Engine/Transmission (1998.5 - 2002) No 2 second prime

[Popiol]

Turn key on, does not activate the two second prime, fuel pressure does not raise. Start truck and fuel pressure raises, truck runs fine. Why isn't the two second prime activating? Installed new lift pump still same problem. Any ideas?

 

[Joe G.]

You need to put your post on one of the engine/transmission forums depending on which year your trick is. This forum is for discussion of web site stuff.



It would be a good idea to fill out your signature so people you can help you know what year and model you are driving.



Welcome to the TDR.

 

[ToolManTimTaylor]

Here I'll move it for ya

 

[Billy Diesel]

Turn key on, does not activate the two second prime, fuel pressure does not raise. Start truck and fuel pressure raises, truck runs fine. Why isn't the two second prime activating? Installed new lift pump still same problem. Any ideas?

When you say "Turn key on," are you also bumping the starter, or are you just turning the key to the "on" position? Assuming you have a 24V, if you just bump the starter without actually starting the vehicle the LP will run for approximately 10 seconds.

 

[Popiol]

Turning key to ON not bumping. It would build up F. P. before for 2 sec. when I would turn key on.

 

[Billy Diesel]

Turning key to ON not bumping. It would build up F. P. before for 2 sec. when I would turn key on.

That's interesting. On my '02 just turning the key to the on position will not cause the LP to run. Hopefully someone with a '98. 5 can chime in with their experiences.

 

[tractorface]

Mine runs the fuel pump for a couple seconds when I turn it to on (wait to start light mode) Than goes off until I crank it over. I am pretty sure this is how they all work. I have noticed on occasion if I just went wait to start than turn off without cranking the next time I go to Wait to start I get no fuel pump. Just figured this was normal. Huh?

 

[ntillm01]

My 01 used to "prime" the fuel pump for two seconds when the key was turned to ON (not start-bumped). That was with the original ECM flash software.

I had the dealer reflash to the latest to get the cold/fast/3cylinder idle function. After that, I can hear the pump run about 1/2 sec when the key is turned on. I haven't tried the bump-start fuel pump run function since then, but I assume it's still there.

I think the newer flash software versions shortened (eliminated) the two-second prime. I didn't notice any difference in crank-to-start time or running issues. I don't think it is that critical to have the fuel pump prime in this fuel system. It's typically a gasser fuel injection thing so the fuel injectors have pressure before cranking. Our fuel injection pressure happens while it's cranking.



My 0. 02

 

[Marco]

The latest softwares do not run the lift pump for a couple seconds like the older SW's did! No matter what MY the truck is.



Bumping the engine still does the 15 (?) second thing.



Marco

 

[tractorface]

Why

Did they disable that for a reason?

 

[Marco]

Did they disable that for a reason?

Yup, hard start caused by high fuel pressure...



Marco

P. S. Maybe also more wear for the lift pump to run against the VP?

 

[Popiol]

Now No Wait To Start Light. Also The Only Way The Two Sec. Prime Works Is By Removing The 20 Amp Eng. Fuse And Reinstalling It. It Only Works On Time.