Relatively new here and recently purchased the vehicle in my sig.

Vehicle history - 166,000 miles; IP replaced at 98,000; head gaskets replaced at 155,000.

Like the subject line says, this is a hard starting beast when cold - even with ambient air temps in the 60's and 70's. Warm, it starts without any hesitation. Truck runs fine in all other respects. Changed the fuel filter as a first step in the hard start t-shoot, but it had little to no effect.

What I'm looking for, if there is such a thing is a step-by-step diag procedure, i.e start here, test glow plug by . . . next test GP relay by . . . . then check LP by . . . . Maybe this is something that would have value in a FAQ.

One note. In another forum I read were when testing glows, if a test light lights when connected between the + batt term and glow plug, the plug is shot. In another forum, it was said that given the same results, the plug was fine. Who do I believe?

Barring all else, can anyone recommend a good diesel tech in the metro Milwaukee area ?

As always, thanks in advance.

Here are few questions to start you with:
* Is your service engine light on?
* Do you have fuel coming out your water drain valve while engine is running?
* Do you have white smoke on startup cold?
* Check your glow plug relay connections. If they are loose, they may have melted down and the relay can't make contact anymore.
* Check to see if you have 12 volts AT the glow plug spades during the Wait to Start period. On each side of the engine.
* Check your Ohms to ground on each glow plug (spade to ground) ~1 ohm or less, good, post back results. If open (Infinate) bad plug.

Above, not in order, but good checks.

When you test your Glowplugs, make sure you unplug them and test individually.

You can get fancy with a multimeter if you want, but I prefer just a continuitity tester, if it lights up its OK.

Does your wait to start lamp come on when you turn the key on? If it comes on and stays on for several seconds when cold, your relay is probably good, if it flashes on when cold, then either the relay is bad or you've got several burnt plugs.

If it doesn't come on at all, check the fuse first.

Supply pressure, OPS, thats an easy one, start the truck and while its idling open the bleed on top of the fuel filter, if fuel squirts out its good.

If none of these fix your problem, then you will need to hook up to a scanner.

When you test your Glowplugs, make sure you unplug them and test individually.


Thanks for the clarification there TDG. Welcome to the 2000 post club.

I think testing the Ohms has merit. If it shows .8-1.4 ohms there's enough R to produce enough heat for ignition, but a 3.0 Ohms glow would make half the heat yet still test good on a test light.

I would recommend replacing the glow plugs if you never have. They are not that expensive and 166k on the truck it is due. I replaced mine at about 100k and it made a big differance statring in the winter. Good diesel shop in Milwaukee is Hucksdorf Diesel. I have used them several times for work and personal.

Here are few questions to start you with:
* Is your service engine light on?
* Do you have fuel coming out your water drain valve while engine is running?
* Do you have white smoke on startup cold?
* Check your glow plug relay connections. If they are loose, they may have melted down and the relay can't make contact anymore.
* Check to see if you have 12 volts AT the glow plug spades during the Wait to Start period. On each side of the engine.
* Check your Ohms to ground on each glow plug (spade to ground) ~1 ohm or less, good, post back results. If open (Infinate) bad plug.

Above, not in order, but good checks.

No SES light.

No fuel from drain line when running.

White smoke at startup - Yes

Checked for 12v at the glow plug spades during the "Wait" period with a V/O meter. On the 5 that it could easily get to (4 on Driv Side, 1 on Pass forward of turbo), I DID have 12v at the spade. The other 3 will require a bit of assistance to test.

Got nothing for resistance readings on the GPs. Suspect that the V/O may need a battery or fuse. Will check again.

With the little info that has thus far been reported, can anyone draw any conclusions? Right now I want to lean toward the Lift Pump. Am I wrong?

No fuel from drain line when running.
I'm leaning towards the OPs, can you put direct power to the lift pump while the engine is running and then check to see if you have fuel coming out the 'T' while running? I'm not sure on the procedure for that on the 94. If so the LP is good, time for a new OPs??

you can jump the LP relay like this on a '92-'94 to direct power the LP. OPS is most likely but try jumping first to verify that.
- x -
x . -

I'll add a new twist to this . . .

As I mentioned earlier, I replaced the fuel filter before venturing too far into my cold start problem. Pulled the old filter, cleaned the bowl, added a little diesel to the bowl, slid the new filter in, tightened the outer ring, opened the vent and turned the engine over a few time until fuel came out, closed purge valve.

Tonight on the way home, after having 2 votes of 'confidence' that the OPS was a likely culprit to my problem, I picked one up. Too dark out side to do anything by the time I got home. So, I figured I'd put the truck in the shop so I could work on it tomorrow evening. In anycase, I wanted to see how the truck would start - ambient air temp about 75*F. Truck started quicker than it has, but no where near like it does when warm. Interestingly, while sitting in the truck as it idled, the truck died. Restarted without too much ado, but I could definitely tell that there was a miss - a shudder. Waited for the engine to warm a bit and took the truck for a short drive - less than a mile. Truck studdered and missed like never before. NO SES light though.

What did I do wrong ? Where did I go wrong ? Just for spite, with the truck running, I opened the filter purge to see if fuel would bleed out - no fuel. In fact truck died shortly after opening the bleeder. Closed the bleeder on the filter and truck started again after a couple of lengthy attempts.

I'm getting so bewildered by this truck that I'm about to replace the LP, LP relay, GPs and GP relay - remove all the pieces of the puzzle, if you will, except the IP and PMD. The way it ran tonight, I'm not sure that I could make it anywhere to have it serviced.

Before I close, what the best procedure to get at the OPS? Unbolt the filter bowl and move the 'harness' bracket out of the way ?

Any and all assistance is greatly appreciated.

The OPS is behind the filerbowl and is best removed with an OPS wrench (~$10). Your current problems could be nothing more than fuel starvation.

Sounds familiar. I changed out both the ops and the lift pump and it made a ton of difference.
Mark

The OPS is behind the filerbowl and is best removed with an OPS wrench (~$10). Your current problems could be nothing more than fuel starvation.

QM can you reference a source/part number for the OPS wrench? From what I saw it could be invaluable.

wi65td,

If you were closer I would let you use mine. It can be picked up at auto zone or advanced auto or a KOI for about $6.00. Just go in and ask for the OPS socket and while you are there, ask for the part you already bought and check the fit, then give them the part back and buy the socket.
Makes life a whole lot easier.
Mark

On my truck the socket wouldn't fit because the intake manifold was in the way. Did you guys take your manifold off first or am I missing an easier way? :confused:

Well there is some good news to report.

Got home wit plenty of daylight remaining and the truck in the shop ready to have the OPS replaced. Unbolted the fuel filter housing so that the brakect that holds several connectors could be moved out of the way and thus allow for some vision and room to manuever. Thought about dismounting the GP relay, but decided against it.

Undid the OPS conector, slid the newly acquired OPS socket (Car Quest - $9.60 including WI taxes). Socket was a bit difficult to get on because of some interference by a hose clamp on a vacuum(?) line in that area. None-the-less, I did get the socket on and lthe OPS removed.

Installation was a tad trickier . . . remember the hose clamp ? Well after some minor cussing I was able to loosen the clamp and rotate the head out of the way of the path of the OPS, yet still be able to get to it to retighten. After that installing the OPS was a piece of cake, though it does require a bit of dexterity and some contorsions.

Wrapped everything up and started the truck. Now keep in mind that when we last left this saga the truck was running rough (shuddering and sputtering) after changing the fuel filter. Well after running with the new OPS after a couple of minutes the shuddering and sputtering went away.

Backing up to a couple of points made during the diagnostics phase, with the new OPS installed I now have fuel at the T-drain and can here the LP running momentarily after shutdown. Neither was the case prior.

Tomorrow AM will be a truer test. A true cold start with the new OPS. More news at eleven (AM), as they say. But so far things look promising.

BTW, I did order a set of GPs from Kennedy today. Figured I'd be safe rather than sorry come winter.

To those that provided input - MANY THANKS !!!

Sounds good, just make sure you bleed the filter base too. The draincock is great for checking fuel pressure and taking fuel samples, but the bleeder on top of the filter is the only way to get rid of any air trapped inside.... good luck.

Wi65TD;
I put the JK quick heat on my truck and the glow cycle wasn't long enough to start was well as with the OEM plugs (9G's) I put the SS Diesel Glow Plug over ride kit in and now I press the button when the glow plug light goes out and get more glow time and she starts real nice now.
http://dieselplace.com/forum/showthread.php?t=27954&highlight=Glow+plug+ride+kit

Sounds good, just make sure you bleed the filter base too. The draincock is great for checking fuel pressure and taking fuel samples, but the bleeder on top of the filter is the only way to get rid of any air trapped inside.... good luck.

TDG, explain 'bleed the filter base', please. Did I miss a step in changing the filter - remove old filter, clean filter bowl, fill with duel, install new filter, jump LP or crank engine with top bleeder open until fuel comes out steady, close top bleeder, and away we go . . . .

Couple things to point out for ya:

When changing glow plugs, all are fairly simple with the exception of a couple on the pass. side. Be sure to remove the heat shields prior to removal and installation so you don't break a wire and thus allowing easy access to the plugs(while going through the wheel well).
Second: whith the age of your truck, when removing the filter bowl or even changing the t-stat(and removing the "T" bleeder valve), be careful with the fuel hoses. I found out they become very brittle in age and can split causing fuel spillage and truck shut down. This by experience and changing the fuel lines from the filter bowl to the "T" bleeder valve can be a real PITA when you do not want to remove any of the upper parts.
Just a thought.
Mark

TDG, explain 'bleed the filter base', please. Did I miss a step in changing the filter - remove old filter, clean filter bowl, fill with duel, install new filter, jump LP or crank engine with top bleeder open until fuel comes out steady, close top bleeder, and away we go . . . .

wi,
I think what TDG means. is when you get the truck running open the "T" also so that you will remove any crud/crap that you could not get to while cleaning out the bowl(after you close the valve on the filter).
There are items caught up down there where you can not get to when cleaning out the filter bowl. Again, this is from experience.
Hope this helps.
Mark