Engine/Transmission (1998.5 - 2002) What the heck? Truck got A LOT faster out of nowhere.

[Intelman34]

I picked up a 1999 2500 CTD 4x4 with 45k miles about a month ago. From 0-55 the truck had very good WOT acceleration. After 55mph at WOT, the truck would feel like it is pulling fuel. The RPMs wouldnt increase... actually dropped sometimes, and speed would BARELY increase. If I would just accelerate normally up to freeway speed (what fun is that), the truck would have no problems. Also, once in OD, it was able to gain speed, but it was reluctant to downshift... even around 45mph.



Yesterday I changed the engine oil (Delo 400) and filter (Stratapore) along with the fuel filter (Fleetguard). After about 30 min of letting the truck spit and sputter to get running, I took it out for a drive and after letting it warm up, I got on it. To my suprise it downshifted and the truck pulled like never before. So I took it to the freeway onramp and from 0-75mph the truck just kept on pulling without hesitation.



The old fuel filter did not appear dirty so I am not exactly sure why the truck is acting so much different.



I dont have a fuel pressure gauge yet becuase I am not sure what all need to have it in the truck. (I'd like to get the Westach from Genos but I have no idea if thats all I need).



All in all, its definetly a nice change. With my only mod being the Napa BHAF, I need all the power I can get.



Does anyone have an idea why the truck may be acting different?



Thanks!

 

[jrandol]

try cutting open the fuel filter to see whats inside. sometimes outside views are deciving, there could be a ton of junk inside the filter



jeff

 

[EricBu12]

Now your engine is getting fuel under pressure instead of it trying to pull it.....



See what a Press. guage could do for you?

I have a 3 pod on the pillar and have a boost, pyro, and FP gauge. when you do get the gauge on, I will bet you have hardly any PSI to show like 5 psi at idle. The lift pumps on these are located in a Dumb A** place. (on the side of the engine below the filter)



Electric pumps are pushers, not pullers, so the motor wears out premauturely (sp?) I fixed this problem with a 7# pusher pump. that made too much PSI so I added a regulator after the stock lift pump but before the filter. Also there is a smaller elbow hose from the pump to the filter, toss that and use 3/8" line. run that from the pump to the regulator by way of a "T" then back to the filter. the other end of the regulator can go to your FP gauge.



the return line goes to a filter I have back by the tank, the Pusher is back there as well... The return line goes to a pre-filter that is a 30 miron "rock catcher" to help keep the pumps clean. now with the return from the regulator, even the pusher pump has a small head pressure so it don't work too hard. I now see, with some adjusting of the regulator, 13 idle, and no less than 11- 12 cruise or WOT ... BTW, I have 2 boxes making 331hp at the wheels. Boost is at 29 psi and with that, I have 11 psi fuel..... not bad.

See what I did here

https://www.turbodieselregister.com...d=72391&highlight=My+fuel+system+finally+done

 

[PRout]

Until you verify what your fuel pressure is, it might not be a good thing doing WOT runs.



Not trying to butt in but someone should mention it, because it would be a shame to fry your injection pump due to low supply pressure.



Like they say, the next step here is an fp gauge install to see where you are, and go from there.

 

[krs]

Intelman34,



Shortshift is right and because you said "After about 30 min of letting the truck spit and sputter to get running" I'd say that it's a good bet that the lift pump in your truck is shot/no good/history. The 24valve engines don't need a lot of time to prime after a fuel filter change if the lift pump is good because the first thing that happens when you turn the key to start is the pump primes the system. They're essentially self-priming.

 

[Intelman34]

Im actually just going to get a new Cummins lift pump. Its cheap and it cant hurt to get a new, updated part.

 

[WadePatton]

Originally posted by Intelman34

Im actually just going to get a new Cummins lift pump. Its cheap and it cant hurt to get a new, updated part.

Excellent idea. Mine was on the way out at 50 thousand or so and the replacement is fine now after 30k (knock on wood).



But now I have a gauge and know what it is doing.



Also, while we're on the subject--and while you're in there, you might want to intall some larger banjo bolts, or go all the way and convert to AN fittings. I just did the Wildcat Maximum Flow conversion and have EXCELLENT fuel pressure at WOT with over 400ponies.