First off, I think this sight is great!!!!! I have a 1995 Chevy 3/4 ton with a 6.5 ltr diesel in it. I'm having cold start up problems. She can sit for 3-4 hours and she starts up hard, she stumbles and blows out white smoke (Can this be the injection pump?). I replaced the pump driver module and all glow plugs and checked the resistance in all her wiring and everything appears fine. I talked to a mechanic. He thinks there is air getting into the system while she sits for a period of time. He suggests I should replace the IP. However, when she starts up and is running, she's good to go. Any help would be very appreciated!!!!! Thank you.

Pump won't cause hard start cold problems, drainback is pretty much an unheard of problem with these trucks. How long do the plugs stay on when you try to start? Does the truck start easier when if you cycle the plugs a couple of times first? How cold does it have to be to give you fits? Is the truck burning any oil? When's the last time you had the injectors out? 100k is about all you and ask out of them before they pretty much turn in to squirt guns, and that will cause white smoke hard start cold condition.

Did you check voltage to each glow plug wire? If a couple are broken, it might cause it.


Does it burn any antifreeze?Edited by: whatnot

Thanks for the feedback. What I meant about cold starts is that when the truck sits for more than four hours it's hard to start with the temps in Wisconsin being between 60 & 80 degrees. It acts like, she turns over & tries to start, but it just chugs for a second and dies. When I try for the second time, she starts & blows out a lot of white smoke. The glow plugs cycle on the first time for about five to seven seconds & the second start up, it just clicks on for a second or two and then shuts off. The truck does not burn any oil or antifreeze, all glow plugs are functioning correctly. It's just the initial startup is bad. Is it possible that the IP could lose pressure & cause air to get in the system? The injectors are original with 133,000 miles on them. Could it be possible for the injectors to lose pressure & leak fuel into the cylinder? Any help is much appreciated. Thanks for your time.

Thanks for the feedback. What I meant about cold starts is that when the truck sits for more than four hours it's hard to start with the temps in Wisconsin being between 60 & 80 degrees. It acts like, she turns over & tries to start, but it just chugs for a second and dies. When I try for the second time, she starts & blows out a lot of white smoke. The glow plugs cycle on the first time for about five to seven seconds & the second start up, it just clicks on for a second or two and then shuts off. The truck does not burn any oil or antifreeze, all glow plugs are functioning correctly. It's just the initial startup is bad. Is it possible that the IP could lose pressure & cause air to get in the system? The injectors are original with 133,000 miles on them. Could it be possible for the injectors to lose pressure & leak fuel into the cylinder? Any help is much appreciated. Thanks for your time.


I would be incline to believe the injectors were bad. You should be able to find a diesel shop that can benchtest them for you after you remove them from the engine. They may also sell rebuilt ones to replace the bad ones.

thanks bowtie, but Could it be possible for the injectors or ip to drainback lose pressure & leak fuel into the cylinder? Any help is much appreciated. Thanks for your time.

thanks bowtie, but Could it be possible for the injectors or ip to drainback lose pressure & leak fuel into the cylinder? Any help is much appreciated. Thanks for your time.



I think that can happen. If you don't want to spend the money right now on a set of injectors, I would at least pull a couple and have them tested.


If you do get new injectors, you will probably want to order them from somewhere. They are $50 each around here (I paid $32 ea. for mine)

The only fuel that could leak past a really bad injector when the engine is off, is fuel that is still in the high pressure lines, which isn't much to begin with, but as soon as you shut the key off pressure in the lines/pump/injectors all goes to nil, so I'd say thats not your problem. Poor chatter quality, atomization, spray pattern and reduced opening pressure is what you will find on your injectors, and the reason it smokes white is the engine can't burn the fuel when its introduced to the chamber like that until it gets hot enough for the smoke to go away, but its still not going to burn like it should.

it is possible for injectors to leak down or drip. I found one once that sounded like a bad rod bearing. Only took 3 weeks of teardown and putting back together many times before discovering it. Someone help me on this white smoke is unburned fuel before combustion I think I read somewhere right.

Yes, white smoke is unburnt 'raw' fuel, which enters the chamber while the engine is running and its because an injector is not properly atomizing the fuel, just sorta squirtin it in there, once the engine gets hot, the fuel can ignite in the exhaust manifold causing a sound like you described and white smoke/miss. But if the injectors are just a little weak, then you won't get a definite miss, just a little white smoke like Shawn is complaining of.

Soo its my injecters that are bad , and not my ip,how much do they cost? and where to buy them.but my truck runs like new when she starts up and warms up.is that possible too run soo good when she is warm? with bad injecters.thanks

When the engine is hot it can burn that fuel thats being squirted in from your injectors easier than when its cool. Double check your lift pump to make sure its running, if its not and your developing a partial vacuum in the supply system you could potentially be drawing air, but if that were the case, you'd more likely have white smoke all the time, stalling and things of that nature, the symptoms your describing to me, if all your plugs are good, controller is functioning properly, and your lift pump is working, you need injectors.

You won't find a better price than this: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7919759035&catego ry=33554

32 bucks a pop, new, Bosch, you better hurry before I buy them ;)

thanks alot Texas Diesel Guy, what is a lift pump and where is it? and how to make sure its working right. thanks

start the truck, unscrew the bleed on top of the fuel filter, if fuel comes out, hits the hood and makes a mess, your good, if nothing comes out and the truck dies, you need OPS or lift pump. Jump the relay in the fuse box to see if you can make the pump work, if you can, then you need a new Oil Pressure Switch, if you can't then you need a new supply pump. The pump is on tucked in beside the frame rail directly below the driver's seat.


- - X


X -


Fuel Pump relay, in the fuse panel by the brakes/ABS stuff. Looking from the driver side fender, will be the one toward the front/pass side of the truck, jump the two pins marked with X's above to test the pump.

Thanks again i will let you know if fuel comes out of the bleeder. I do know that the supple pump is working you can here it run.

Almost sounds like a bad glow plug wire or two to me. I would pull the wire off the glow plugs and put a volt meter on them and run the start cycle on your ignition switch and watch for voltage right at the end of the plug, i'm not sure on the older models but my 2000 glow plug wires are fusable links and number 5 was burnt right off, had to solder in a patch right after my exhaust install as i never noticed it until we had it on the hoist, i new it had a starting problem and just thought it was a glow plug that i'd change before winter. If you had 2 bad wires you'd have an issue starting it cold.