Engine/Transmission (1998.5 - 2002) 12v mechanical pump on 24v engine?

[BadDNA]

While hanging out with some of the other northeast guys last weekend we got to pointing out all the oddities on my 98. 5 truck. I've got a 2wd 2 door quad cab with a 24v motor which several people have told me is uncommon, old style fuel filter canister, tappet style ccv (though I think it may have had the TSB performed for this). While we were bs-ing somebody mentioned that some early 24v motors had a lobe on the camshaft for a mechanical fuel pump. If that is the case on my truck, would swapping over to a 12v mechanical pump be a good option for keeping the VP alive? I haven't bothered looking yet to see if there is a lobe on my cam, but if that's as good an option as a FASS or RASP, I bet it would be a lot cheaper in the long run.

 

[Amianthus]

Even if you did have the lobe (which you shouldn't), that lift pump is not going to work for several reasons. One is too much pressure. Another is the pulsing of the fuel supply will raise Cain with the VP. There are several others, but those are the biggies that I can come up with. It just won't be a good idea.

 

[KLockliear]

Actually, the mechanical pump works fine in front of a VP44. We have done a few.

 

[Amianthus]

I tried it once and blew the front seal on the VP. Didn't try it ever again. I suppose it could work with an aftermarket regulator, but still. He doesn't have the lobe on the cam so a cam change would be in order and that seems like a lot of work and extra expense.

 

[BadDNA]

Actually, the mechanical pump works fine in front of a VP44. We have done a few.

So how have you done it? Custom cams or do these few rare 24v cams with the extra lobe actually exist? FP regulator to keep the pressure from spiking?

 

[willyslover]

been running it with a 12 valve lift pump for months now, with a custom bypass for excess fuel... . no more electric lift for me... works great !! BTW I have an aftermarket cam from Piers with the lobe

 

[KLockliear]

So how have you done it? Custom cams or do these few rare 24v cams with the extra lobe actually exist? FP regulator to keep the pressure from spiking?

Yes, we did our white truck back in '02, and have had several customers that have purchased our cams do them too. Our camshaft has the lift pump lobe. No regulator. It would make about 45psi or so at idle. Never had a problem in the 40k miles before we sold it.

 

[Stefan Kondolay]

Get the RASP mechanical pump and be done with it. I have sold over 100 of these units with not even 1 failure.



It comes with a regulator so that you can control the pressure, and set it where ever you want.

 

[HeavyHauler]

BadDNA - how do you have a 98. 5 truck that's a 2-door quad cab? Maybe I'm reading this wrong or something, or maybe you're not including the suicide doors? If so, then the only thing rare about the truck would be that it had the lobe on the cam right?



Oh, and how does 45 PSI to a VP44 keep from absolutely KILLING it? Anything over 14 goes back to the tank right?

 

[BadDNA]

BadDNA - how do you have a 98. 5 truck that's a 2-door quad cab? Maybe I'm reading this wrong or something, or maybe you're not including the suicide doors? If so, then the only thing rare about the truck would be that it had the lobe on the cam right?

Nope, you're not reading wrong, 2 doors, extended cab (quad cab) no rear doors, 24v engine, build date 5/98. I've heard rumors of 24v engines with the fp lobe on the cam but haven't checked mine yet so I don't know if I have one or not, and I haven't talked to anyone who has seen one personally.

Oh, and how does 45 PSI to a VP44 keep from absolutely KILLING it? Anything over 14 goes back to the tank right?

I'd imagine that's the responsibility of the aftermarket regulator, shunt anything over 14 psi back to the tank then let the VP return what it doesn't need as it does in the stock configuration.

 

[HeavyHauler]

Dang, that's the first 98 I've ever heard of that doesn't have the true Quad Cab (4-doors). Technically, it would be called a Club Cab being that it doesn't have the suicide doors.



Pretty weird - anyone else ever seen or heard of one? I wonder if it was a leftover shell from the 97 model year?



That's cool nevertheless - 40 or 50 years down the road it will be a major collectors item. Strange to think about, but true.

 

[BadDNA]

Dang, that's the first 98 I've ever heard of that doesn't have the true Quad Cab (4-doors). Technically, it would be called a Club Cab being that it doesn't have the suicide doors.



Pretty weird - anyone else ever seen or heard of one? I wonder if it was a leftover shell from the 97 model year?



That's cool nevertheless - 40 or 50 years down the road it will be a major collectors item. Strange to think about, but true.

Hrm... collectors item...



So, who wants to buy me a new rig so I can mothball this one, in exchange for a share of the profits in 40-50 years? :-laf

 

[JeffWhite]

a friend came by here awhile back, wanting my opinion on a used truck he

was test driving, it was for sure a 12V, 5 spd 3500 DRW, that I know.

I'm pretty sure it was a '98, and thought it had suicide quad doors...

is that rare? Me, I would have jumped all over it, but didn't say too much,

you know how that is, you tell friend buy it, and then it turns out to be a

turd... He ended up buying a F350 new, drove it for the weekend, and

carried it back. Now he's got a late '04 Cummins/auto, and likes it. The

'98 he was looking at only had about 50K on it, wish I'd have bought it

after my VP started crapping out later. :{

 

[DieselRam30]

Get the RASP mechanical pump and be done with it. I have sold over 100 of these units with not even 1 failure.



It comes with a regulator so that you can control the pressure, and set it where ever you want.

This the absolute best method for eliminating lift pump problems. Have one (see sig) and have rock-solid 15 psi fuel pressure at all times, including WOT.

 

[Fogie]

It's not a Quad Cab... . It's a Club Cab. Both versions were available in 98 and early 99..... around mid 99 the Club Cab model was eliminated. Guess it's not so rare after all. Sorry.

 

[OTRPU]

What's the most economical permanent solution to the lift pump failing problem? I can't spend any more than I absolutly have to. The guys that have the shops offer high cost solutions that I can't afford. I'm in Twin Falls, ID, need a pump solution, and a set of used LT215/85R16 cheap.



Cheers,

Steve J

 

[BRobertson]

There was a RASP failure on one of the locals (Anchorage) trucks.

Bob

 

[Fishin Guide]

I don't know about the RASP, but I do like it. I think it's a great solution to the lift pump issue. I have never run it, so I can't comment on durability, ect, but I think it would be awesome! I was going to run it before I decided to do a cam.



No 24 valves that I am aware of had a lift pump lobe. The guy that said he tried it on his truck and lost the VP insinuated that he had NOT done a cam. I don't know how you can have it both ways.



Anyway, I do have the mechanical setup. It's one of Don M's cams. And I think most if not all of teh aftermarket companies are putting a lobe on thier 24V cams. So, a 12V pump and the 24 vvalve seem to be able to live together. I have some miles on my setup and would not change a thing!!



Dave

 

[rubberneck]

FG, are you running a regulator on the 12v pump, or giving the vp full pressure? I am going to order the cam soon and want to go to the 12v pump also. No more lift pump problems. man that sounds nice.

 

[Fishin Guide]

FG, are you running a regulator on the 12v pump, or giving the vp full pressure? I am going to order the cam soon and want to go to the 12v pump also. No more lift pump problems. man that sounds nice.

Regulator? Nope.



I don't see the huge pressures some of the others guys are getting. I believe Don is using a custom pump now, but I could be wrong.



Dave