I'm trying!

[cleatus12r]

Diesels ARE my speciality. However, the 6.5L has left a bitter taste in my mouth. I actually have a guy here that has souped up his '98 with injectors, an intercooler, aftermarket turbocharger, etc.

He just put a new long block in it since he blew the last one up (go figure ) and now the dang thing just won't run worth a crap. White smoke (unburned fuel) at anything above an idle. I can't advance the injection timing enough to even do the TDC learn. The marks on the pump and the front cover are 5/16" off (advanced) and it still needs to go more. I told him to pull the front cover and see if the timing marks on the cam and pump gear were lined up. He said they were. I was out of ideas.

Any thoughts?


Dang I love electronically injected diesels.

[ChuckD]

Thats why I like the 6.5 in the humvees.

[BlackSTX]

Funny thing Cody, we had a guy with a similar issue a few weeks ago. Had an new/reman engine done and is now having a similar issue... white smoke. Also says it's runs like a gas engine which is too rich; seems like it loads up at idle, but if he gets it up to speed and hammers on it a bit, it clears up. We're scratching our heads at this too. He insists that the mechanic who tested the compression for him says it's good on all cylinders, however we suspect he may be losing it somewhere accounting for the white smoke, though the timing issue you mention seems like it could also be something to consider.
My understanding is that if you have the compression it should burn, and additional fuel will give you black smoke..... However, if you're injecting fuel past TDC or too late, I imagine it could lead to this condition; that seem correct?

When I worked at a Chevy dealership, we had a local fleet with loads of 6.5L naturally aspirated trucks. They were bringing in an average of 2 trucks a week with knocks, or rods out the side. Most of the trucks were all near 100k and '93-4 models too, if I remember correctly.
One of our truck guys said the 6.5 is a good motor, but most people either lug them or wind them up too high, too often, and it will kill them quick.

I'll check you situation with the owner where I work, he's the one ask, he's worked on them for years. Perhaps with what you have come across it may shed a little more light on the problems both of our customers are having.

[907DAVE]

Grrrrr........GM 6.5's are fun. They use to have a BUNCH of those they used on the north slope for the pipeline guy's, and they have been slowly trickling down to us for years. Not many left but there still around. Got one in the shop now with a cracked block(not again). I cringe every time I see one in the lot waiting to get fixed. And I LOVE diesels............... just not those.

[BlackSTX]

Originally Posted by cleatus12r

Diesels ARE my speciality. However, the 6.5L has left a bitter taste in my mouth. I actually have a guy here that has souped up his '98 with injectors, an intercooler, aftermarket turbocharger, etc.

He just put a new long block in it since he blew the last one up (go figure ) and now the dang thing just won't run worth a crap. White smoke (unburned fuel) at anything above an idle. I can't advance the injection timing enough to even do the TDC learn. The marks on the pump and the front cover are 5/16" off (advanced) and it still needs to go more. I told him to pull the front cover and see if the timing marks on the cam and pump gear were lined up. He said they were. I was out of ideas.

Any thoughts?


Dang I love electronically injected diesels.

Here's what I learned about getting this thing set up. Using Tech2 to disable the stepper motor you can then get it to learn TDC. Any movement of the crank sensor will require it to be relearned. Disregard any marks on the pump or cover.... as I was told: "They shouldn't be there, they were probably made by someone at some other time." I scratched my head at that too, but after looking at a reman pump we had, there were no marks on it. (?)
But the owner said if you have any questions you're more than welcome to email him, he's happy to help out. Walt, the owner, responds to all tech questions personally, and usually responds to questions within a day. http://www.ssdieselsupply.com/contact.html
Just be sure to include all the info you have about the truck and what this guy has done to it, the tech form asks you for this too.
Walt is a good guy, very knowledgeable, and like Bill, doesn't believe in selling you something he hasn't proven to be a benefit. Drop him a line, I'm sure he can help you figure out what is going on with this guys truck.