Turbo Woes

[AKMark]

Hello everyone.

I'm having a few issues with the Turbo on my 97 K1500. I've owned it since December and even though I've ridden in many vehicles with the 6.5L before, had not noticed that I didn't hear any turbo whine with this one at all. It wasn't till I rode in another at work and heard the spooling and found one more to compare with that I realized what was missing.

So I've been doing some testing. The vacuum to the valve, is good. The valve moves as it should. Unless the flapper it controls is bad, it's doing it job.

The turbo spins nicely. It's not too dirty, and doesn't have much play. I pulled the air line leading to it off and started it up and it spins like one would expect. However when the engine speed is increased, I didn't notice any difference in the Turbo's RPM's. I didn't notice any leaks from the intake or lines from the turbo to the intake. I pulled the sensor out of the intake to check for boost pressure, and got vacuum instead.

So needless to say, it seems as though my turbo is shot. I'd rather not spend $600 for a new one, and the cheapest I've found one used is $350, at least it was a -8.

Does anyone have any other ideas to try? I'm pretty handy with wrenches. I've rebuilt two 6.2's, several 350's, and a few other motors and have converted a few trucks to diesel as well. I found a rebuild kit for my turbo for $65 with shipping, but after seeing it operate tonight, I'm not sure it would help.

I should note this truck has 197K, so it might be time to change the turbo and be done with it.

Any and all thoughts are appreciated, as long as they aren't trying to convince me to throw a 454 or Cummin's under the hood. (I have friends that think I'm made of money, even though I prove often how I'm not.)

Thanks in advance!

[rhsub]

Are you getting any black smoke on acceleration, if the turbo isn't working it will smoke like crazy, the turbo in my 99 is very hard to hear but I checked it with a scanner and it is working properly, try removing the lid off the air cleaner and road testing, the new style air cleaner (cylinder shaped filter) is much quieter than the square filter. To check boost remove iat sensor (brass colored sensor screwed in upper inake plenum) and hook pressure tester to port, make sure iat sensor is still hooked up to harness or you will set a code, old style fuel pressure guage will work for this test, road test, if no boost run a vacuum line directly from vac pump harness to wastegate vac diaphram and recheck for boost. This should give you full uncontrolled boost under load so don't overdo it. Make sure the wastegate rod is contected properly and moves freely
Good luck
Ron

[Robyn]

If the Turbo spins freely and has little play then its OK.
The turbo should spin very fast as soon as the engine RPM is increased some.
There should also be a fairly noticeable sucking noise at the turbo inlet.

Check to make sure you dont have any restrictions in the air inlet to the turbo and also be sure you don't have any restrictions in the air plenum assembly going from the turbo to the manifold.

Now this said, if there are no issues here you need to check the exhaust system.
This truck has a catalytic converter in the exhaust system and if this gets plugged up the engine cant breathe.

The Cat can be removed to test this issue.
If you dont mind a little smoke and noise you can unhook the downpipe from the turbo outlet and fire the rig up to see if things work better.

Check inlet for restrictions
Check exhaust for restrictions (Cat and the muffler as well as connecting pipes for kinks or?????)

There should be no vacuum in the manifold on a diesel.
A vacuum gauge should not read unless there is an issue

Keep us posted

Robyn

[AKMark]

Couple of things noted today.

Crawled underneath and the downpipe from the turbo looks like it's got several dents heading down to the pipe where the cat and muffler connect. So that's probably not good.

Other item to note, after getting home from the commute (10 miles) the Cat was cool enough that I could touch it briefly with no issues. On all my gas motors (never had a Diesel with a cat before) the cat is so hot you cannot even think about touching it without hurting yourself. So that makes me think it's time to do some exhaust work.

The crossover pipe looks like crap as well.

Guess it's time for a new exhaust system, huh?


I guess I should have mentioned that the reason I'm checking this stuff out is that compared to other 6.5's, this one seems rather gutless.

[JohnC]

A stock 65. with stock intake and stock exhaust doesn't make much turbo noise. None audible from the cab while driving is not surprising.

The definative test is a boost gauge. Nothing else matters.

Turbos will not generate boost when the engine is not under load. There just isn't enough exhaust heat available.

[AKMark]

I towed a truck on a trailer last Friday, and noted that my old 91 with a 6.2L pulled about the same as far a performance goes.

So I definately have a problem somewhere.

This Burb doesn't smoke at all, no matter what I seem to do.

Anybody have a recommendation for type of exhaust?

[AKMark]

I've been looking at Warpspeed exhaust, diesel performance systems, and Jerry Jardine engineering stuff as well.

All three have similar prices and products. Anyone have a favorite?

I'm going to remove the exhaust from the downpipe and see if it makes a huge difference, to verify if the Cat is clogged.

[AKMark]

Okay,

Ran a few more tests.

Pulled the four nuts at the downpipe. I made a plug to go in the aft section of exhaust and put a pressure guage, regulator, and air line on it. I was able to put 8 psi in the exhaust before it started to finally push air through. It remained at 7 psi after that and every time i cut airflow, it took 8 psi to get it flowing again.

So, it seems as if the Cat is clogged.

With the exhaust still disconnected at the downpipe, I took it for a drive. HOLY COW! I went on a seven mile drive that had several steep inclines. Speed limit here is 50 mph, so it's running OD with the torque converter unlocked. It went up every hill without shifting, and took much less throttle to hold speed than normal. Also, when it first started up, it idled close to 1100 rpms, normally it is no more than 800 when cool. The idle settled down after about thirty seconds and took another minute of till it was at about 600. Which is normal after idling for a minute. After my little drive it was 450-500, which is also normal when it is warmed up. I'm guessing it idled high initially because it was turning easier than normal and it needed to rethink how much fuel it needed to idle. The turbo is definately spinning efficiently now and I seem to be getting much more power. The rumble from the downpipe is a bit much for regular driving, but okay for the moment.

Anyway, I'm going to replace the entire exhaust from the Turbo back as the downpipe has seen better days. I mentioned a few earlier, any suggestions?

[Bnave95]

http://www.kennedydiesel.com/categoryresults3.cfm?Category=2&SubCategory=66&SubCategory2=18
And my Bank's Exhaust been on for 10yrs.
So more than likely,The best system will be your last.

[mrwilecoyote]

As was said before I'd say 99% sure your turbo is fine. Few things. One the factory vacuum system that controls the boost sucks. It rarely works right and when you need the boost the most is when it seems to fail. My recommendation is a Turbomaster mechanical wastegate controller from Heath Diesel . as far as Noise on a 97 I "Believe" yours has a turbo muffler. Look by the hose coming off the intake and going to air box. if there is a funny looking useless plastic pipe that seems to go nowhere that is to keep your turbo noise down. if you want to hear spool up more lose it . I rubber freeze plug works well in it's place. The soot trap(it is not a cat even though it looks like one) may be required in your state for emissions (see your in Cali)so I'd check into that before spending booku dolores on a new system. You could always do what I did and remove it gut it and put it back. your truck will thank you and your MPG will probably improve as well as egts go down. I highly recommend a boost gauge. I prefer autometer full sweep but there are plenty of low cost ones that work fine. It's the only way you'll know for sure what's really going on.

[AKMark]

Thanks for the info.

Cali doesn't require emissions on Diesels, and it's getting registered in Alaska (I'm military and moving back there as soon as I can)

I now have a boost guage on order, as the Turbo seems to operate fine without the soot trap or Cat on it. It was plugged, had an exhaust shop take a look at it. They also recycled it and gave me credit, enough to replace it and fix the exhaust. It should be fixed later this week, they couldn't get it in right away.

The muffler has leaks and massive dents, so it's gonna get replaced as well.

I'm hoping to convince the wife to let me get Heath Diesel's wastegate control. I like the sound of it and will get it as soon as I am able.

THANKS for all the info!

[More Power]

Okay,
So, it seems as if the Cat is clogged.


These oxidation catalysts (cats) are not lifetime parts. They need to be replaced every few years, depending on how the vehicle is driven, to reduce the level of exhaust backpressure restriction due to soot plugging. A light-duty soccer-mom/grocery getter will plug a cat sooner than a hard working 3500 series truck. It all depends on the average exhaust gas temperature over time. The climate also plays a part. A cat equipped diesel will plug sooner in cold climates than warm climates, especially if driven locally more of the time. Again, it's the average EGT over time. The cat has to reach soot combustion temperature once in a while to keep it clean.

Well-equipped exhaust shops or garages can drill a 1/8" hole in the exhaust tubing before the cat, install a pressure fitting, then measure the exhaust backpressure while the vehicle is accelerated. The hole can be welded closed after the test. 1-3 psi would be normal for the 6.5. My guess is that yours was generating more. Good job on tracking the problem down...

Jim

[Robyn]

You have many options.
The Turbo master is a nice unit but I recommend pairing it up with a Chip from Heath that will allow the extra boost without tossing overboost codes.
The Banks Stinger system is a nice way to go and is easy to install.
Check with Kennedy diesel and see what he has in ready to go stuff.

For a quicky you can make up a "test" pipe to replace the CAT and do some testing.

This sort of restriction is very tough on the engine as temps soar when you work the engine.

best

Robyn