'83 K5 Diesel Surges

[bduff509]

I have a 6.2L diesel in my Blazer that surges rapidly whether it's cold or warmed up. If you run it up just a little past idle ( I don't know how much, no tach) it smooths out. Anyone have any idea what's going on? Thanks.

[BlazerLT]

Ever replaced your fuel filter?

[bduff509]

Both fuel filers & air filter.

[BlazerLT]

check your timing advance and you might want to run a bottle of marvel mystery oil through the tank when you fill up next.

[bduff509]

I'll look into that. Is ckecking the timing something that I'm going to need a service manual for? I've never dealt with a diesel before & the truck Chilton manual I have for that era don't mention that engine. I've been told I should run some Seafoam through it also. The trouble with running anything through it right now is that it's not on the road & only runs periodically.

[Jeremy Fitch]

Do you know exactly what engine is in your truck, as in who made the engine and what model? Sounds like it may be an injector issue to me, maybe even a fuel pump. Most diesels have 2 fuel pumps, One is an injection pump which is a high pressure pump that sends fuel to the injectors, the other is a lift pump that gives fuel to the injection pump.

[bduff509]

All I know about it is it's a stock 6.2L. I wasn't aware that there are 2 pumps on it but someone had suggested to me that it may be the pump. Another guy told me I should just raise the idle to stop the surging. I thought I'd better ask around a little more.

[Jeremy Fitch]

Originally Posted by bduff509

All I know about it is it's a stock 6.2L. I wasn't aware that there are 2 pumps on it but someone had suggested to me that it may be the pump. Another guy told me I should just raise the idle to stop the surging. I thought I'd better ask around a little more.

You might try posting over at
www.gm-diesel.com they would be able to give a lot more info than you would get here as the specialize in diesel engines.