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91 7.3 will not start

little history on the truck just changed the batteries 2 weeks ago ran fine last Sunday it sat for a week and went to start it today. It started ran wrought then quit. it will only start if I let it set for a couple of minutes then as I crank it I pump the hell out of it then it starts runs wrought then quiets. I checked the glow plug they checked out good and its 80deg out. I changed fuel tanks thinking it was the pump. no help I'm going to change the fuel filter next week. and try it again. with the key on I get a good stream of fuel out the shradder valve.

Any insite would be helpful.
how do you check the injector pump?

thanks
chris
 
Last edited:

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
When you change the fuel filter make sure you fill it with clean fuel before reinstalling. We had somthing similar in the shop couple weeks ago it was the low pressure pump.
 
Up date and question?
Cracked the fuel line coming from the manual fuel pump to the filter and cranked it, got fuel. Cracked the line from filter to injector pump on both ends and cranked it, got fuel. cracked line from injector pump to injector and got nothing! so I guess its the injector pump? were is the best/ cheapest place to get an injector pump?
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
Before buying a pump you want to make sure you have power to the 2 solonoids on the pump one is the advance and the other turns the fuel on and off. If I remember correctly they are single wire with a white/clear connector at the pump.
 

Fellro

Moderator
Staff member
Also, if it lost it's prime, you will have to bleed out all the injector lines to get it to clear out. All it takes is to get an air lock on the filter, and the IP will not be able to pump fuel, and then you have to bleed them all out. Diesela are sensitive that way. The injectors open by hydraulic pressure, so if there is air in the lines, then there is no injector opening...
 

Fellro

Moderator
Staff member
That is about it... be sure not to crank too long a time for risking killing your starter. Crank for a reasonable amount of time (30 seconds or less),then let it sit for a few minutes.
 

Fellro

Moderator
Staff member
The fuel pressure should be around 7 psi or so, not overly high. The return lines need to be able to handle diesel, and tend to be pretty small. You can get new hose, caps and o-rings on ebay for around $20-30, search for return line kits.
 

flareside_thunder

Florida Chapter member
7,812
246
sounds like it's got air or the mechanical pump took a crap and is not keeping prime...worked on this same issue tonight...turned out to be air getting in at the fuel heater plug....seems like you're getting air but try running a wrie from your positive terminal to the positive on the fuel pump solenoid.
 

Fellro

Moderator
Staff member
To clarify, I believe you mean injector pump solenoid... I run an electric fuel pump, but it is not factory of course. It sure is nice not having to crank to prime filters and such...
 

Fellro

Moderator
Staff member
I have encountered problems from time to time when the IP seems to lose power. My old man's 84 did this a few times, and my 86 pulled it when my sister was out east. I had her hotwire the IP, and it fired up. She then pluged it back to the normal wire, and it has been fine since... I had to hotwire the old man's a few times.
 

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