Waste gate on 3176 Cat

Mick & Denise

Mick & Denise

New Member
Mar 26, 2008
208
Eastern NC
Boat Info
1996 50 ft Sundancer
Engines
3176 Cats 600hp
Ongoing problem with lots of smoke and no power between 1100-1400rpms untill the turbos kick in. Mechanic told me to check the waste gate. I cannot even find it in the manuals. Does anyone know if this is on a 1996 year 3176Cat engine? If so what does it take to check it out? Thanks for any advise.
 
I thought diesels don't have waste gates. What mechanic told you that? If it wasn't a diesel mechanic, get another opinion from a Caterpillar guy.

Best regards,
Frank
 
Diesels sure do have waste gates. If it's stuck open, you'll experience a power loss just like you describe. It's possible the shaft is frozen up or there is a hole in the diaphragm.

Doug
 
I had the same problem once and indeed it was the waste gate. Was not something for a do-it-yourselfer though.
 
I will look for it downstream of the turbo unit. The mechanic is a very well know diesel guy in this area so I tend to with his recommendation of checking the waste gate. Doug, I do not know their function yet but will check it out. Bluebelly, I am not glad for your problem but its good to hear you had the same problem and it was the waste gate. Another dealer was telling me to replace the injectors and software to run them and the replacement injectors were $422.00ea. plus the software and re-programming. So, I am hoping it's the waste gate. I will let you guys know and thanks again for the advise, Mick
 
The waste gate is basically a flapper valve that limits the amount of pressure or boost that your system will take. As exhaust gases spin the turbine and ultimately the compressor, more and more boost is made. Once the compressor reaches a predetermined limited (this can be adjustable as well to make more power), it is bypassed via the wastegate valve. If the valve is stuck open or the diaphragm has a hole in it, the compressor will not make boost and your engine will be sluggish and low on power.

Doug
 
Frank, There is a big electronic box on the side of the engines that about 30 or so wires go into. All the manuals I have that go with this boat have all kinds of diagnostics for the computer end of things. I did just pull out the boost pressure sensors and they were not dirty at all. I still cannot find the waste gate. I have had a lot of fingers point to that but if its on these motors it is hid well. This is getting very frustrating as you can imagine with any problems.
 
Ive got 3196 cats in my 560. I am going to my boat this weekend and I will check for the location of the wastegates.
I personally don't believe these cat engines have wastegates but I will let you know in a day or two. I have had semi tractors for years with cat engines and personally rebuilt a 3406b and they never had wastegates.
Anyway I'll let you know.
Jack
 
I don't know the 3176 Cat engine personally, but every turbo diesel I've seen had a wastegate. Some wastegates are an integral part of the turbo though. Check on the turbo housing itself.

Doug
 
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Another thing that could be causing your issue is excessive clearance between the turbine and the housing on the exhaust side.

Doug
 
Thank you all for the advise. It certainly is giving me some things to check out. There was no sign of this problem 6 hours ago of running time. Is that something that wears that fast? I did pull the air filters off and reached down in and the turbos seem to spin nice and free. One other thing I have noticed is that the turbo's seem to be kicking in at 1650 instead of 1450 like they used to. But still have not found the waste gate. Does something need to be taken off to find them? Like a exhaust line off the turbo?
 
I was on my boat today and searched the engines for wastegates. On my boat they don't exist. I have 3196 cats.
I know they used wastegates on gas engines to keep them from taxing the engine too much but I've never seem them on a deisel. A diesel(as I understand it) RPM is controled by the Injection pump which limits the high rpm. Anyway I'd like to know what you find out.

Jack
 
earthmover17 said:
I was on my boat today and searched the engines for wastegates. On my boat they don't exist. I have 3196 cats.
I know they used wastegates on gas engines to keep them from taxing the engine too much but I've never seem them on a deisel. A diesel(as I understand it) RPM is controled by the Injection pump which limits the high rpm. Anyway I'd like to know what you find out.

Jack
Click to expand...

I did a little more research on this issue tonight because I am still perplexed why you couldn't find the wastegate. I finally came across a thread that answered my question....

1. Most turbo diesel applications for the automotive world do in fact have wastegates. Check any diesel truck site and you'll see threads upon threads with information regarding this.

2. Some engines in non-automotive applications run without wastegates because they have a narrower rpm operating range vs. a typical automotive application.


So apparently some turbo diesels do exist without wastegates, but again, all the ones I've seen do have them.

Doug
 
My 1996 500 with 3176's did the same thing. I have heard from several guys on boatdiesel.com that also have this problem and nobody has fixed any of them them yet.
They all have a similar experience. Most of the them have 500 Sundancers. I emailed Sea Ray and they said nobody has this problem.
I had CAT come out and update the software, check for codes, and recalibrate the throttle position sensors. (Yes Frank, those engines are all electronic)
We plowed down the lake while his laptop told us and CAT through a wireless modem that everything was just fine.

No smoke at idle. No smoke on the top end. Just a long, long, long, long, long, wait for the turbos to come on. and lots of black, overfueling type smoke while u wait.
Once you make it to 1500rpm, all of a sudden it takes off like a rocket (if you get there) Then the exhaust cleans up and the boat runs just fine.

Sound familiar?

As you accellerate everything just stops at 1300. Between 1300 and 1500 there is no power at all. My boat was pristine, low hour, fresh water, and propped correctly. 2350 at WOT

The CAT guy told me that this engine has a "large turbo option" and that is how they are.
I can't believe it ever left the factory like that...........
But, there are quite a few guys out there with this exact boat and this exact problem.

What you really need is an experienced and honest CAT tech who is used to working on boats and has been around for a while.

CAT and Sea Ray both say there is no problem.

If you get yours fixed, I would love to know what it was.

I sold the boat, bought it back, and sold it again for this very reason.
If you eeeeaaasseeee into the throttle, it seem to like that better and smoke less.

Mine did it steadily for almost two years. I actually had the spare props cut down a bit to unload it some in the mid-range but I haven't put them on yet for the new owner.
 
I'd be very suprised if your diesel engine does not have wastegates. Typically, they are mounted near the turbos turbine (exhaust) housing.

My Sea Ray has the Man diesels. Althoug this is my first year with the boat, I noticed in the springs (with 45-50deg water temps and non-humid 50 to 65deg air temps) the boat came up out of the water at a good pace.

Now that the water temps in the bay are ~80-85deg, its really humid, and the air temps are 80-95degrees it takes the boat a full 30 seconds to go from 1200rpm to 1600rpm. Once the boat hits 1600rpm, the turbos sing and she'll spling shot between 1600rpm and 2,350.

Similarly, she smokes much more now that's its hot vs. earlier this year when getting up onto plane, and then the smoke goes away once she's up on top of the water.

Everything I can see (oil, filters, temps, pressures, etc.) check out 100% on the engines. So I thinks its fair to assume this is normal with the summer heat and humidity which knocks the power out of turbo'd engines... When guests ask what is going on I just tell them "the black smoke is what barreling through $200.00 looks like" as I wait for the turbo to kick and throw them back into their seats :grin:
 
Boatingfool said:
I'd be very suprised if your diesel engine does not have wastegates. Typically, they are mounted near the turbos turbine (exhaust) housing.

My Sea Ray has the Man diesels. Althoug this is my first year with the boat, I noticed in the springs (with 45-50deg water temps and non-humid 50 to 65deg air temps) the boat came up out of the water at a good pace.

Now that the water temps in the bay are ~80-85deg, its really humid, and the air temps are 80-95degrees it takes the boat a full 30 seconds to go from 1200rpm to 1600rpm. Once the boat hits 1600rpm, the turbos sing and she'll spling shot between 1600rpm and 2,350.

Similarly, she smokes much more now that's its hot vs. earlier this year when getting up onto plane, and then the smoke goes away once she's up on top of the water.

Everything I can see (oil, filters, temps, pressures, etc.) check out 100% on the engines. So I thinks its fair to assume this is normal with the summer heat and humidity which knocks the power out of turbo'd engines... When guests ask what is going on I just tell them "the black smoke is what barreling through $200.00 looks like" as I wait for the turbo to kick and throw them back into their seats :grin:
Click to expand...

Have you ever had your turbine clearances inside the housing checked?

Doug
 
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From turbo car experience a waste gate is a servo that opens a reliefe valve on the pressure side of the turbo once a preset boost level is reached thus "wasting" the extra boost. This can be a small can looking thing with a rod coming out of it attached to a lever on the actual valve. Again I have no knowledge of diesel operation but figured I could help you locate where the wastegate is for investigational purposes!
Here is a link to a wastegate that should resemble the one on your engines, if so equipped.
http://www.jscspeed.com/srt4/turbo/agp_wga.htm
 
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