Engine/Transmission (1998.5 - 2002) Intermittent Lift Pump - Help!

[DStauffer]

Hi All,



I've been lurking here for a couple days trying to solve the non-starting truck (1999) issue. After reading all I could find, here's what I've got...



The lift pump is only getting voltage about 1 in 15 key turns. When it gets voltage, it pumps about 45 oz or so of fuel. As one thread states, that's about right. The truck actually started once when the pump got voltage.



I've read enough to feel comfortable changing either pump if that's what the problem is, but it doesn't look like that now. It appears to be electrical.



I'm looking for the "next step". Should I look at wiring, relays, ECM or what? And, how would I troubleshoot those items?. I have the service manual, but I know there might be better resources or knowledge on this board. Any help or direction on what to try next would be greatly appreciated.



Thanks for the help I got reading so far and thanks in advance for help here now.



Dave

 

[CCutshaw]

Pull your LP relay and reset it could very well be a bad connection.

Calvin

 

[nps]

Do what CCutshaw said. It is located in the PDC box under the hood on the drivers fenderwell.



If that doesn't work, then the relay itself could be bad. Check its control input at the relay socket with a multimeter.



If the relay is not getting a control input, then the ECM or wiring between the ECM and relay is bad.



If all else fails you can wire the LP to a switched and fused 12V source and run it when the key comes on. This is how I run my pusher pump.

 

[DStauffer]

Thanks for the suggestions. I think wiring past the ECM and directly to the pump is the best and cheapest fix.



I was looking at the service manual and it says that the Fuel Relay in the PDM is only for gas engines. I had it pulled, turned the key and the pump ran for a while. The diagram shows the pump wired directly to the ECM. I played with the wires and pushed all the connectors in and the truck started and ran a couple times, but not every time. The battery was low so I had to quit for the night while it charges.



Once, while the truck was running it faltered and the tach dropped to zero. Hope this is a symptom of the same problem, but with my luck, it's not!



I will get a switch and wire power directly to the pump tomorrow night.



Thanks again,



Dave

 

[Gary - K7GLD]

Once, while the truck was running it faltered and the tach dropped to zero. Hope this is a symptom of the same problem, but with my luck, it's not!

That's often a symptom of a bad/failed Crankshaft/camshaft position sensor (CPS)

 

[steved]

Sometimes the lift pump won't run when you initially turn the key on depending on how warm it is outside... every CTD I have worked with has done this...



The only thing you could do is make sure the LP is getting voltage all the time (instead of guessing it is a voltage thing) and verify that the LP is good... the symptoms you describe (about the LP) are exactly how my dad's first LP failed... it would work when it felt like it...



As for the no start/intermitten start, sounds like a bad VP44... have you checked for codes??



steved

 

[DStauffer]

Insert red face here... I have AutoTap ODBII code reading software and interface cable installed on an old notebook. I bought it for my Jeep several years ago and haven't thought of it since. I will drag it out tonight and see what I get. Will probably have to update the software. At least it comes with free lifetime software updates.



Should have thought of this before.



Thanks,



Dave

 

[DStauffer]

Here is an update...



I couldn't get the code reader to connect, I needed to get the truck running, so I took it to the Cummins dealer (33 miles away).



They found the "speed sensor" broken in half. They said they had to pull the starter to get to it. Charged me $600 for everything.



I can't tell, from a quick look in the service manual, what they mean by a speed sensor. Do they mean crank or cam position sensor?



Truck runs fine again.



Thanks for the information all. I learned quite a bit about the fuel pumps from reading around in these forums. So when it does go bad, if I can properly diagnose it, I feel I can change it myself no problem. Still working on getting the Autotap ODBII reader to work.



Dave

 

[steved]

I believe that is either the Crank sensor or Cam sensor... one is hidden behind the starter.



steved

 

[Honker]

Dave,

If they pulled the starter on your truck, it was the crankshaft position sensor that they replaced, part #4921601 price $38. 91. Price they charged you seems high to me unless they replaced the tone ring on the crankshaft to. Part # for the tone ring Ring, speed indicator is 3942441. I was just curious if tone ring was replaced as I ran into this problem myself.

Bob

 

[DStauffer]

Nope, they didn't replace the tone ring. Here is the invoice...



Cause

Engine speed sensor failed

Correction

(shortened up... shop stuff)

Troubleshoot - ISB, Active fault code No. 115

Engine speed sensor - Remove and install

Remove and reinstall starter

Drill out broken engine speed sensor in block

Engine - Chassis dynamometer diagnostic check

Part 38. 91

Labor 548. 80

Misc 33. 70



I really couldn't be without the truck any longer. It seemed high to me, but it was 33 miles from home and not drivable. Didn't want to borrow my friend's truck & trailer to bring it back. Also I was and busy with other stuff this week, so it wasn't high enough to scare me off. Oh yeah, I was also feeling LAZY!



I lost my tach last year once and the engine ran crappy for about a mile or two. Happened about a week later and didn't do a thing for about 6 months or more till it just wouldn't start one morning.



Dave