Sorry y'all had to post another one because the others i've searched didn't seem exactly the same. First off, I've go a 95 7.3 w/ 170k on it. Supposedly the PO replaced all glow plugs but I have not verified that. Yesterday when I started it it blew much more blue smoke then usual. Ran fine all day but when I went to start it for work today it cranks and blows alot of white smoke which I'm assuming is spent fuel...? Anyway there was alot of fuel in the filter housing and I can hear the relay clicking on. That's as far as I've gotten. This is my very first diesel so any help would be much appreciated, I am lost. Thanks. Oh also is there an easier way to check each plug w/out removing the valve covers and having to replace the gaskets?

 

Yes, white smoke is fuel, just cold fuel. Glow plugs really don't go out as often as everyone thinks they do. Most of the time it's the relay. Even tho you can hear it click, that doesn't mean it's working. Check it with a test light. As far as checking the glow plugs with out removing them, I don't think you can. The valve cover gaskets are reusable, unless they are cracked or the plug shorted out and melted.

 

Verify that the gpr is working and check the hpop res before starting.

 

The glow plugs draw around 20 amps each, take a inductive amp clamp and measure the amp draw from the relay, you should see 160 amps initial draw then it will taper down some, you can check each side of the engine by attaching the amp clamp to each side and measuring the amp draw, if two glow plugs are bad it will affect the starting of the engine considerably,
The wiring under the rocker covers goes bad as well as the glow plug plug ends, you can repair them as there are kits available to do so, i personally would replace the wiring as any repair wont be a lasting repair.
If the glow plugs check good the white smoke may be caused by worn injectors and or low actuation pressure to the injectors, this engine uses a huei system which over time will give you problems, the huei pump / injector pressure valve fails as well as the injectors,
A weak engine oil pump/ worn oil pressure relief, which is a gerotor design pump can also give a hard start as the oil pump supplies the huei, the huei needs a strong flow of oil so it can feed the injectors with the correct pressure to fire,
As the miles accrue things wear some, any leakage in the oil system will hamper this engine to start and or run smooth, emit white smoke etc,
The fuel system can also cause problems, that engine uses a mech plunger style fuel pump which has a high failure rate, low fuel pressure will cause hard starting and white smoke, usually when they fail its end of story and your engine quits running period, the pump sits behind the air horn and the turbo down in the V of the engine, real pia to change. You can check for a lose fuel line, seen them get lose at the pump and the fuel filter housing, air in the fuel can also cause similar problems.
I will mention low compresson as i hope this isnt problem, but yes a low compression from worn piston rings will cause a starting problem and white smoke,
If your a pretty savi mech i can walk u through the different tests to pin point the problem, if not find a trustworthy diesel shop for troubling shooting / repairs.
Regards Rich

 

you can also test your gp's with a continuity tester at the uv wire harness plugs. you have 2 plugs on each side, and I believe it is the middle 2 terminals on each plug that go to your glow plugs. test for continuity to ground. A bad gp will not have continuity.

 

It's the two outside pins for each plug... They should be within .6 and 6ohms...

 

Thank you for the correction there 95powersmoker, I was looking at that in the book this morning.

I was looking for the same reasons, I am not sure why mine died yesterday trying to leave the driveway. Does anyone know what hpop pressure should be on cranking? seems it would have to be more than 100 psi right? I am going to yank the ipr tonight and see what it looks like, but am not too optimistic. I am already pricing hpop's.

I don't mean to steal this thread, but being that we all have the same problems with these things from time to time, maybe we can all work together here and get her figured out.

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btw, we are talking about the good stroke in my sig

 

You want about 500psi for the HPOP.

 

that is about what I was thinking I needed to make fire, but it has been a long time since I checked that out on my other psd. Also if I remember correctly, it will spike to about 2600 psi on initial start.

being I am only getting about 100 psi on crank, and about 400 psi on a false ether start, do you suppose that my hpop is done? or maybe just my ipr is plugged? It started fine up until yesterday, then quit like you just turned off the key. hpop is stock I think, w/ about 205k on her. Is that how they go out?
on a side note, I get absolutely no smoke on crank.

 

HPOP's usually don't just decide one day to stop working. I'd be suspect of your IPR...They are fairly sensitive. There is a link around here to clean your IPR...

No smoke on crank is because your injectors aren't firing.