I'm a Ford 7.3L woman myself, but I'm posting for a friend and hoping y'all can point me in the right direction.

This is a 1984 GMC 6.2L with OEM but aftermarket turbo. Will start cold....and then you had better not turn it off and think you'll want to be going anywhere again for 4 hours. Don't be taking this truck to the grocery store for milk and bread.

Various people vote for oil in the starter or fuel injector issue.

Can you FTE folks

1) Diagnose the problem even in this other species of diesel?

2) Send me to the FTE forum equivalent for GMC diesels?

PS. I had no idea GMC built these. But I did see a diesel Jimmy on a bar stool (diesel pump) next to my truck when she last went drinking. Apparently the military put diesels in these. Given the body of a Jimmy and the applications of a diesel engine, it makes no sense to me.

Many thanks!

 

GM came out with these for awhile. They were in trucks and cars and suburbans and blazers.

In the Army I drove many on truck and blazer form.

Don't have the slightest on your issue as I never worked on them though.

Maybe it is the pump loosing its prime till cold?

 

I believe Chev used a DB2 injection pump, same as the early Fords. What you described is common with a well worn injection pump.

One way to tell is to drive the truck till warm, shut off for a few minutes. When it won't start, pour warm water over the injection pump (just warm not cold or hot) If the truck starts after that, it's the injection pump.

Now the bad! Because of the close tolerances, cooling the pump with water "may" cause internal problems. The pumps are considered a medium wear item changed between 100-150 thousand miles although many have gone much farther. Performance drops, mileage drops, problems develop, blah blah blah!

 

This is an incedibly common problem with our 6.2s, 6.5s and 6.5 turbos. If you do the water trick as suggested and it works there is your problem. The good news is that you do not need to change the whole pump. You can take the top cover that has the electrical lead going into it off and replace just that part. We change at least 2 a week and that turns the 3+hr job into about a ten minute job. I will see if I can dig up a part number for the solenoid somewhere.

 

Ok the solenoid I am talking about is the fuel shut off solenoid. It is under the top cap of the Stanadyne DB2 and DB4 fuel injection pumps, this is what the 6.2 series GM diesels use. They are found in all military blazers and pickups as well as all Humvees. The DB2 being a mechanical trans kickdown, DB4 electronic. The solenoid is the same for both pumps. I however do not have any part numbers for a 12v solenoid only 24v. Im sure that you can find them in somewhere. I will keep looking sorry to post early just got excited that its a question I'm sure that I know the answer to . What happens is that these solenoids get hot then stick in the closed position tuning the fuel off to the pump.

 

Many thanks for "defecting to GMC" for a minute to help my friend.

I admired the industrial mudflaps on her truck, but took no notice of the GMC until I learned it was a diesel. Then diesel loyalty prevailed and I offered up the services of FTE.

My friend is all psyched about this thread and printed off your suggestions/instructions this morning.

Many thanks, FTE brothers!

 

Did you get anywhere with it?

 

thanks sarge.

 

Thank you sir for your kind words it means a lot.

 

If you are still having problems or for any future problems check out dieselplace.com/ there are pretty good about coming up for ideas on GM's

Good Luck,

Tugs

 

Thanks, brothers.

My friend has other farm projects that have taken precedence. You know how that the To Do list gets fubared on a farm. I will update you when she gets back to the sick truck.

 

Did you ever get any where with this.

 

Don't know if it causes this exact problem or not- but a failing PMD is very common to these trucks also. I'm sure Sarge can explain that POS too. lol

 

I second that. I also like your signature, and the reference to standing behind the troops. I spent 4 years in the service (US Air Force), and have always regretted not staying in longer.

Jim