Turbo issues please help!!!

[d2rvk]

Lately my turbo has been delaying a second or two when pulling away from a start when i look back i can see a poof of blackish smoke. also i have been finding soot on my air filter lately. any ideas???

Thanks Rick

[DA BIG ONE]

Pull the codes then we will have a better picture.

[DennisG01]

In addition to the the above recommendation, and in regards to soot on your filter - do you have an "open style" air filter? I mean, is it not inside a box? Can you give us a little more info?

[d2rvk]

Right now the ses light is not on but it has been on for mass air flow sensor. the air box does not seal up very well i have taped it up but the shop took off the tape when they turned off the ses light. my air filter is like a month old new it was pure white now it is all sooty. Last night i tried spraying wd40 in to the vacuum line on the waste gate vacuum hose.

thanks

[Robyn]

If the MAF is having issues it will mess up the whole picture.

You need to find out whats going on there.
This must be either a 1500 truck or a real late rig to have a MAF

The MAF is used to control several things including the EGR. soot in the intake can only come from one place.

Make sure the EGR valve is not all skanked up and stuck open.
Let us know

Robyn

[d2rvk]

My truck is a 1500. i am relativity new to the 6.5. can anyone help me with help with the how the EGR would affect the soot in the air box and the turbo delay.

Thanks

[DmaxMaverick]

The EGR allow exhaust gasses to bleed into the intake, but it should only happen when there is no boost whatsoever. If the EGR valve is stuck open,or opening when it shouldn't, it will increase the amount of gasses (and soot) allowed into the intake. If the engine starts to load, the turbo will spool, increasing the exhaust back pressure. This increased back pressure is released into the intake via the EGR valve. This will cause low max boost, delayed turbo spooling, and really high EGT's, under load. If the MAF is bad, or has soot on it, it will be relaying less than actual (or no) air volume, and can cause the above symptoms. It's a chicken/egg problem, where either one can cause the other. At the same time, your vacuum system needs to be operating properly to allow the EGR and wastegate system to work together to prevent excessive soot from entering the intake, and to keep the EGR valve closed when exhaust backpressure is higher during engine load. Early systems only allowed the EGR to open when there was zero throttle input, but the incorporation of a MAF (and MAP) lets the computer decide when there is a no-load condition, and allows the EGR to open. If you have replaced a vacuum controlled wastegate actuator with a mechanical, the EGR system needs to be addressed to prevent this condition, as well. If the computer can't control the exhaust backpressure (wastegate), the EGR system won't operate properly. A weak vacuum pump or vacuum leak can and will very often be the cause of all the above.

[d2rvk]

So how would you explain the soot on the outside of my air filter to me it is plain to see that the air box is sucking in soot. the soot is concentrated where the gaps in the air box are.

thanks

[DennisG01]

How 'bout a leak between the turbo/manifold mating surface or the turbo/downpipe connection? Couldn't that also account for a loss of turbo performance?

[DmaxMaverick]

So how would you explain the soot on the outside of my air filter to me it is plain to see that the air box is sucking in soot. the soot is concentrated where the gaps in the air box are.

thanks

I don't know. I'd guess it's not soot, but something else. You should have NO soot on the clean side of your air filter. If the filter box is leaking, it could be anything that happens under the hood. If your CDR plumbing is leaking, the oil vapors could be getting sucked in. If your EGR is not closing, the gasses could be getting blown back through the intake duct. I'd have to see it to guess what it is. Post some pictures and we can go from there.

[d2rvk]

I just looked at the egr and am not able to take pictures right now but i did take the vacuum hose off of the egr with the truck running and felt no vacuum. should their normally be vacuum while idling.

thanks

[DmaxMaverick]

If the engine was up to operating temp, there should be EGR vacuum at idle. If the ambient temp is really cold (like in Michigan in January), it can be delayed. It's best to check it after a good run when the underhood temp is up. Check your vacuum pump, tubing, and valves. If a valve fails electrically, it will trigger the SES and set an EGR code. The vacuum pump should develop more than 20" at idle, ideally, 25".

[d2rvk]

A new twist was discovered tonight!! i started the truck with the hood open and found that when i did a little poof of smoke rose from the turbo area. it looks like i have an exhaust leak that would be pre turbo. the question is where could the turbo have a leak and if so where? The exhausts manifold looks clean i cant see exactly where the smoke is coming from i have had a truck with a warped manifold before and that was a loud ticking noise and was really distinctive but this sounds no different. My ses light is back on and i plan on taking it in to the shop soon.

Any thoughts on where in the turbo this leak could be coming from?

I really appreciate all of your input through out this whole thing.

Rick

[JohnC]

Check for a crack in the crossover pipe right at the flange. Hard to see but it'll kill the boost.

[d2rvk]

Is the cross over flange behind the turbo? how hard would it be to replace if it was bad?

[DennisG01]

Ummm...Didn't I suggest a leak about a week ago?;)

The turbo downpipe is directly behind/under the turbo. It's the ~3" pipe going down. The exhaust crossover pipe is attached to the rear of each manifold. You'll see it if you crawl underneath. If the bolts that hold it onto the manifolds are not frozen, it'll take about 10 minutes to get it off.

[daustin]

One of the first upgrades people do to these trucks is replace the factory downpipe with a 3" mandrell bent one. The factory downpipe is very restrictive and looks like it's been run over by the truck. Also another upgrade people do at the same time is a 2 1/2" mandrell bent exhaust crossover. If you search around you can find both of these for about $150 total. Just about all of us have done these upgrades, improves power, throttle response and fuel milage. Hard to beat for just a few $$.
Don

[joed]

Also,

Check your 'donut' seals at the crossover/manifold mounting surface. I've had both sides on mine leak. It's usually pretty obvious, you'll see black soot on the outside around the area. I think these are around $15 each at the dealer.

Joe.

[rustyk]

Is the cross over flange behind the turbo? how hard would it be to replace if it was bad?

The crossover pipe is underneath, connecting the two exhaust manifolds.

[d2rvk]

Got under truck and looked at crossover and donut seals every thing looks fine but when truck starts up up some where by the turbo exhaust is puring out i need ideas. could it be waste gate? does the waste gate dump out?

Rick

[DennisG01]

Can you be more specific to where it is? But, I'm going to venture a guess that you're talking about where the downpipe mates to the turbo? Try tightening the band clamp.

[d2rvk]

I cant really see up there what is the best way to get up in there?

rick

[d2rvk]

Took truck in to the shop last night they told me that it was EGR related. they fixed it today and hopefully it works thanks for all the incite.


Thanks

Rick

[d2rvk]

The shop replaced 2 Egr solenoids and tightened the turbo inlet clamp 3-4 turns

Rick

[DennisG01]

Glad you got it fixed!