Engine/Transmission (1994 - 1998) Intermittent ticking noise

[SmokinU]

Hey guys,



My truck recently developed an intermittent ticking noise. Since I bought my truck, I've always noticed a steady ticking noise coming from the fuel return line. But this ticking noise is different. It has no rhythm to it. Sometimes you hear it, and some times you don’t. The noise does not increase with RPM. The noise is loudest on the drives side of the engine. There is no change in performance, fuel mileage, or drivability.



The truck was making the noise tonight, so I revved it up, and when the rpm's came down, the noise was gone. This one really has me stumped.



Any ideas as to what this noise is?



Brandon

 

[britannic]

When you hear the noise, is it half engine rpm or full - this fact may help in isolating the cause?

 

[CumminsPower98]

The only ticking I get is from my lift pump. It also comes and goes and is not consistent at all. You might want to double check this. Also the overflow valve can tick I hear but mine never has. If it's not RPM specific then I don't know.

 

[SmokinU]

Thanks for the reply guys. It can’t be the overflow valve because its new, but my original guess was lift pump. I guess I'll have to check fuel pressure to see where I’m at.



Brandon

 

[britannic]

Just a word of caution: YMMV, but "new" doesn't always mean it works properly, I installed a new lift pump, that was DOA recently. I'm learning to double check the obvious to eliminate the impossible.

Originally posted by SmokinU

Thanks for the reply guys. It can’t be the overflow valve because its new, but my original guess was lift pump. I guess I'll have to check fuel pressure to see where I’m at.



Brandon

 

[CumminsPower98]

I replaced my lift pump to get rid of a ticking problem and it helped a lot but even the new one still ticks now and then. It really ticks me off, LOL. My cousin's '97 never ticked, old pump or new one. Anyway I have seen plenty of parts new and rebuilt that were faulty out of the box.

 

[Andy Redmond]

If you replaced the overflow valve, the old one was soft and allowed for subpar fuel psi... Once it's replaced fuel psi is up making the lift pump work a bit more. I've overstreched a overflow valve spring in a field repair for temporary service and observed this tick, especially with more than 30 psi at idle. Once the psi returns to 20-25 at idle it became more quiet. I then disassy. it and compressed the spring a bit and it was better. The spring will re-collapse over time likely, so the new part is the fix. Bottom line, a new lift pump will likely minimize the tick. We don't want to let it go, if its "slapping" the camshaft, 'cause then we could cause some wear on the cam that strokes the piston pump.



I've also has a new lift pump and overflow valve tick a bit with none fuel psi, volume etc. . adn assuring the camshaft was scarred up by the previous lift pump. . maybe the nature of the manf. tolerances.



My . 02 Andy

 

[drrhoades]

How much is a new lift pump?

 

[Andy Redmond]

Cummins 165 +/-? DC a bit more?