engine problem, or internal injector problem or bad spray pattern yet, but the lack of blowby with the crankcase pressure and no codes with the CCT make it hard for me to tell him he may need injectors or there’s a further issue with the base engine. Just wondering if anyone has any advice on if they have either dealt with something like this before, or how much I should really tear into this to find out the problem. It does run OK plenty of power and no other issues, so I’m sure if it will cost too much they will just live with it.

Buddy

LARRY BRUDZYNSKI · April 20, 2009

Do you have a good Injection shop that can run them on a test stand? If not you could send them to me and i'll have them tested, runs about 80 bucks to test but it's worth it.

Keith Browning · April 20, 2009

Well if you are going to consider pulling the injectors it would be in your best interest to perform a compression test while the covers are off before doing anything. That will establish the condition of the engine.

scott1984 · April 20, 2009

i say remove valve covers both sides and start it up and unplug each injector to see if a change is made if not pull all 8 injectors out and inspect them as well as the cups

Aaron · April 20, 2009

Or just use the injector interrupt box.

What does the smoke smell like? Oil? Fuel? Coolant?

Buddy_M · April 20, 2009

Aaron, the smoke does have a fuel smell to it.

Keith, a compression test is in order for this truck to get a better idea when it comes in Thursday, and I will also unplug the injectors to try and individually cancell out injectors since I dont have an injector interupt box.

Larry, it was suggested to the customer possibly removing the injectors and send them off to be tested. That will depend on if he can leave the truck down for a week with shipping of the injectors.

Buddy

dieseldoc · April 22, 2009

It is possible you have a split injector tip or leaking nozzle. You could watch the mass fuel to see if it is in spec. On a CAT a split tip will make them smoke really bad and generally roun rough. However I have had a couple that ran awesome just smoked white all the time. Removed the exhaust manifold and found a wet exhaust port. Cleaned it out and started with the manifold off, that hole became wet with fuel again. Replaced that injector, smoke cleared right up. Obviously it is not real easy to remove the manifolds, but could be an option. If it hydrolocked possibly a bent rod, I had that be the cause of white smoke, that engine did have the sound of a slight miss though.

LARRY BRUDZYNSKI · April 22, 2009

Re-read the post...

Quote:

relay is good and new.

Who has done what to the truck before you??? It sounds like somebody has had their hands on it first. I would find out whats been done and re-evaluate it...

scott1984 · April 22, 2009

injector interrupt box will eat up a idm if not very careful

Buddy_M · April 22, 2009

The thought of possibly pulling manifolds to watch for smoke out a particular cylinder has crossed my mind if it comes down to it. I have done that before on an 855 Cummins with a similar issue.

Larry, the relay was replaced by me just a couple months ago, and it is still within limits of the voltage drop test. The truck sat in a body shop and the shop of a used car dealer for about a year while the body was worked on and the bent pushrod was replaced in that same time. I know the mechanic at the used car dealer, and he had also replaced one injector in it thinking that was causing the miss until he found the pushrod.

Yes, I do plan on starting with some basics once it comes in. I only had a few minutes to look at it on Saturday to just run a few tests with the scan tool, not much time to actually pull valve covers or anything else at the time.

Buddy

Buddy_M · April 24, 2009

Got the truck in late last nite, enough time to pull the valve covers and then did a compression test on the passenger side this AM. 300psi average on just the passenger bank. Knowing the customer as a friend also, I'll probably put a set of glow plugs in since theres a few bad ones and he'll live with the constant white smoke. Surprisingly, he has never complained of a hard start cold though, even with the bad GP's this winter.

Buddy

Bruce Amacker · April 24, 2009

What's your altitude? 300 is quite low, you know, right? What's MFDES at a hot idle? It should be between 8-12mg on a good engine, higher indicates fuel starvation from low FP or bad injectors. I'd suggest filling the FF with Stanadyne and seeing if it changes the way it runs/smokes. Low quality low cetane fuel will do this, too. Even with low compression, a set of injectors is likely to help.

Good Luck!

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Buddy_M · April 27, 2009

Our altitude here is about 18-1900ft, and yes I realize 300psi is quite low. I am thinking I may have a gauge issue, as there is little blowby, and it reads the same across all 8, and there is no starting or performance problems other than the smoke. This was a new gauge set as well, so I have not used it before to know if it is good, and have nothing to compare it to for proper readings.

I did find out also that is was not a bent pushrod replaced, but the connecting rod was bent & injector on #4 cylinder.

Bruce, MFDES is 12 at hot idle, and FP is good under load(50psi). This time running KOER I also got a P0236, which i have not looked into yet.

Buddy