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Flat cam lobe for fuel pump?

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RenoHuskerDu

Flat cam lobe for fuel pump?

Got a head scratcher with Puddles the 1986 Bullnose 420 IDI. He died on my wife the other day (loss of points, but not a hemorrhage) nearby on a quiet road. I was there within 15 towing the car hauler (most points recovered). One of our sons also heard us on the HT and showed up.

Puddles had just been thru a fuel tank repair where the inlet was brazed back into place. I wondered if muck from that op or the time it was cracked open had plugged the fuel filter. We pulled it and garsh, it sure looks clean.

Tried a new filter anyway, no better. Then we cranked with the fuel filter off, into a jar, and got very little diesel. Hmmm, fuel pump? It was new a couple months ago. NAPA said "sometimes that happens" so we put in a known good used pump.

Still no start, no fuel delivery. We took the inlet line off the fuel pump and put it in a jar of diesel. Cranked for 5 seconds or so, and no fuel got sucked in the pump. So the pump isn't pumping.

I wonder if the cam lobe that powers the fuel pump might be flat? I've heard of that in the past.

Reno in Central Texas, 86 F250 XLT Lariat eclb 2wd 6.9, plus 2 Bricknoses, 1 Aeronose that's getting a Bullnose front clip, and parts trucks. Busy lads, father and sons wrenchers.

RenoHuskerDu

Re: Flat cam lobe for fuel pump?

My next question will probably be

Which electric fuel pump do y'all recommend?

Reno in Central Texas, 86 F250 XLT Lariat eclb 2wd 6.9, plus 2 Bricknoses, 1 Aeronose that's getting a Bullnose front clip, and parts trucks. Busy lads, father and sons wrenchers.

Gary Lewis

Re: Flat cam lobe for fuel pump?

Administrator

You are asking questions I can't answer. I don't know how a fuel pump for an IDI works, so don't know if there even is a cam lobe. But, if there is I'd think it could go flat. On the other hand, what drives that cam?

As for what electric pump, I have no idea what pressure an IDI needs at that point. Do you?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: Flat cam lobe for fuel pump?

Administrator

In reply to this post by RenoHuskerDu

I've never seen a cam gear eccentric go flat.
I have seen the arm snap, or the pivot go out.

I'm going to guess if you pulled it out of the truck you would have seen either of the above.
But there's not a chance you're pumping that thing 4-5 x a second like it would in the truck at idle.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

RenoHuskerDu

Re: Flat cam lobe for fuel pump?

In reply to this post by Gary Lewis

The IDIs use an old-school diaphragm fuel pump on the side of the engine block. It's driven by the camshaft that also operates the valve train. Fuel pressure is somewhere around 10psi and not critical. This is all just like a Chevy or Ford V8 that you remember from the 50s-80s.

Scanning this article, now I wonder if we messed up the pump by not checking the mentioned cam lobe's position.
https://www.dieselhub.com/maintenance/6.9-7.3-idi-diesel-fuel-pump-replacement.html

Reno in Central Texas, 86 F250 XLT Lariat eclb 2wd 6.9, plus 2 Bricknoses, 1 Aeronose that's getting a Bullnose front clip, and parts trucks. Busy lads, father and sons wrenchers.

Gary Lewis

Re: Flat cam lobe for fuel pump?

Administrator

Interesting. Yes, I remember the problems of getting the tip under the cam. The pump did not work.

So that could be the issue. The original pump died and the replacement's arm went above the cam.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Flat cam lobe for fuel pump?

Administrator

In reply to this post by RenoHuskerDu

If it was 'months ago' the truck never would have ran with the arm on the wrong side of the lobe.

These are just like gasoline truck mechanical fuel pumps, and will leak into the crankcase if they fail.
(Well, aside from being low, on the passenger side)

Pegasus has the Facet electric lift pump, but then you need to splice the lines and fit a blanking plate.
If the original pump lasted 30 years why not just replace it?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Flat cam lobe for fuel pump?

Administrator

Jim - You are right. I thought he'd said he put a new pump on and it wouldn't pump either, and I was thinking the first pump died and the second pump got put on incorrectly. But that's not what he said.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Flat cam lobe for fuel pump?

Administrator

In reply to this post by RenoHuskerDu

RenoHuskerDu wrote

Hmmm, fuel pump? It was new a couple months ago. NAPA said "sometimes that happens" so we put in a known good used pump.

No Gary, you're right!
One died and another doesn't work.

So, perhaps the "known good" one mistakenly got installed wrong.
I know these are in a tough spot and I usually just cut the fender liner back after removing the passenger wheel.
But it is still akward.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Flat cam lobe for fuel pump?

Administrator

Yes! That's what I was thinking - the known-good one missed the cam.

Gary, AKA "Gary fellow": Profile

RenoHuskerDu

Re: Flat cam lobe for fuel pump?

Thanks guys,

I grilled my son who installed it and he's sure he had the arm under the cam lobe. He could feel having to push up on the lobe, down on the arm, to get the pump seated on the block.

We're trying a Facet. Pegasus has a great price on them, better than fleabay or Bezoszon. Any suggestions on where to get a blockoff plate?

https://www.pegasusautoracing.com/advcat.asp?CategoryID=FUELPUMPS

Reno in Central Texas, 86 F250 XLT Lariat eclb 2wd 6.9, plus 2 Bricknoses, 1 Aeronose that's getting a Bullnose front clip, and parts trucks. Busy lads, father and sons wrenchers.

ArdWrknTrk

Re: Flat cam lobe for fuel pump?

Administrator

This post was updated on .

I use Pegasus for braided lines and fittings.
They make them up fast and don't ask questions about street use.

I'm not sure how the diesel pump compares with my 460 fuel pump or Windsor mechanical pumps, but if the bolt spread is the same, blanking plates are common.
Hot Fuel 460's and all the early EFI trucks used this cover plate on the timing case.
NAPA has one for $10 w/o gasket https://www.napaonline.com/en/p/BK_7354369?cid=paidsearch_shopping_dcoe_google&campaign=GSC-Fuel-Emissions&campaign_id=10951730297&adgroup_id=113117085528&adtype=pla&gclid=CjwKCAiAkJKCBhAyEiwAKQBCknfSytNkJ8IwMB_oNVYyQ64fJrHyYceH7AMv8sidz_0NaxLasoeJGRoCCZIQAvD_BwE&

I don't have a way to view my parts CD, but if you end up at NAPA you might compare your dead pump flange to a pump for a gas truck.
If it is the same, then the plate should work.
(Note! 335 series 351M, 400 have a fuel pump with top and bottom bolts. These are definitely not what you want)

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.