lift pump?

[TheDodgeMan69]

I have a 92 W350 w/281k. About a year ago, my truck was having a hard time starting and would slowly dips up to the normal idle rpm and didn't have much power. I replaced the fuel filter and nothing changed. I then tryed to move the mechanical arm on the lift pump and would not move. I replaced the pump with a stock pump from Genos. My truck is starting to thave a slight sputter as I start it. It only lasts for a second, then runs fine. It has lots of power still. I replaced the lift pump almost a year ago. The fuel filter has 10k on last change. The transfer pump only has 7k. I don't have a pressure gauge to test it. Could it be going out already?

 

[JLEONARD]

I had a lift pump go out on me after about a year or so. The two rubber diaphrams inside the pump had partially disintigrated and they would no longer seal on their orifices.

 

[cerberusiam]

Either that or the fuel lines are developing cracks.

 

[roachcoach]

I agree on the fuel lines, if a little air would happen to get in the line it would make the truck sputter for a little bit until the air was moved out by fuel.

 

[NIsaacs]

With the colder temperatures, it is not unusual for high milage injectors to slobber a bit when first started.



Nick

 

[DVolk]

You might check to see if the KSB is working or not

 

[roachcoach]

With the colder temperatures, it is not unusual for high milage injectors to slobber a bit when first started.



Nick

This is true too, but he said it only does it for a second. If it would happen to be injectors I would expect the sputter to last a little longer, say maybe until the truck would warm up.

 

[HHhuntitall]

It's been my experience, unless it's REALLY cold, the low idle and first stutter is related to partial fuel prime loss. Air entering the system when it's shut off is usually the culprit. I'd bet there's a diesel leak somewhere on the pump, and it's either siphoning back into the tank from the cracked line or leaking externally on the pump itself... .....

 

[cerberusiam]

It's been my experience, unless it's REALLY cold, the low idle and first stutter is related to partial fuel prime loss. Air entering the system when it's shut off is usually the culprit. I'd bet there's a diesel leak somewhere on the pump, and it's either siphoning back into the tank from the cracked line or leaking externally on the pump itself... .....

Yep, a stutter is usually air in the fuel path somewhere. A slobbering injector will just haze on startup not cause cylinders to drop randomly.

 

[TheDodgeMan69]

When I first start my truck, engine worm or cold it barley starts. After it starts it barley idles. Like the idle is to low. I tank the throttle pedal and it goes back to normal idle. I think part of the problem is the linkage that the pedal and cruise control is attached to is really worn. When my pump got turned up, we didnt use the original idle screws. We used the throttle rod to adjust the idle. With the linkage badly worn, it lowers the idle. Are there rebuild kits for the throttle linkage or a replacement? When try to start it after sitting all night it does seem to crank longer, like it isn't getting fuel for the first 20-30 seconds of cranking. I have no noticeable fuel leaks that I can see. My cold weather advance doesn't work, hasnt worked since I've had it.

 

[HHhuntitall]

Ahhh, ok. Well, if you have the linkage adjusted to hold the idle, then yes, your problem is there..... but that's why there is an idle screw from the factory. YOu should be able to adjust it up to where it will make it idle properly... ...

 

[TheDodgeMan69]

Any ideas on replacing or rebuilding the throttle linkage bracket? Anyone?

 

[TheDodgeMan69]

I found a replacement throttle control bracket at the Cummins dealer. It comes with the whole bracket, spring, clip, washer, bushings, the bracket that the pedal and cruse control cables attach to. I payer 35$ plus tax. Cummins part number 3918457. Thanks for all the help.

 

[HHhuntitall]

Alright! Thanks for the part number!

 

[Bluebird]

Lift Pump from Cummins...

Just my $. 02. When I replaced my lift pump some time ago, I got it from Cummins. It cost a little more, however it's still working .



Happy New Year, Patrick

 

[TheDodgeMan69]

I replaced the throttle linkage bracket and no change. It seems to be cranking freely before it starts to catch, like it has air in the line. I checked for fuel leakage on the fuel supply line, no noticeable leaks. I didn't see any leaks in the return line either. I'm going to replace the fuel lines with rubber fuel lines. I checked the lift pump and it is working. Could my injector pump be getting weak? Once it starts, it runs fine, lots of power, no noticeable smoke or noises. The truck has 282k miles on it, with the original injector pump.

 

[TheDodgeMan69]

I replaced the fuel supply line and no change. I don't know what to do now. Any ideas?

 

[JLEONARD]

Did you ever try bleeding the injectors before trying to start? Not that you should have to, but you might find a leak doing that. That is also how I learned my lift pump was going out... the injectors didn't have much pressure during the bleeding process.

 

[TheDodgeMan69]

I will try that and report back.