1994 Ranger 4.0 V6 cranks but won't start. Tried all the normal things. Grasping for straws here. One weird clue.

[alwaysFlOoReD]

I have no idea what this post has to do with the thread.

Oops. Not sure what I did there.

 

[gw33gp]

It is very common that the anti-backflow valve in the fuel pump is not working properly if the fuel pressure drops off when the engine is turned off. Sometimes you have to try to start it several times before it will fire. Cycling the ignition switch a few times (on and off positions) just enough to activate the fuel pump will build up enough pressure to get it to fire the first time you try to start it.

 

[Ramcharger90]

I fixed a 4.0 exploder the other day the one wire was broke down at the crank sensor. Did you look there?

Its a field truck thats been sitting so mice like to chew on things.

 

[Dirtman]

I fixed a 4.0 exploder the other day the one wire was broke down at the crank sensor. Did you look there?

Its a field truck thats been sitting so mice like to chew on things.

He got it running. Crank sensor is a no start condition.

 

[BrightCalypsoGreen]

I fixed a 4.0 exploder the other day the one wire was broke down at the crank sensor. Did you look there?

Its a field truck thats been sitting so mice like to chew on things.

Yes, I do worry about mice and ground squirrels, but in this case it was not the issue. If you look at the tach and it's showing 100-200 rpm while cranking on the starter, your crank trigger is working.

 

[BrightCalypsoGreen]

UPDATE:



I've got the truck running, so I'm updating this thread in the hopes of helping others. As it turns out, I did have 2 issues. The first was the ignition switch plug popping out. The second was leaking injectors. (Pulled the DIS connector and spun the engine over. Pulled the plugs. 4 were wet. Not terrible but not dry. So this means leaking fuel injectors. ) First one fixed (sorta) and the 2nd one I'm working on.

Here is what I have done to address the leaking injectors. Since the truck sat so long with rank fuel, I poured in 1/2 a gallon of seafoam and let it run for about a hour. I redid my bleed down test. Initially I was going from 30psi to 0 psi in about 30 seconds. After running the seafoam for about an hour my bleeddown was now 3 minutes. Certainly not correct, but going in the right direction. So I poured the rest of the seafoam in (1 gal total into about 8 gal of new fuel, 4 gal of which was Sunoco Optima) and ran for about 3 hours today. Idle, fast idle (2K), revving high, etc. Just trying to get as much treated fuel thru the injectors as I could. I also pulled the vacuum line from the regulator to get more pressure. ie, more pressure more fuel and more force for force the gunk thru the injectors. (capped the port of course.) After about 3 hours of this, my system still drops to 0, but it takes over an hour. Also it'll go down to about 10psi and sit there for a long, long time. Again, more in the right direction.

One thing I know about seafoam is letting it soak over night or even a few days will help as well, so that's what I'm doing now.

If you want to see how to disco the speedo cable from the instrument cluster and/or see exactly how I "fixed" the ignition switch I made a quick video:

I ordered some bulbs for the instrument cluster on Amazon and a new fuel refill hose so once I get them I might actually have a fully functional truck again.

Thanks to everyone here that helped.

Other data (just for my record) Compression test was 180-185psi on all cylinders, exhaust temp at fast idle was 900F +/- 20F on all cylinders at the headers just as they exit the head. (first bend)

 

[BrightCalypsoGreen]

Hello BCG, welcome to TRS

You'll need much better advice than I can offer, and that will likely be overnight.

I can offer this, when you let off the key after it fires up, it switches from the "start" wire, to the "run" wire, AsFarAsIKnow,(AFAIK )

Maybe it's an ignition switch issue

really you had it right from the start. I don't know why I didn't listen. :-/ Thank you.

 

[Josh B]

I would add to that the Seafoam spray into the intake, but be forewarned, it could dislodge debris into your cat converter, which could create further problems(all of which you will still need to address in time)
Thank you sir for the appreciation

 

[Dirtman]

Pulling the injectors is fairly easy. Might be worth doing it and running them through a DIY cleaning kit like this.

Amazon.com: FUAN Universal Auto Car Fuel Injector Nozzle Gasoline Cleaning Tester Repair Tool Flush Cleaner Adapter DIY Cleaning Tool Kit Set: Automotive

Buy FUAN Universal Auto Car Fuel Injector Nozzle Gasoline Cleaning Tester Repair Tool Flush Cleaner Adapter DIY Cleaning Tool Kit Set: Fuel Injectors - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[Mokume]

Hello,

I have a situation I need help with. The truck is a 94 Ranger 4x4 with 4.0 V6 and manual trans. 90K original miles. Just a field truck. It has been sitting for 10+ years. Never failed to start until now. The last time the truck started was about 2 years ago. Recently I went to start it and it cranks but won't start.

Checked plug #1 for spark, it's good.
Checked fuel at the rail, I don't have a gauge it but it squirted out when I depressed the schrader valve.
The gas was old and rank smelling so I siphoned it all out of the tank and put in new fuel. I pulled the stem out of the schrader valve and let it crank over till I saw new fuel coming out of the hose. Didn't make any difference.

I pulled the bed and fuel pump. I checked the hose from the pump up and it's fine. No cracks and it's still looks brand new and is still flexible. No leaks that I could see.
I tested the fuel pressure directly at the pump, 55psi going thru the key on start.
I tried starter fluid (ether). Makes no difference. It sounds exactly the same as trying to start it on gas.
I have no CEL, except when I turn the key to start and then it goes out when the engine tries to start.
The engine tries to start, runs for 1/4 to 1/2 second then dies.
The tach shows 400-700rpm during this 1/4 to 1/2 second.

I checked both relays in the fuse box under the hood, fuel and ecu. Both click when 12 v applied.
I checked all fuses, all tested good. (test light on both sides). Checked all under the hood and under the dash.
I pulled the connection off the TPS, makes no difference. (some have said a bad TPS will cause it not to start.)

I pulled the connection off the coil pack. You can hear a distinct difference. The engine just spins, never tries to start. Plugging it back in you can hear it go for just a fraction of a second and then die. So it appears the coil pack is working. When I checked the spark on #1, it was at good 1/2" long spark.

I checked the inertia switch. It's not tripped. I did not test the connection since I had 55psi at the fuel pump using the original wiring thru the key so it's working.

The WEIRD clue is the radio is dead. Factory AM/FM stereo always worked before but now it's dead. I will double check the fuse on that, but it's just weird. I don't know of a single thing that has a common circuit between the radio and the starting/running circuits.

There was some work done by a local shadetree mechanic a few months before I parked it last time. He replaced the master cylinder and the fuel filler hose.

I replaced the plugs, wires and coil pack at that time. After all of these things were done the truck started and ran fine for a few months. Then I parked it. That was about 2 years go.

I'm told this engine has no cam sensor and I'm told if the tach is showing RPM while cranking the crank sensor is working so I've ruled both them out.

Tomorrow I will check spark on all 5 remaining cylinders.
I will also buy a adapter so I can check fuel pressure at the rail.

At this point my only thought a is fried ECU. The reason I say that is that the radio is dead. I'm thinking maybe the truck got hit by lightening sometime in the last 2 years and fried the ECU. I know that's a long, long, long shot, but it's all I've got at this point. The other option is a really clogged inline factor fuel filter. However the filter sock on the fuel pump looked brand new with no foreign matter on it, sO I really doubt the filter could be that clogged. But once I check the pressure at the rail I'll know that for sure.

If anyone has anything else I should check, please LMK.


Thanks for reading this!

Check fuel pressure at the injector rail by switching on the ignition but not cranking it (KOEO), each time the ign. is cycled to the on position the fuel pump will run for approximately 2 seconds then shut-off.
My 2000 S/Cab 4.0 OHV which sat for 3 years in my car port did the same thing, but in my case the pump was bad. You're measuring 55 psi @ the pump so that rules out a bad pump, but you still need to measure it at the rail.
I sure hope your fuel filter is not the factory original, it was probably replaced at some point in time with a Motorcraft unit.

 

[BrightCalypsoGreen]

Hello All,

I'm still trying to nail down the fuel pressure bleed down issue. It's either the injectors or the regulator right?
Is there some valve in there like a spring check valve on the return line?

And if it's the regulator, then it has to come out the vacuum port right? And I checked the vacuum line and there is no sign of fuel there so I have ruled that out. Unless there is another way for it to leak. (no external gas leak that is 100% sure.)

The fuel filter is the original, never changed. Does anyone know what the pressure should be at the rail? Ie, the "official" number by Ford? What I have is 30psi idling and it's 40 psi with the vacuum line removed. (simulating WOT) Seems like it should be higher but at this point the bleed down is my main issue. Cycling the key a few times only takes it up a little bit. Never more than 40, but as soon as the engine starts it's back to 30psi.

The Seafoam thru the fuel system made a measurable differnce but it's not solved the problem. So how do injectors leak? My understanding is that if the o-rings are bad, we have an external leak. The way injectors leak internally is build up keeping them from closing all the way. Is this correct? Is there some other way they could be leaking? I saw a youtube video where the guy tested an injector and it was like a firehose. I'm hoping I don't have that. (killing the rings for sure if it's that much fuel.)

Does anyone have a diagram of the fuel system? That might help me understand the situation. If there is some other check valve where would that be?

 

[gw33gp]

Either you did not understand what I said in my previous post or you did not read it. There is a check valve (I called it an anti-back flow valve) in the fuel pump that maintains pressure when you shut off the engine. If it leaks back, you lose pressure.

 

[BrightCalypsoGreen]

Either you did not understand what I said in my previous post or you did not read it. There is a check valve (I called it an anti-back flow valve) in the fuel pump that maintains pressure when you shut off the engine. If it leaks back, you lose pressure.

Okay I 'll check the pump again. It's all still apart and easy to do. thanks

 

[BrightCalypsoGreen]

Well in the thread that never ends... I have discovered a leak in the fuel pump line. When I pulled it, I looked very carefully for cracks or any degradation in the hose. To the naked eye, it looks almost brand new.
But today I looked thru the filler port and could easily see the pump and rubber hose. Turning on the key I could see large droplets of fuel coming out of the top of the hose where it goes into the metal line.

So that has got to be replaced with some new clamps. I still may have leaking injectors, but the fuel pump is definitely bleeding down. So that's what I'll do this weekend. :-(

This makes 3 things at once going bad.

 

[91stranger]

I'd like to see a pic of the homemade air intake. Didn't sound interesting until you said you made a box to adjust idle and what not. I just don't see how this contraption would work unless it was like a butterfly valve to control the air flow.... I don't know, but a pic would be nice to see what the heck you made.