Mechanical fuel pump - 7.3 IDI

[yellaheep]

Talk about frustration...........

In trying to shake down my high RPM fuel delivery issues, I decided to go ahead and replace the mechanical fuel pump. It appeared to be the factory original as it still had the International grey paint all over it.....

Well I removed the damn thing and called my local NAPA. The one they had has a very different looking pump lever than the one my truck had. The NAPA one was about 3/4" longer and just some mild bends - almost a straight upward lever. The orig. unit I removed has quite a significant pair of bends making it look like an "S" in a sense.

The first NAPA pulled up their photo of the pump and by part number, it showed the pump should look exactly like my original one... they said the pump in their box was mis-packaged so they called two other stores - they described the lever and both said "Yeah, ours has the sharper "S" bends in the lever............. I get to those stores and it's the same damn one as the first.

Advance Auto showed two on their computers - one was the wrong lever and the other was a Bosch unit with the correct lever, but they can no longer get it.

I stooped to go to Checker Auto and they too only had the longer, straighter lever pump.

Did Ford do a re-design of the fuel pump? Could the straight lever be correct? To me, looking at the pumps side-by-side, I don't see how the cam lobe would correctly contact the straight lever pumps......

I'm pretty unhappy....... and I have a busted, immobile truck in my driveway........ at least until I put the old pump back on and figure out how to find it's replacement.

Also, am I going to have problems with air in the lines since it'll be sitting with out being connected to a pump for a day or two?

As always, thanks in advance!

 

[93turbo_animal]

I just used the napa pump no problem here

 

[yellaheep]

Did you notice a difference in the shape of the levers? Was the old one different from the NAPA one? Or did your old one match the NAPA one?

 

[Diesel JD]

There is a significant change, I can't remember all the details. I do know that a blockoff plate and an electric pump MIGHT be easier than having to screw around with that mechanical fuel pump. They are no fun to mess with. The flips ide is they don't usually fail. If you get the new mech. unit just make sure it rides the cam appropriately. I think that may be the reason for the redesign. One style of pump would do serious engine damage if it were at all misaligned with the cam. Good luck,
JD

 

[h2odrx]

Sounds like a good time for a RED!!

 

[yellaheep]

Well, you guys are kinda confirming my thoughts.........

In looking at the design of the old pump lever, it seemed that the cam would press into it rather than just move it up and down.

The pumps NAPA had looked more like the bottom stroke of the cam lobe would press straight down on the lever.

If anyone can confirm the design change, that'd be a huge relief, but I suppose that since so many different parts houses had that same new pump, that would lend toward there being a design change somewhere along the lines.

BTW, here's a couple pics of the rig I'm trying to fix...... Just put those tires/wheels on it the other day, sure made a big difference in looks over the grey steelies........

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For those that noticed, the damage to the driver's rocker was from that wheel coming off and the headaches I had trying to source those pesky auto-hub clips..... my first posts here and the whole reason I initially came to Oilburners.

 

[icanfixall]

Nice looking rig. The mechanical pumps were redisigned because many installed them on top of the cam excentric and ruined them and the cam. So go ahaed in make sure you install the arm below the cam excentric and all will be fine.... Till you install the Holley Red electric pump. Its really the better idea on fuel delievery.

 

[Diesel JD]

Good call Gary. I was trying to remember what that was all about. Remember how on the other site, any time someone would replace one, Pete would come out with his TSB on how to properly install a mech pump for that reason. I sure don't miss that thing! I love my Holley Red.

 

[Mr_Roboto]

Mine had a slip of paper inside that explained that the pump lever was redesigned and a direct replacement for OEM.....

I don't think International designed their pump, I think the afermarket made a "will fit" design that was cheaper.

 

[93turbo_animal]

yeah sorry it was the different design I put back in just make sure the arm is below the cam and all is good

 

[reklund]

Man, that's a good lookin' truck! But I'm partial to that color combination... Don't see too many on the road, much less diesels. There's one or two in town, but they're gassers.

As for the fuel pump, have you talked to the guys at Ford or International? I avoid the aftermarket junk at all costs on my truck- it never seems quite right.

Ryan

 

[yellaheep]

Thanks guys, that's exactly what I wanted to hear. The re-design, cam lobe thing makes perfect sense.

Since I'm just fixing and flipping this truck, I'll stick to the cheap fix for now and get a solid NAPA pump and get it running again. If I were keeping it, I'd consider the electric pump fix.

Thanks again guys - as usual, you all were a HUGE help!

Would you believe I bought that truck for $700? Seemed cheap enough...... I've got about $1400 in it now.

 

[yellaheep]

Ok, pump's in, but I can't get fuel to the injectors. I have fuel up to and in the fuel filter...... but all it'll do is crank continuously, no fire.

I'm pretty certain that the pump lever went in correctly, I could actually feel when the arm went up over the cam lobe, and when it was under the lobe - the pump was also angled upwards until the bolts were tightened down which suggests to me that the arm was under the lobe and keeping it from sitting flush.

Any suggestions?


EDIT: Heh heh..... guess I was a little impatient...... about 2 minutes more of short crank overs and it fired right up. Seems to have a bit more high RPM power when driving too....Wonderful! Now I need to get some fresh fuel in it and I'm optimistic that it'll run the way it should!

 

[93turbo_animal]

well thats good to hear but I'm curious why you think the lift pump was the cause off the high RPM power loss? Did the fuel filter light come on during high RPM's? cause if it didn't and its working corectly you had plenty of fuel at the IP. More then likely low power in the high RPMs is a weak IP and/or needs timed

 

[yellaheep]

Ok, took it to get some fresh fuel today and drove it about 30 miles. Seems to be an improvement again having added the fresh fuel. (And I'm kinda jealous of the nice ride quality compared to my Cummins 3500.....)

One thing I noticed while driving up an on-ramp to the highway..... under an acceleration load, climbing the ramp, I saw the exhaust puff out an occasional burst of black/gray smoke thicker than what steadily coming out.... like a misfire, but I didn't notice any change in the engine performance.

The truck still does seem like it's got some fuel delivery issues, almost more like some fine tuning maybe.

The grey smoke that was constantly coming from the exhaust under load is gone now. Just a bit for the first few minutes on cold start up, but after that, not much noticible smoke at idle. On normal acceleration, the black smoke seems reasonable, and under heavy pedal, it blows a pretty good black flow until the truck is moving, then it lightens up.

I've got the tach sensor waiting for me to pick up tomorrow - once that's in, I'll have a better idea of how the engine is performing.

Trying to gauge it's performance when my daily driver is an '04 Cummins 3500 is pretty tough. This old Ford seems to certainly have the torque, but it won't win any drag races.......

If the IP is going bad, would it still have a really smooth idle? It idles great, initial throttle up is good..... just seems like there's still a bit of sputtering at the high RPM range. The IP clatters more at high RPM, and having added the new mech. fuel pump, some of that clatter seems to have eased up - I was thinking that if the mech. fuel pump was having problems supplying the IP with fuel, the IP would certainly make more noise.....maybe?

Thanks again guys for all the great info and support! I'll take any additonal ideas you have to continue to work the bugs out.