EFI Start Issue need help

[DEEPWOODS]

When I try to start it ,it turns over and will not start like the fuel injection pump times out . If I try again it starts up instantly or if I try to start it and turn it off as soon as it turned over and try to start again it starts instantly. Any ideas what's going on or any help? Thanks Keith

 

[AZ69EB]

Pull codes. This should pint you in the right direction.

 

[DEEPWOODS]

Engine light is off and no codes

 

[AZ69EB]

Verify fuel pressures when starting and running.

 

[pcf_mark]

Yes check fuel pressure before you start. As a test turn the key on do not start wait 3 seconds. Repeat this three times. Then start it. If it starts right up your pressure is is dropping to zero in the rail when sitting. When you go tot start it take 4-6 seconds to get fuel up there.

My regulator must leak mine goes to zero psi after shut off. Three key trick works everytime. Also makes them cranky when starting hot.

 

[EFI Guy]

Yes check fuel pressure before you start. As a test turn the key on do not start wait 3 seconds. Repeat this three times. Then start it. If it starts right up your pressure is is dropping to zero in the rail when sitting. When you go tot start it take 4-6 seconds to get fuel up there.

^What he said.

 

[DEEPWOODS]

I turned key to on 3 times stays 0 lbs. every time. When I go to start it go to 36 lbs. wile running cut it off instantly goes to 0 lbs . So what should it do? Also I thought the pressure should be more like 50-60 Lbs ? Is this a bad or weak pump?

 

[BoulderMike22]

Couple things:

Did you wire you're fuel pump to hot on start or run?

If it immediately drops, you do not have adequate pressure. You could replace the fuel pressure regulator. Is it a return or returnless fuel rail?


Sent from my iPhone using Tapatalk

 

[DirtDonk]

Which EFI are you running? Ford or aftermarket?
This won't necessarily tell us anything about what's going on specifically, but gives you the pressure readings you're looking for.
While that 36 is just adequate for running a earlier Ford EFI (EEC-IV?), it's beneath the lower level of normal which is around 40-49 if I remember.
If you're running later Explorer (EEC-V?) then yes, it's more like 55-60 or something like that. But the others will know that, so don't go by my memory.
Some aftermarket TBI units use still more. So even if you were running a steady 36 it would be below par. Since it's not even consistently pressurizing though, you obviously have something wrong with either the fuel system or whatever is controlling it.

Sounds almost like a bad wire or connection to the pump. But I suppose it could be a bad pump on it's way out too.
What pump, where is it located, and how long has it been in service?
Single pump, or a low-high setup?

Johnny-5 needs more input...

Paul

 

[DEEPWOODS]

Ford 5.0. I think it's eec-v but not sure how canI tell ? It has Ryan's harness there is a return line and a pressure regulator on the rail. There are 2 fuel pumps one next to the tank and one one on the passenger frame rail.

 

[DEEPWOODS]

Also I can hear the pump for 2 or 3 seconds then it stops if I don't go go on and start it

 

[Timmy390]

Turn key on, you should hear the fuel pump cycle for a second or two. so that's normal.

You need to verify the pump had power in key position "start".

Try this......put the rig in neutral

Turn the key to the "on" position the off letting the fuel pump cycle 3 times.....on the third time, leave the key in the "on" position. Jump the starter at the solenoid on the finder.

If it stats then you know the fuel pump is not wired correctly to have power with key in the "start" position.

I power all my relays off the Green with Red stripe wire at my ignition switch which is hot in both start and run.

Tim

 

[DEEPWOODS]

I changed the pressure regulator today it was not the problem still doing the same thing.When I cut it off it goes to 0 pressure instantly .Do the fuel pumps have a check valve?

 

[Skiddy]

I am confused, are you saying when you turn the key off is when the pump stops and pressure goes to zero

 

[DEEPWOODS]

Yes you can cycle the pump 3 or 4 times and it will not build any pressure. After it is running and you cut it off it goes to 0 pressure instantly.

 

[ransil]

make sure both pumps are working at the same time.

 

[DEEPWOODS]

Both pumps run about 2 seconds key on if you don't go to start . I can't hear them when the starter is spinning . I will pull a wire up from positive and check that they are still running when I go to start today . I have found that if you go to on then instantly turn off then go to on- start it will crank right up but it is getting where even if I do this It might take more tries. Could I have a injector stuck open is why It wont build any pressure? Would this send a code? When it runs it is great no skip just this hard starting issue

 

[dbasile]

I had a similar issue. Try to run a jumper line to your pumps directly giving them power you should start. If it does double, triple check your grounds. If they are good check your fuel pump relay. If those are all good the check each of the harness injector plugs with a diode light. If those check out, check your injectors. By using a long screw driver (blade placed on injector other end held near ear) or stethoscope, you can hear if the injector is opening and closing. It should be a consistent open and closing sound, kind like a tapping when turning the engine over. If all of that checks out, it is probably your computer. Did you buy a new computer or is it a junk yard computer? A bad computer will not throw codes. IF you have a friend with a running 5.0 borrow their computer for a minute and try starting your truck. Hope that mat help alittle

 

[BRONCO26]

The prob u got isn't going to give you a code you have a wiring issue or relay issue if you want call me at the shop tomorrow and I will look at a wiring diagram and help you.

 

[EFI Guy]

It sounds like you have power to the pumps, but it would be best to confirm that with a helper and a test light.

I talked to someone recently that had a similar problem. The pump he was using had some sort of check ball in it that only worked when the pump was mounted vertically like it was in the tank. When the pump was mounted horizontally it would bleed pressure instantly. It might not be your problem but it would be a fairly easy thing to test.