I posted this at another forum on the net but this one seems to have some extremely knowledgeable people so I might be better posting here.


I have a 93 Silverado 2500 4x4 with a 6.5 turbo diesel. 199k miles.


This is my first diesel and though I am quite handy on a gas engine, this diesel thing is extremely confusing. So please be as descriptive as possible!


I was driving today and noticed some sluggishness/loss of power while driving. It was intermittent but then again my drive was only for about 10 minutes. I stopped at the bank and turned it off.


20 minutes later, I came out and went to start it. Nothing but a worn out battery after 15 minutes of trying to crank it.


8 hours later after leaving it in their lot I came back and tried to start with some jumpers. This time the glowplugs came on and I got a slight start with an abrupt stall, and could not start it anymore after that. So it is still sitting there and I am towing it out in the morning BUT I HAVE TO FIX IT TOMORROW!


I have noticed it is VERY tempermental when it is warm, and sometimes I drain the battery trying to start it. Usually when the plugs come on though it fires right up, but I don't know the relevance as this time it did not start like it usually does.


Where do I start????? I thought fuel filter or MAYBE a fuel pump but usually when a filter goes atleast in a gas engine you don't get a complete shutdown, just sputtering/stalling or lack of power.


Thanks for ANY advice you can offer.

Diesels are much more sensitive to fuel filter pressure drop than gasoline engines. I would start there.


Since we're dealing with a 93, it must have a mechanical injection pump. Worn injection pumps are known to have hard hot start problems. May need an IP rebuild.


If your glow plugs are intermittent, you may have a bad glow controller...also a known failure item on the mechanically injected engines.


Others please chime in. Good luck.

I'm going through some of the same.
starts fine cold but get it hot and try to start it and it just cranks with an occasional slight start.
The only way I can start it at this point is to jump it and even then sometimes it plays hard.
I have totally examined the fuel system for leaks with the lower manifold off today and found nothing.
I noticed that if I dumped water on it sometimes this does the trick.
guy with a 6.5 who saw me cranking and listented to the symptoms thought I needed to wire a momentary switch on the glowplugs because he thought the tempature was keeping them from warming enough to start.
I'm putting the glowplug relay off my other truck on to see if it helps.
one more thing, sometimes it starts weak and you can hear it's going to stall.

The early DB-4911 inj pumps cause hard warm-starts due to excess clearance in rotor\head, where fuel pressure can not develop to 'pop' injectors.


Was a Stanadyne revision - improved rotor\head assembly - about same time as DS-4 fixes, with new Blue Label\Green Tag indicating 'fix'.


Early pumps had black label.


Hi-mileage injectors, unable to atomize the fuel, also play a role in hard starting.


Hi-mileage being anything over 70kmi - GM\Stanadyne\Bosch specs.


Hi-milege Blue Label pumps, with worn transfer pump, will hard start.


Low battery voltage, corroded cables, loose connections, worn starter bushings\bearings\brushes playd a large part, where inj pump was not at fault.


Transfer pump filter screen could become clogged, reducing fuel supply.


This is easily cleanable, with intake manifold removed - remove fuel supply line, remove locking tab, unscrew round housing\cover, and screen is visible. Usually stainless, can also be polyester, or some such plastic.


CAUTION - take care not to disturb transfer pump ring and blades


Inspect for rust while open, indicating problems resulting from water in fuel.


In instances where vehicle is seldom used, Diesel fuel 'sours' - bacteria, moisture, etc - causing hard starts, cold and hot.


And, as ronniejoe stated, fuel filter (and air filter) plays a larger role in Diesel engines - do not discount these as source of problems.

Truck has all glow plugs and cycled for 8 seconds cold.
It cycles for only 4 seconds hot.
'93 relay didn't fit due to wireing
Since everything else is working I'm going to replace it to eliminate it's being the problem.
and I just had water in fuel and injectors are 70,000 miles old.
starts on first crank anytime it's cold.

Warm engine does not need as much glow as cold engine - glow times are shorter.


Functional engine should warm-start with no glow - ~375psi cylinder pressure across all eight cylinders.


Necessity to increase glow times would indicate injection problem, where injected fuel is not being atomized, either from slow cranking, deteriorated inj nozzles, worn inj pump, stretched\worn timing chain and sprockets.


Iirc, was a directive to advance mech timing each 60kmi to compensate for chain stretch.