Here's the path I'm on, my 94 powerstroke is not wanting to start cold. If I plug it in for a couple of hours it will fire right up. I bought it with this problem, it had a new solenoid installed when I got it, before that the previous owner said he put new glow plugs in it. I started with testing the rack, I had one plug that was not connecting and one of the glow plugs was registering open on the ohm meter. I put a new plug on it and fixed the internal harness. This got it cranking but still had a little miss, so ran the rack again and found another plug with burnt in two. I fixed that and the truck ran perfect for a couple of days, then it got a little miss back. I pulled every plug down and there are no breaks, tested glow plugs every one showed 0.01 and 0.02 on 20k ohm setting. Solenoid is working perfectly, got power to the head, glow plugs reading good, what the H. . . . . Plug it in for hour or two runs fine, let it set for twleve hours and it hits every second or so but if it starts it 'll run real rough til it gets in the normal range on the temp gauge. I'm loosing my mind, now I just drive when I have to (which is about twice a month). I'm getting fed up, maybe you guys can see something I overlooked, I'm about ready to dump it and just cut my losses. BH

 

How cold is it where you are? What grade oil are you using? You said its a 94, is it a 94.5 powerstroke or a 94 idi?

When your talking about a miss is this only when the motor is cold? does it go away when everything warms up?

Also the solenoid your refering to is this the GPR (glow plug relay) that is working fine? Also are you replacing the glow plugs with motorcrafts? I hope your not using autolites.

 

Sometimes you can have a perfect GP system but still not have power to all the GPs because you have one or two corroded Pins for the under valve cover connections. the external plugs at the valve covers is where I would look for your problem. It is an easy check for 3 of the plugs, the fourth plug is under the intake hoses and the need to be removed at the turbo, but make sure you check them all. My money is on the back pass side pin.
- - - - - your pins look like that inside the plug outside two are for the GP's and the inner three are for the injectors, middle is common other two are respective per injector. Check all connections for corrosion. I was able to clean mine up scraping with small screw drivers and then I "adjusted the female pins tighter to ensure a better connection. that has lasted me 18 months now with no problems.
good luck

 

It's about 60 deg here, I use Rotella 15w/40, 94.5 powerstroke, misses when cold, run good (not perfect) when warm (pulls my tractor fine but not as well as it did for that week it was running perfect) solenoid is fine, I didn't replace the glow plugs/previous owner did before I bought it (called him a while back to insure he replaced them, he assured me that they were new ? brand)


Inner connection is good or ohms would read open, I pulled every female pin to ensure they are good. I quess my only possibility now is the pin to plug exterior connection or another set of glow plugs ( ? these tested good)

 

(click here) that gives you a completely new gp system - the relay

Both the male and female connections can burn up. I would bet the gps are fine you just have a burnt harness

 

relay to valve cover is connecting fine, valve cover in is testing same. I'm thinking connectivety is bad between external plug and valve cover pins. I guess I can clean them first and if need be pull the valve cover and check current at the glow plug itself.

 

what are the symtoms of problems with bad oil

 

Bad oil? too many mines on it? Normally a rough idle

 

yeah, maybe I wasn't clear, but that is where I guess your problem will be, on the back pass side external plug, With the down pipe right there you have a little more heat, I have fixed three pins that were corroded at the same plug, on different trucks.

 

If the glow plug system is functioning correctly, it could have some injectors that are sticking when cold. The spool valves in the injectors can stick if there has been a lack of proper maintenance (i.e. oil changes) in the past.

You might try changing the oil and filter if there is any question about when it was changed last.

 

I had the oil changed and have put about 500 miles on it since then. When I crank it up I can get to level out, but It revs up real slow and has to clear a bunch of smoke before I can drive it off. It doesn't actually run perfect until it gets up to the N on the temp gauge. Does that help narrow it down at all?

 

You may need to check the injector poppet specs , or for a loose poppet screw , also.....

 

Sounds like injs need gone through, the poppet valves have worn down into the body too far. You can check by doing a buzz test, if they sound very quiet then they need rebuilt.

 

Are you sure power is coming thru the relay? I know you said you replaced it but it still may have electrical issues controlling it or powering it.

 

Had the same issues you did, changed everything and still no start. It turned out that the terminal end connections on the relay were corroded, cleaned them up with 400 sandpaper and coated them with dielectric grease and for 2 years now no issues. Its a real easy thing to check, just wish I had done the easiest thing first instead of digging into to valve covers.