Engine/Transmission (1994 - 1998) hard starting

[bmoeller]

How are the grid heaters themselves?

 

[Piston Slapper]

I really don't think it is the grid heaters or PCM. These engines don't even need them until it gets cold out. It ain't cold out yet. Still sounds like loosing prime to me. Heard here many times about rubbr lines loosing prime. Leaking enough to suck air, but not leaking enough to loose fuel. Commons sympton is setting for 24 hrs + then hard start. Check them lines good or just replace them rubber ones. It's cheaper than a PCM.



Good luck and let us know...

 

[rjones]

The grid heater arent even coming on when I first turn the key on and the grid heaters test ok... ... . pcm not trigering the solinoids... . obtw i checked fuel lines already and they look good no cracks or checkering no signs of leaking... ... i have to crank it over bout 20 times in the mornings it fires stumble and a ton of white smoke comes out then its fine the rest of the day.....

 

[illflem]

I think you're barking up the wrong tree on the grids. I know here in normally colder than anywhere else in the lower 48 Montana mine haven't had to come on yet.

Still think you have a fuel line problem.

Is it hard to start with a full tank?

 

[rjones]

Hi bill the reason im checking the grids cuz it dont even engage when i turn the key on shouldnt it engage before startup when first turning the key?..... it does it no matter how much fuel is in the tank..... it will turn over start, stall then I have to turn over 15 -20time, starts to stumble i give it some pedal and then it fires with a ton of white smoke... .

 

[Piston Slapper]

Originally posted by rjones

it will turn over start, stall then I have to turn over 15 -20time, starts to stumble i give it some pedal and then it fires with a ton of white smoke... .

Still sounds like a fuel delivery(loosing prime) issue. Start then Stalls... sucking air, stumbles... sucking air, fires and belches if you give it pedal... . over coming the air in the lines by giving it more fuel than it can burn, ie... the smoke.



I don't think the grid heaters will engage unless the ambient temperature is below "X" degrees anyway will they?



We are really just trying to help.

 

[rjones]

Originally posted by Piston Slapper

Still sounds like a fuel delivery(loosing prime) issue. Start then Stalls... sucking air, stumbles... sucking air, fires and belches if you give it pedal... . over coming the air in the lines by giving it more fuel than it can burn, ie... the smoke.



I don't think the grid heaters will engage unless the ambient temperature is below "X" degrees anyway will they?



We are really just trying to help.

Oh I know you are... ... Im just trying to sort this stuf out... I guess Ill crawl back under the truck and replace the return line ill just use rubber all the way back..... is there anyway I can pressurize the line to see where its leaking?... ...

 

[illflem]

You can pressurize the lines by pressurizing the tank, no more than 10 psi though. Just use a blow gun and a rag in the tank fill. It will take two people as the pressure will creep down fast. You won't get an air hiss to lead you to the leak but may get some fuel to leak.



The grids don't come on until the temp inside the air intake drops below 50°.

Until the outside temps start getting much colder your engine can easily hold enough heat to keep from dropping below 50° when parked overnight. Until it gets into the upper 30s you can skip the wait to start entirely and your engine should fire right up.

I don't usually wait for the wait to start light to go out until the first hard start reminds me that it finally getting really cold out.

 

[Dennis Garrett]

When one of the two relays quit on mine, I had to order a new set. I temporatily attatched both grids to the post on the one remaining good relay, and that one relay heated both grids with a little extra wait time. I think you could take the grid leads off the relays and jumper them directly to the pos. side of the battery just to see if they heat up, & to see it it starts any quicker. If it doesn't, then it's definately not the grids.

 

[Cooker]

I agree the grids are not likely your problem. Mine have only come on once twice so far this fall (or late summer).



When you turn the key on they do not come on unless, as illflem mentioned, the air intake temp sensor reads less than 59 degrees. The brief moment the light comes on in the summer is only to test the lights.



I think you should be looking at fuel return line, a burnt up fuel heater (this is more common that you might think), or possible a bad lift pump.

 

[JohnE]

Cooker;

Good point on the fuel heater. Many times they can be the source of a fuel leak and let air in the fuel delivery system.



rjones;

After you try to start the truck and it stalls, get under the hood and push on the lift pump primer button. See how long it takes for the overflow valve to squeal. Anything more than a couple pumps is a good indicator you are loosing prime in the fuel.



Sometimes it takes a long time to peel an onion (troubleshooting).

 

[Howard Durand]

To test the continuity of the heater grids, make sure they are not energized, then connect an ohm meter between the grid terminals and ground. It should indicate a dead short.



As to the rubber fuel hoses, when I changed out mine there was no indication of leaks or cracked lines until I removed them. The only cracks I found were at the ends of the tubing where they slipped over the metal lines. Looking directly into the end of the tube, it looked like the cut end of an old log with radial cracks all the way around it. The outer jacket surface of the lines showed no cracks at all.

I was having the same problem that you descrilbe. Hard starting after the truck sat over night.

If yours have never been replaced, I would guess they should be by now.

 

[rjones]

Well guys thanks for all your help Im letting the truck cool down a little and going to pressurize the system from the tank like bill said wish me luck... ... it looks like a major pain in the arse... .....

 

[rjones]

Results of what I found... While at work today I took my old fuelcap drill a hole in the center and put a air fitting in it so I could pressurize the return system heres what I found... I use 10psi in the tank let sit for 10-15 min came back followed the lines from fuel tank to pumps and I saw fuel dripping on the lift pump felt around it was coming from the water sensor... so replaced it naturally Cummins gave me the wrong sensor must be for a newer truck plug was different but I used it anyway... . so when I get up tommorow morning Ill see if that was the problem... ... . what do you guys think is it possible that it was that easy... ... OBTW the return line under closer observation has been replaced ... ...

 

[JohnE]

OH yes. Many times it is very simple and relatively obvious after the fact.

 

[illflem]

I'm betting you've found the problem.

You never know when using pressure to check for leaks since the only portion of the delivery system that is under pressure while the engine is running is in-between the transfer pump and injection pump, which includes the filter and WIF unit.

All other parts are operating either under suction or very low pressure. Putting air to those parts and you could find a leak that you wouldn't have under normal conditions.

The fuel heater is a good example, it's on the suction side and doesn't take well to pressure, that's why I suggested keeping it under 10 psi.



I use the rag and blow gun on the tank method to fill the filter and bleed fuel after a filter change.

Just open the bleed screw on top of the filter, takes about 15 seconds, heck with the manual pump. Now you've got a better set up for doing it.

 

[Cooker]

Was the water in fuel sensor cracked or did it just have a bad o-ring?

 

[rjones]

It had a bad wire in it I think it was coming from there..... but naturally Cummins gave me the wrong sensor it had a different style plug, I used it anyway, Ill have to buy the right one later... .