Engine/Transmission (1994 - 1998) Got Problems Cant Figure It Out.....

[DPulis]

at my work we got a 98 12valve ctd

manual transmission etc got 89,000miles

some days she can start easy some times she starts hard she will crank hard, fire , then stumble for a couple seconds then die then you can turn it over again it may do it again might not depends on what it feels like doing but after you get it started she runs great but then if you shut her down for a few minutes then try to restart some times it will start hard almost like the fuel pressure bleeds off then after a couple of starts she fires stumbles then picks up and runs fine..... im puzzled??

I replace the fuel filter every 3 months just replaced it again, primed the lift pump a million times to get her started then it just keeps doing it any one have an idea?? any help would be good... .

 

[BNH4221]

DPulis



Check the fuel return lines? Sounds like they may be letting air in the system. Plenty of reading about it if you do a search.



Good luck



Steve

98 QC 12v

 

[JGK]

Steve's idea is good. I'm wondering if the overflow valve is weak and letting too much fuel drain back towards the tank.



-Jay

 

[RHARVEY]

I heard somewhere that you can see if the overflow valve is working by pumping the prime plunger. If you hear either a hissing noise or a popping noise coming from the pump. . the over flow valve is working...

I would check for cracking in the return line. .



Rick

 

[Joe G.]

Does it start ok if you give it a little pedal? If so, your idle may be too low.

 

[BNH4221]

I replace the fuel filter every 3 months just replaced it again, primed the lift pump a million times

While I'm at it, do you fill the filter with fresh diesel before you install the canister? Crack the screw on top of the filter housing? I only have to hit the primer 8-9 times before it bubbles out of the little fitting on the top.

Heckuva messy job but makes priming easier.



Just a helpful suggestion.



Steve

 

[Joe G.]

It's NOT a good idea to pre-fill the filter. That fuel goes to the injection pump unfiltered. Someone on here has advised putting some pressure in the fuel tank with the bleed valve open to make priming easy. I haven't tried that yet, but it sounds like a good idea.

 

[BNH4221]

Joe G,



I am by no means an expert, but after almost 170000 miles I have yet to have a problem. Plus, DPulis has a 12v so pressurizing the tank ain't gonna work.

In a perfect world it would be smart to put the filter on dry with all the attendant effort. I, personally, don't live in a perfect world and am willing to take the risk.



Just my nickels worth (Inflation you know)



Steve

 

[Neibe]

I put my filter on dry everytime and then I push the hell out of the priming bulb. Till I hear a hissing then I give it a lot of pedal when I start it runs rough for a couple seconds this way and then smooths right out. 150,000 miles of doing it this way.

 

[Joe G.]

I haven't tried priming with pressure in the tank on my '95 yet, but it should work. There are only three little check valves in the lift pump to overcome. Even if the pump piston is compressed because the push rod is on the high part of the cam it should work. I will find out the next time I change my fuel filter. I might, just for a test, try it sooner than that. My curiosity is up now.



A 12 valve may start without priming the system anyway. I'll have to try that and see. When I cleaned the chipped paint off my injector lines I had them off and on my work bench. When I put them back on they were as clean and dry as it is possible for them to be. I tightened the nuts on both ends of the lines. The owner's manual says that if you run out of fuel it will start with a little cranking so I decided to try it and see what happened. I ran the starter for 15 seconds maximum and let it cool off. After the starter cooled I tried it again. It started after about 10 seconds of cranking. Lots of rock and roll at first until all the cylinders joined in. A 12 valve lift pump will really move fuel.



We may be exercising our thumb for nothing.

 

[mechanic]

Does it start ok if you give it a little pedal? If so, your idle may be too low.

Joe G.

Just wondering what the fuel plate did for or to the fuel economy? I am thinking about installing one in my 94 2500 to pick up a little power for heavy pulling. I have thread on the board asking others what their experience has been.



mechanic>>>David L 94 2500 2 w/d auto 3. 54 no cat or muffler, nutered kdp.

 

[Joe G.]

It has no affect on MPG. However, a heavy foot because the truck is more fun to drive can have a real affect on MPG. It depends on how you drive it. The proper name for a fuel plate is full load throttle stop so that can give you an idea of why.

 

[mechanic]

It has no affect on MPG. However, a heavy foot because the truck is more fun to drive can have a real affect on MPG. It depends on how you drive it. The proper name for a fuel plate is full load throttle stop so that can give you an idea of why.

Thanks for the come back Joe. I know that my problem would be keeping my foot out of it, but at least I would have the option, now I just push it hard and wait for it to go.

I think I will go ahead and try it.

Thanks again, mechanic >>>David L