F150 wont start???

[tuekwik]

I bought 1991 F150 4WD , 351, the truck sat for over a year. I got fuel going to the fuel injectors, I also have a spark but the truck won't start. Had the battery tested and it was good. Tried cranking it over a couple times then removed two of the spark plugs and they were dry. I'm stumped!:confused: Any ideas? Thanks.

[sickrick]

I know that you have fuel going to the injectors but do you have a good supply? remove the shcrader valve from the fuel rail and using a piece of rubber tubing see if fuel continues to flow while cranking the engine . If it does not flow try swapping the fuel pump relay for the horn relay.

Also a single injector on that truck can be shorted and will not let the others function, disconect them one at a time and continue trying to start the truck.

Opps, first things first go get 5 gallons of gas, no matter what the gauge says.

Did you hear it run prior to buying it or did the person you bought it from tell you it ran when parked?

[tuekwik]

Where would the Schrader valve, fuel pump relay, and horn relay be located? I poured about 7 gallons. The truck was my friends and he parked it because his transfer went out. Thanks for your help.:D

[sickrick]

Lets start with the relays, they are located in a plastic box on the drivers side fender. thet cover snaps off and you will find the relays inside. they are labeled on the bottom side of the cover I think.

The schrader valve is on the fuel rail (the thing the injectors go into) it is under a little red or black plastic cap about the size of the cap on a tube of toothpaste. Inside that cap is a innercore like on a innertube, when you remove this and crank the engine you should get a nice gas shower!

If you have a helper with you have him get down by the fuel tank and put his ear up to it and listen for the sound of the fuel pump turning on when you turn the key from the off to the run position. I believe that the pump is in the tank in that year of pickup but there is a small chance it is on the framerail by the fuel filter. If it is on the frame rail check for clean connections.

Hope this helps.

[tuekwik]

The shrader valve has fuel going thru, I pushed it down and almost got sprayed, a lot of pressure. I checked the relays, all good. I can hear the fuel pump kicking on.

[ChuckH]

Have your injectors professionally cleaned, then go from there.

[tuekwik]

How about the fuel pressure regulator? Does this 1991 have, where would it be and is that a possibility? Thanks.

[sickrick]

In my experience the regulators a not normally the suspect component.
Start unplugging the injectors one at a time and try to start it. only have one injector unplugged at a time.

Also even if you got sprayed that does not mean it is getting good pressure and volume (it probable is), to make certain remove the valve core and use a piece of tubing to spray the fuel into a container while a friend cranks the motor. By the way that system runs best at around 27 psi I believe (it will function at much less or more).

Please note I am not guessing on this, I am asking you to follow the same steps I would use in this situation.

[tuekwik]

By unplugging the injectors one at a time, what is it I'm looking for? Also by removing the valve core and using the tubing, without a pressure tester, how will I know if I have enough pressure?:confused:

[sickrick]

By unplugging the injectors one at a time you will eventually remove the one from the circiut that has the direct short in it that is causing the entire batch not to fire.
Start by unpluging one injector and trying to start the truck, if it won't start plug it back in and disconnect another. Repeat until the truck starts or or you have tried all 8.

Once you have done this you have removed the injectors as the probable source of the problem. This works on all most all fuel injection systems that are batch or bank fired.

How well you know when you have enough fuel pressure?

Have your helper stand 8 feet away from the truck and hold his mouth open. If you can fill his mouth with gas in under 30 seconds you have enough volume and pressure.
Oh yah don't do this while smoking, safety first!

If you suspect pressure is a problem I will tell you what to do later.

[tuekwik]

Thanks for the help sickrick, I will try the injectors tomorrow, I'm burned out on this truck today.:cool:

[McClintock]

heres a stab:

We had this problem on Geoff Falzones (1991 4.0 ranger) truck. For some reason after the truck's battery would die, the truck would never turn over. Unplug the secondary computer, plug it all back together, and try starting it. Not sure why it does that, just a FORD flaw.

[sickrick]

tuekwik,
in the morning go to the auto parts store and get some starting fluid.
remove the intake hose from the throtle body and open the throtle and give it about a 3 second squirt, hop in and try to start it right away.
If that doesn't get it to run for a few seconds then we need to go down another path with this thing.

We will get this thing running just bear with me and do it step by step.

[EQuin]

My 86 Bronco sat for a year. I got it to start by changing the starter solenoid/relay on the passenger side fenderwell. Don't know if that could be something to look into since you said you were getting spark, but thought I'd throw it in there.

Also, with a 91, do you have an E4OD tranny? If so, check the manual lever position sensor (MLPS) by the tranny shift cable on the driver side. It acts kind of like a neutral safety switch. If it's damaged, or not working right, it'll keep your truck from starting. My 93 Bronco (with E4OD) hasn't been working right, but if I rock the Bronco back and forth til the tranny clicks into park, the MLPS will finally sense that it's in park and allow it to start.

Hope this helps.

[EQuin]

Oops. Never mind the MLPS. I just re-read your first post where you said you tried to "crank" it a couple of times. Do you mean to say that the engine cranks over but won't start? If so, then it's probably not the MLPS. When my MLPS acts up, it won't even let the engine crank. I can hear the fuel pump turning on, but it just won't crank. Just thought I'd clarify that.

[FlyHiFlyLo]

Try this, Located in the grill area just in the middle, there is a blue oval. take a #2 standard screwdriver, pry it off. In it's place using a glue gun...Put on a Bow Tie. Should start right up.

JK... LOL

[tuekwik]

I used the starting fluid and it ran but died after burning up the starting fluid.

[sickrick]

Thats great! At least we know the ignition is working properly and that the cam and timing chain are still where they need to be.
After you have ran a couple of quarts of fuel out of the schrader valve its time to start checking the injectors. Just for fun swap the horn relay for the pump relay and give it a try.

[ChuckH]

Long distance auto repair, very entertaining.

The starting fluid test was a good clue

[tuekwik]

I can hear the pump kick on when I turn the key.

[sickrick]

If you are confident that the pump is working as it should, then move on to the injectors.

[tuekwik]

As I unplug one injector at a time and crank the engine, what am I looking for and how will I know wether the injectors are working properly?:confused:

[sickrick]

It will start once you disconnect the injector with the short in it.

[tuekwik]

I'll try tommorrow again with the injectors, if I can't come up with anything, should the fuel pressure reg be something I should look into? Read a couple posts that the reg might be an issue.

[sickrick]

Just to let you know I would personally make certain that the fuel pump is pumping when the engine is cranking.
I would do this by removing the schrader valve and running out a couple quarts of fuel while cranking the engine over. this is the only way to be sure the pump is working as the engine cranks. I have found several fords trucks that will run the pump when the key is put in the run position but the pump will not pump while cranking.
I do think your pump is probable working but I like to totally eliminate things one at a time.

[tuekwik]

Will try that next, thanks.

[baja_driver]

Try this, Located in the grill area just in the middle, there is a blue oval. take a #2 standard screwdriver, pry it off. In it's place using a glue gun...Put on a Bow Tie. Should start right up.

JK... LOL

too much!! didn't have the heart to write that but was thinking it.

good luck with the repair..sounds like a pump issue..cracked line maybe??

[4oshun12]

Hey Bling Bling did you get that thing started, is it inside the gay-rage...havent seen it outside your house

[FlyHiFlyLo]

Let me try to help. (sorry bout the chevy plug) Chances are it isn't the injectors. if that is the case then all 8 would have to be bad,,,think about it.

You may have an ECM problem. Disconnect all the sensor plugs, MAF, temp, TPS, NO, O2. This makes the ECM get no data in and act like it is WOT. Once it starts begin repluging in the sensors start with the temp then O2,NO,TPS and finally MAF if it dies when you connect any of these that may be the source.

[sickrick]

You must be a Chevy guy. On chevy's they fire one at a time (sequential fire). But on this year ford the injectors fire as a batch if one injector has a dead short it can stop them all from firing. I am not guessing on this. I have personally seen this happen on 3 occasions I can remember. on those occasions the trucks/cars had spark had fuel at the rail and would not run. After disconnecting the correct injector it was a great running 7 cylinder engine. You are correct that it could be the computer or other problems, but I am helping him elimanate all of the other suspect components first.

Heres why I would not bother disconnecting all the sensors. If any of those give the computer a errant reading the computer goes into "limp in" mode and just ignores them, it may not run great but it will run.
You will be amazed at how much crap you can unplug on a ford fuel injected motor from the eighties and early nineties before it will actually quit running.

[FlyHiFlyLo]

You must be a Chevy guy. On chevy's they fire one at a time (sequential fire). But on this year ford the injectors fire as a batch if one injector has a dead short it can stop them all from firing.

I have a vision of Clark Grizwald with one bad bulb in his Christmas lights...LOL

[tuekwik]

tried the injectors one at a time, nothing. i'm having it towed to run a diagnostic and pull some codes. thanks for the help.

[FlyHiFlyLo]

tried the injectors one at a time, nothing. i'm having it towed to run a diagnostic and pull some codes. thanks for the help.

Try disconnecting the Mass Air Flow Sensor.

[tuekwik]

Where is it located?

[FlyHiFlyLo]

It is located between the air box and the throttle body. Should be a 3 pin plug.

[tuekwik]

From the air box to the the throttle body there are two hoses, but no sensor. On the tb itself there are three sensors two are two prong, one three prong that sits on the tb's right side facing the motor.

[FlyHiFlyLo]

It may be in the top of the air box

[tuekwik]

I'ts not on the top of the air-box.

[FlyHiFlyLo]

Maybe your truck has a MAP sensor instead. unplug the two plugs by the Throttle body.

[tuekwik]

Unplugged a sensor at a time, nothing. What I tried was removing the schrader valve that lies on the fuel rail, put a piece of tubing on the fitting going into a gas can and cranked the motor, gas was flowing into the can. So I can assume the fuel pump is working.

[FlyHiFlyLo]

Yes.... but was the fuel under high pressure or just flowing?

[tuekwik]

It was just flowing.

[FlyHiFlyLo]

Should be about 30PSI at the very least.

[tuekwik]

Replace fuel regulator?

[FlyHiFlyLo]

Replace fuel regulator?

cant say for sure. Get one of those adjustable ones.

[sickrick]

fuel pump is working fine. To check the regulator clamp the return line with a small vice grip,be gentle. This will max the pressure, not enough to hurt anything.

[sickrick]

I hate to back track but, have you checked the fuses? The first step to take is always check the fuses (ECM and others).
Truck will run with fuel pressure as low as around 10 psi and over 40 psi. Stock regulator is 27 psi I believe.

[tuekwik]

Price for the reg is $26, I'm just going to replace it. I'm thinking of just getting rid of the stock tank and pump nowand purchase a fuel cell with a pump. Would this work with the existing lines and what kind of cell would be good and what kind of pump would I need? Would the reg still work with this setup?