Injector Problem?

I have 214,000 miles on that '95 crappy 6.5 engine. Still runs great. Only thing ever replaced were the glow plugs and oil pressure sender.

Guy at work has a 94 I drove the other day has 639,000 miles on it and still seemed to run good. Only down side is it didn't start the greatest but it's got one broken glow plug and the rest are china plugs.

I wouldn't say the Detroit is terrible motor but at the same time I don't think anyone would ever pick it today with what's available out there my ford has over triple the torque but it's decades newer.

thompsoncustom said:

Guy at work has a 94 I drove the other day has 639,000 miles on it and still seemed to run good. Only down side is it didn't start the greatest but it's got one broken glow plug and the rest are china plugs.

I wouldn't say the Detroit is terrible motor but at the same time I don't think anyone would ever pick it today with what's available out there my ford has over triple the torque but it's decades newer.

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When GM quite selling the 6.5L, 96 out of 100 light duty diesel trucks sold in the us were manufactured by someone other than GM. those are numbers even GM could not ignore.
The only reason they are still made is because of the HMMWV, which for parts logistics makes sense.
GEP did do some wonderful things as far as reliability but the Detroit always was and always will be a dog of an engine

Mogman said:

When GM quite selling the 6.5L, 96 out of 100 light duty diesel trucks sold in the us were manufactured by someone other than GM. those are numbers even GM could not ignore.
The only reason they are still made is because of the HMMWV, which for parts logistics makes sense.
GEP did do some wonderful things as far as reliability but the Detroit always was and always will be a dog of an engine

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ya for the engines of that time I think everyone wishes they would have put the cummins in there but I'm sure it was more about money then performance.

thompsoncustom said:

Guy at work has a 94 I drove the other day has 639,000 miles on it and still seemed to run good. Only down side is it didn't start the greatest but it's got one broken glow plug and the rest are china plugs.

I wouldn't say the Detroit is terrible motor but at the same time I don't think anyone would ever pick it today with what's available out there my ford has over triple the torque but it's decades newer.

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The Detroit can do something the new Diesels can’t do… run on vegetable oil and bioDiesel. The lower compression IP can tolerate the higher viscosities that the newer 10,000 PSI IPs cannot.

TOBASH said:

The Detroit can do something the new Diesels can’t do… run on vegetable oil and bioDiesel. The lower compression IP can tolerate the higher viscosities that the newer 10,000 PSI IPs cannot.

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Conversion kits for common rail diesels are all over the place

The new injectors arrived today from Leroy. I'll wait for a day under 100 degrees here in Tx before I get them installed.

I am not so sure I would want the common rail system on a vehicle that needs to be reliable. It hits over 30,000psi and is very tempermental. I know the road cummins have a reputation for reliability...but from experience I can say the fuel system is by far the weakest link.

This thread has derailed but do keep in mind that the 6.5 engine can be purchased nearly complete for $8000. If you get water in the fuel and take out an IP on your 3.0 Duramax you can be out close to $20,000 just to repair the installed engine. Hate the 6.5 all you want because it's not a good drag racer but it makes diesel engines accessible to people they wouldn't normally be accessible to.

Well, this is the closeout for this thread. To recap, the truck suddenly started making a severe knocking noise. In a diesel, assuming you didn't throw a rod or the like, the most common cause is a leaking injector. If an injector leaks fuel into the cylinder on the piston up-stroke, then the fuel self ignites early, slamming the piston opposite direction and causing a sound exactly like someone hitting the side of the block with a hammer. This was my problem.

For others like me, still new to the Hummer, the injectors are short, fat, bulky little buggers. There are 2 vents on the outside of each injector. The vents go from the rear injectors, to the next in line going forward, until the entire side is vented to a hard line at the front of the block. When I say "vent", these are actually where excess fuel is bled out and back to the pressure pump.

Changing the injectors takes a 29mm deep socket. No other tool will work. The "B" fuel nuts require an 11/16" fuel line wrench. The vents have spring locks from the factory, which are a PITA. Chances are they will disintegrate rather than release properly. The rear 3 injectors on the left are easily accessed from the side of the engine bay. The forward left is not accessible unless you remove the huge ass 200 amp alternator, which means removing the serpentine belt. On the right side, the rear 2 are best accessed from the passenger compartment, while the forward 2 injectors will require removal of the coolant overflow reservoir. You could get by working around the huge air filter canister, but it is probably faster in the long run to remove that too. The complete job required about 5 hours.

Leroy sent 8 injectors. Mine for the 2008 1123 6.5 liter are the purple ringed injectors. He also sent new copper washer seals, new vent hoses, and 2 end caps for the rear-most injector vents that have nowhere to go.

The engine runs great now...or at least as good as it ever has. One thing I recommend addressing while changing the injectors is to check your glow plugs. My glow plugs were changed when I bought the truck 2 years ago. I have only put 1000 miles on the truck since then, and ALL 8 PLUGS WERE SHOT!! 4 were totally open circuit. The other 4 had resistance in the mega-ohm range. Much more than the 1-3 ohms for new plugs.

And, "that's all I have to say about that".

Re.: blown glow plugs.

Rebuild you PCB/EESS as per my posted instructions, or purchase a rebuilt or a new unit.

IMHO

You are saying the control module burns the plugs?

I have done a search, but can't find the thread you are referencing...I found a few others where you talked about the thread, but I just can't find the actual thread. Could I get a link to it?

cjd said:

I have done a search, but can't find the thread you are referencing...I found a few others where you talked about the thread, but I just can't find the actual thread. Could I get a link to it?

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I posted… but many others contributed and/or were quoted.

cjd said:

You are saying the control module burns the plugs?

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If the PCB/EESS unit does not cycle properly it can blow glow plugs.

I skimmed through the thread. I commend you on a lot of planning and work. I am more of a KISS kind of guy. If I cannot find a plug and play fix, then I think I may just disable the whole glow plug system. My plugs were burned out for for at least a year, and I had no trouble starting, as we just don't get extreme cold here in Texas.

Your thread was great in specifying connectors and pin uses, which will come in very handy...thanks!

if your looking for plug and play, this is the ticket.