92, f250 project

[1970Custom]

Uuuum, that ain't normal...

 

[aussie_f350]

What would cause that? Was run on propane before, had a seperate computer and 8 injectors tapped into the manifold for it. So this is where the problem is in the wiring too I'm guessing. Which sensor tell the front fuel pump that the fuel rail has enough fuel and shuts it off and on?

 

[kiwi f150]

What would cause that? Was run on propane before, had a seperate computer and 8 injectors tapped into the manifold for it. So this is where the problem is in the wiring too I'm guessing. Which sensor tell the front fuel pump that the fuel rail has enough fuel and shuts it off and on?

Two things Andy - there will be a switch over solenoid for changing from gas to petrol (would have turned the petrol injectors off too) - try to trace the wiring from the switch/lpg gauge on the dash back out to that.


Secondly if you still have that computer/manifold and wiring i'd be keen on buying it from you.


.

 

[aussie_f350]

Nah the switch on dash is long gone!! But I have the propane injectors and seperate loom and seperate computer. I will get some pics later and send to you. See if it what you can use!

 

[kiwi f150]

Thanks Andy - still thinking about that changeover switch though .... it would have turned off the fuel pumps as well.

 

[aussie_f350]

Yeah I know!! But I have cut the tape and cover off all of the wiring loom and I can't find it at all, the shop manual I have had diagrams in the back so followed all the pump wiring and it all looks normal!

 

[kiwi f150]

There's an inertia safety switch for the fuel system - in my truck it's on the firewall (dash side) close to where the clutch would be .... maybe on yours since it's rhd it could have been moved behind the kick panel

 

[aussie_f350]

Yeah mate, been over it!! Thanks

 

[kiwi f150]

Ok, we just did 7 hours of checking and double checking, found to ground wires to nothing, one was on a plug at rear of truck that I'm not sure what goes to, one on the passenger(your driver) side headlight. We now have firing injectors when a noid light hooked up but very weak, hardly any fuel. But still no fuel pumps unless powered from another source. Can't get power to the brown wire on the fuel pump relay but power to the other 3?
So anyway, we just jumped the fuel pumps and cranked it, will run on starter spray and fuel in throttle body but not on its own. Pulled injectors again and noticed this

Is it me or is that all melted?

Been having a look online Andy and found this page for you http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/fuel-pump-relay-tests-1

Sounds like you have either a dud relay or the computer isn't supplying a ground to the relay to turn it on plus if you have the three pump fuel system (it should be like mine has) it sounds like the low pressure tank pumps are wotking but the frame mounted high pressure pump is d**ked - looking at the pics from the prang it had i wouldn't be surprised if it didn't get a shake up .... have you got a fuel pressure gauge Andy.
Maybe get someone to put their hand on the high pressure pump (inside left chassis rail under footwell) and see if its even running at all when you jup the fuel pump relay.

 

[aussie_f350]

Yeah mate both the tank pump and the rail pump are working, the fuel rail is full of fuel!! Got heaps of spark! I cranked it with injector out and hardly any fuel comes out of the injector but I'm not sure how much is supposed to come out

 

[aussie_f350]

That's when we jump the pumps!!

 

[kiwi f150]

I've never tried an injector like that Andy so i'm not sure either ..... wouldn't think it would be a great amount though.
Looking at the pic of the injector it's got hot and could easily be gummed up inside too.
Have you got another set of injectors you can try ..... i know its a pain in the proverbial to change the right bank but at least you'd eliminate that problem.

 

[1970Custom]

Here Andy.... This should give you a comparison....

 

[aussie_f350]

No where near that much comes out of them!!! Only just a little slight spray, hardly any!!!
But could that be because they aren't getting full amount of power? I looked on eBay last night I can get full set of reman for less than $200 so they are on there way!!

 

[kiwi f150]

Have you got a mate with a fuel pressure gauge Andy? - you'll know for sure then ..... it isn't me saying this but if you hop under the truck and pull the outlet line off the frame pump then see how much pressure you have there - does it take a bit of force to stop the flow or is it pretty slack?

 

[aussie_f350]

Heaps of force mate, the little bleed screw on the rail on the last injector has heaps too!!

 

[kiwi f150]

Oh well that makes it an injector issue then - injectors blocked or the pulse length from the ecu is out..... is the earth side of the injection wiring loom all ok?

 

[aussie_f350]

Yeah checked all the grounds yesterday, anybody have any experience with noid lights? I got them to light up but not very bright?

 

[dustybumpers]

I did not realize you had the 3 pump system.
There is a fuel pressure transfer delivery module In the system that goes bad on that system.
It is the part where all 4 lines from the tanks go in one side, come out as 2 lines from the other side. Down by the rail fuel pump and filter.

It's purpose is to return the fuel to the tank it is coming from, but when it becomes bad, it clogs up, and limits fuel pressure, and eventually cuts it off.
I have replaced this unit twice on my 89, and once on my 87

Remove the fuel line from it to the rail pump, and see if the in tank pump is pushing fuel through it.

 

[aussie_f350]

We have heaps of fuel in the rail when the pump is wired to run from another source