87 F150 Won’t Start

[Mhfco6]

What engine in this truck?

There is no Fuel Pressure Sensor, so pumps may be shutting off but not because of pressure

Do not try to start engine
Jumper the OBD1 fuel pump slot
Turn on key
Watch pressure at the rail, should go up to 42-44psi and FPR will open and fuel will start to flow back to the tank, pressure should remain at about 43psi as long as key is on, and pumps should stay on the whole time
If pressure goes above 45psi then FPR is bad, assuming pressure gauge is acurate

FPR has a vacuum hose attached, check it for gasoline, shouldn't be any of course, if gasoline is in that hose then engine is being flooded out because of leaking/bad FPR

4.9 i6 300
Gauge stops at 55psi, pumps still running.
There is no gas smell or fluid in vacuum hose.

 

[RonD]

4.9l I6 is a little different, or so I have just read
The 5.0l V8 and all Ranger pre-1998 were 35-40psi

Fuel pressure for 1987 4.9l should be 45-60psi
But I did see a couple of references saying all 4.9l EXCEPT 1987, so confused, sorry

So you are OK
Start engine and watch what pressure does

 

[rusty ol ranger]

If you change the ECM and selector valve i about bet youll be fine

 

[Mhfco6]

Over night the pressure gauge dropped to 12psi. I tried to start the truck on that and no go. I turned the key on/engine off and jumped the fuel relay. The pressure went up to 55psi. I sprayed starting fluid in the TBs and started the truck. PSI didn’t fluctuate or anything, just slowly crept downward till around 48psi. Here is a video:

 

[rusty ol ranger]

Check your injector grounds.

 

[Mhfco6]

Check your injector grounds.

Injectors have power but no ground. No pulsed or any signal when truck is fired on starting fluid.

 

[rusty ol ranger]

Injectors have power but no ground. No pulsed or any signal when truck is fired on starting fluid.

The ECM grounds the injectors out to fire them. So if the wireing is good its the ECM.

 

[Mhfco6]

The ECM grounds the injectors out to fire them. So if the wireing is good its the ECM.

Ten-Four, I will get one ordered up since I’m not sure what exactly is wrong inside. Any idea why such a big pressure drop overnight, FPR to blame?

 

[rusty ol ranger]

Ten-Four, I will get one ordered up since I’m not sure what exactly is wrong inside. Any idea why such a big pressure drop overnight, FPR to blame?

Its a return system...so yes it could be...could be a injector stuck (very) slightly open or it could be that pittsburgh fuel pressure gauge...i got one too and it isnt the greatest lol.

 

[Mhfco6]

Its a return system...so yes it could be...could be a injector stuck (very) slightly open or it could be that pittsburgh fuel pressure gauge...i got one too and it isnt the greatest lol.

Haha, you right! I’ll throw a good gauge on it and see what’s up. In the meantime I’m going to be looking a for a computer. No parts stores recognize the L2C code on the computer, only the other #s mentioned in previous post. I’ll have to try and find a code specific chart to show which firmware etc was oldest/newest. The L2C are on eBay for $200-$300.

 

[rusty ol ranger]

Since yours is an 87 and 87 was the first year for an EFI 300 yours is probably the least "desireable" ecm. Atleast i would thinm

 

[Mhfco6]

Since yours is an 87 and 87 was the first year for an EFI 300 yours is probably the least "desireable" ecm. Atleast i would thinm

So how do I know which part ECM# I is compatible with the one I have so it will work correctly?

 

[rusty ol ranger]

So how do I know which part ECM# I is compatible with the one I have so it will work correctly?

That i dont know.

But any of them for a 300 from 87-95 with federal emissions and your trans should be fine. 96 trucks were OBD II and MAF.

 

[Mhfco6]

There are about 20 different codes to choose from on this model/engine truck. NAPA was the only one that came close to helping. Ford said it’s discontinued and the last known engineer code is E8TZ-12A650-CKA. NAPA is going to contact their seller and give them my VIN and mileage to find out which computer(s) are compatible. I will hopefully know more tomorrow.

 

[rusty ol ranger]

There are about 20 different codes to choose from on this model/engine truck. NAPA was the only one that came close to helping. Ford said it’s discontinued and the last known engineer code is E8TZ-12A650-CKA. NAPA is going to contact their seller and give them my VIN and mileage to find out which computer(s) are compatible. I will hopefully know more tomorrow.

I think you would be fine as long as you stay with the same engine/trans.