7.3 no start

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Oct 14, 2023 | 09:36 AM

SWE_lollo03

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7.3 no start

I have a f350 from 88. I swaped the injection pump like 2 weeks ago and drove it for a couple of hours. Next day it was really hard to start and i noticed some leaks between some lines and injectors so i fixed that and got it runing again. Didn't drive it for a couple of days then coulden't get it runing again after, turns out i had some leaks between the injection pump and the lines too so fixed that but now it wont start anymore. I have fuel to the injectors and the glow plugs are brand new and working. Anybody know what could be wrong?

Oct 14, 2023 | 02:12 PM

Prototypemech

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From: Mojave, Ca

Im guessing those leaking fuel lines caused all the fuel to run back to your fuel tank and all your fuel lines are dry. As the vehicle ages, the mechanical lift pump has a harder and harder time trying to suck fuel up to the tank if the lines are dry.
You can remove your fuel filter and fill it with diesel fuel if it's dry. That might let the engine run long enough to reprime your dry fuel lines.

Oct 16, 2023 | 06:46 AM

freightdogfred

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Joined: Nov 2004

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From: St Thomas

The cam lobe driving the lift pump wears on an older IDI, it’s just the way it is. The lift pump has a hard time picking back up a prime, and if your fuel system isn’t super-tight (absolutely no leaks, supply or return) the pressure bleeds down and it’s hard to start. After changing a lift pump, bending the arm on the pump to give it more “lift”, removing it/lines 2/3 times to prime the system, I gave up. I bought an electric Facet pump https://www.pegasusautoracing.com/pr...asp?RecID=9671 and wired it in with the FSS (fuel shutoff solenoid) so it energizes when you turn the key on, and shuts off when the key is shutoff. I wired it to 10A relay i got from a dismantler, thru an inline fuse, right to the battery. Now, the truck sits for 2-3 months (its a dump truck) and after cranking once or twice for 10 seconds, she fires right up. If I use it daily, she starts immediately, no delay.

Oct 16, 2023 | 07:11 AM

Prototypemech

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From: Mojave, Ca

Many idi owners abandon the mechanical pump for an electric pump, but I promote keeping the original mechanical lift pump. It cheap and reliable. Less complexity=less problems. Ford and international believed the lift pump was a solid solution all the way up to the super-duty body style.
The secret is to get a ford or international OEM new mechanical fuel pump and not a cheap AutoZone brand pump. The fuel system needs to be completely tight. You should not smell diesel fuel when you pop your hood.

Oct 16, 2023 | 07:36 AM

freightdogfred

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Joined: Nov 2004

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From: St Thomas

Quote:

Originally Posted by Prototypemech

And therein lies the rub, keeping the fuel system tight. Especially an older IDI. Especially one with a two tank system (like mine) that also uses an electronic fuel selector valve, 6 port, that Ford no longer even sells. So going OEM is no longer an option, and one day that OEM lift pump, driven by an old worn out cam is going to leave you high and dry. Trust me, I wanted to leave it stock but I didn’t have time to roll around in the dirt fooling with it. Ford’s penchant for using the cheapest bullshat they could to maximize corporate profits has bitten them in the ***, I for one would never, ever buy a new Ford. Have you had to drop your tank(s) yet, to change the cheap-azzed plastic fuel strainers the literally disintegrate in the tank? You’ll know yours are gone when the engine quits with the tank still 1/3 full. Here’s the video to show how to do it when you finally give up. I mounted mine next to the Chinese fuel selector valve (cause Ford don’t sell em) on the frame rails but perhaps it will help you.

BTW, I’m also an A&P.

Oct 16, 2023 | 09:04 AM

Olds64

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From: Edmond, OK

Quote:

Originally Posted by Prototypemech

The secret is to get a ford or international OEM new mechanical fuel pump and not a cheap AutoZone brand pump.

^^^THIS^^^

Especially if you're going to stick with a mechanical lift pump. I bought a parts store cheapie mechanical fuel pump and the diaphragm ruptured. It started pumping diesel into the crankcase. Luckily I was keeping an eye on the oil level and I caught it before a bearing went bad.

If you decide to go with an electric fuel pump definitely go with a Facet Duralift from the linked supplier.