Engine/Transmission (1998.5 - 2002) How long does your lift pump run?

[jelvington]

I have had my truck since Dec. of '01 and every time I turn the key and wait to start I can hear my lift pump run for a few seconds. Friday I took my truck to the dealer to have the fuel pressure checked because I felt I was loosing power on acceleration.

They checked it ok at 15psi bump, 14psi idle and 10psi wide open. They flashed the module (tsb 18-24-99) and said the lift pump is fine. Since I left there when I turn the key to wait to start, the pump stops almost as quick as it starts. Is this normal? The truck does run fine, its just that the pump doesn't run as long as it did before taking it to them.

 

[jwgary]

Mine used to run for about 15-20 seconds if you bumped the starter. It stopped doing that on Thursday and I just got a call this morning that my truck is finally fixed. It is a real bummer that these things go out so quickly. I started having problems with it right around 50k miles. I don't know if they did any ECM flash or not. I guess I will find out later today when I get the truck back.

 

[WyoJim]

jelvington... I think the reflash may have brought it up to date.

My fuel pressure gauge swings to 15 lbs then doesn't even hesitate, just drops right back to zero when I turn the key on to start. Can't take over a second or two. I consider this normal.

A fuel pressure gauge would be a good investment for you. And I think there is a lot of hype connected to the lift pump problem. An FP gauge would help you sort the hype out from a real problem.

 

[otis]

My 2001 lift pump ran for two to three seconds (which died at 60k) and my new 2002 runs for only half a second after turning the key.

 

[jkern]

i believe that it runs as long as it needs to to build up a pre-determined amount of pressure before it shuts off. my stock pump would run about 4 seconds, my new pumps only run about 1-2 seconds.



jeremy

 

[jelvington]

I was thinking it probably has something to do with the reflash as WyoJim said. From what I've read here it doesn't seem like anything to be concerned with. Thanks for the input guys.

 

[mikel]

The pump on my '01 will run about 1/2 to 1 second when the key is first turned on, it's done this from day one. If I bump the engine it will run about 20-30 seconds.



I had a '99 that would run about 8-10 seconds when the key was turned on.

 

[AggieJustin]

My lift pump runs for about a second, just long enough to sweep my fuel pressure gauge all the way over to 15. My old lift pump did about the same. I have noticed a couple of times that it did not run when I turned on the key, but it keeps good pressure once I'm started..... hoping that this pump isn't thinking about retiring anytime soon.



JM

 

[A Johnson]

Jelvington, your lift pump doesn't run as long due to the reflash. This was to help aleviate hard starting problems. The model year or lift pump part number makes no difference, it all depends on the software revision number installed in the ECM. All sounds normal to me as long as you have good pressure with the engine running. --- AJJ

 

[WadePatton]

TSB 18-24-99

-intermittent stumble-



I had this reflash done yesterday, and suspected that maybe other things might be in the new software. Sure enough, one thing that I can observe, the LP cycles very quickly now on Key On. It used to swing all the way to 15psi now it only does 3psi.



I've never had a hard start, but waited until the pressure dropped after reading about high-pressure hard starting. So I'm glad for that change. It should also prolong the pump life just a wee tad. Especially since the windows don't work in the ACC position(!) meaning we have to cycle the LP any time we want to move the windows with the engine off.



Wonder what else the upgrade might have changed?

 

[jerrethomas]

i noticed the same thing after they flashed the ecm for the engine stumble tsb. seems to run ok though

 

[tazzen]

wade



just buy a turbo life saver timer. it has a kill switch. turn the switch off. turn key on and no lp cycle. i know lot of $$$ to make the windows work right.