6.5 liter chevy engine

[mayt]

I just bought a 94 chevy 3500 dually with the 6.5 liter turbo diesel engine. It has supposedly 110,000 miles on it. It starts runs and idles great. The problem is it has no power. Driving down the road and hit a hill at 55 or 60 and having to gear down to 3 gear no power. We are going to change the fuel and air filters but I just don't see that being all that is wrong. I have talked to others and of course I have gotten different ideas but most say it is the fuel pump and that these engines had a lot of problems with that. Anyone know or had one? I'm a shade tree mechnic and can work on it except for the PCM stuff. Any ideas would be helpful. I.m not really a chevy diesel fan and this is the first I have owned. Tell your stories good or bad. As always your help is greatly appreciated. This is a great site I use all the time.

 

[c felix]

if filters do not fix it check the lift pump fuel pressure.these engines had horriable probles with the hi-pressure injection pumps failing.there are many good re-mans to be had hope this helps.

 

[Anonymous-0]

You may find the turbo is shot,do you have a way to check boost?

 

[Randy S]

Mayt,
I own a 94 GMC with the 6.5 turbo and wouldnt take anything for it.
I have had some problems with it over the years but what your describing sounds to me like (from experience) your muffler and catalytic convertor are stopping up.
At 300,000 miles i had to have mine removed and am running it now without either, just a straight pipe, and its very little louder than before. Once i discovered they were stopped up the diesel mechanic told me that gm had a lot of problems with this and stopped installing the catalytic convertor on their diesels after 95.
Mine has more power now than when it was new. All ive done to it mechanically is to put ALL new berings in it and change the driver box on the injector pump a couple of times. I did buy a heat sink and install the driver box on top of the manifold so it (driver box) would run cooler.
It now has almost 340,000 and is still running better than new.
You will have to change the lift pump every couple of years but to me thats kinda like changing the fuel filters.

I hope this helps and good luck.
Randy

 

[Gene S in IA]

I have 92 6.5 turbo. One time I noticed a lack of power. I replaced the air filter and it really made a big differance. I think these trucks have a undersized filter and they plug up fast

 

[Anonymous-0]

You need to get a boost gauge, my opinion is all diesel engines need a pyro and boost gauge to efficiently run it. Could be low boost. Easy to check if the wastegate is working is while it is running try pulling on the arm on the turbo. Will flop around when not running and be almost impossible to pull when running.

 

[Mathias NY]

A buddy of mine just bought a suburban with the 6.5 Turbo. He had a similar problem, he changed some kind of boost control solenoid. Before the truck wouldn't get out of its own way, if you mash down on the throttle at highway speeds it would dump black smoke, but not really accelerate. Now, it will get out of its own way and actually accelerate. I realize this is a vauge description, but it could help.

 

[bradk]

The waste-gate vacuum actuator or solenoid may be shot or the arm is hanging up. ~brad

 

[bison]

The 6.5 is a good engine,but mostly designed for fuel economy,and not power in stock aplication.
to get the most out of these engines you will need to do a fair bit of tweaking here and there.
My best advice i can give you is to go to the websites

www.Thedieselpageforums.com or www.dieselplace.com/forums.

There you will find all the info regarding the 6.2 and 6.5 and how to get most hp and torque out of them.+ lots of maintenance and diagnose tips.
I could give you some ideas but it would take me 2 days to tell.

 

[dlplost]

Sounds like the turbo isn't working. there's a valve that controls the turbo, it may be stuck or not working. I have a 97 3/4 ton 4x4 with 220,000 miles and get 20 mpg, with plenty of power.

 

[Luke S]

It really depends on what you are going to be doing with it in regards to if you will be happy with it or not. I have always been a Dodge/Cummins fan. About a year ago I had a guy come into my store looking to sell a truck. He had a really sharp and clean looking 98' Chevy 3500, extended cab, 4x4, leather and all, 6.5 diesel and only 50,000 original miles on it. I all ready had two good Dodge's but I thought, what the heck this is a nice looking truck, so I bought it off him. I figured I could use it for light towing (10-15,000 lbs), I then looked in the owners manual and noticed it said max towing for that truck was a measly 7,500lbs! I did a lot of studying at the diesel place website and the general consenus was if I hooked it on to 10-15k I'd be craking heads and overheating. This I did not understand having had Cummins for all these years and pretty much pulling everything I have hooked on to and never had any of those kind of problems. Long story short, I got scared and sold it to some guy who thought it was the greatest thing ever, and I guess what I am saying is if you don't pull heavy they might be ok, but they are darn sure not my cup of tea. I'd rather have an old 454 Vortec over a 6.5.

 

[Anonymous-0]

We ran 1 of those over 300000 miles with no problems of any kind. Kept the filters changed. Boss traded it for a dodge with diesel. Nothing but trouble,. Even the UPS trucks pass this darn thing.