A little background first.. Wrecked my 92 f150 4x4 with a 302 in it. I bought another truck a 92 f150 with a 4.9 inline 6 that the owner couldn't figure out what was wrong with it. It misses under idle, black smokes, and runs rough and bucks when driving. So I didn't worry too much about what was wrong at first because I was putting my 302 in it anyways. Now that I have my motor in (which ran perfect in the other truck) it does the SAME THING.

I have swapped over just about everything on the truck. Complete motor, tranny, wiring harness, and ECU. This truck does have dual tanks and both pumps were replaced along with fuel filter and also got the recall parts from the dealership to fix the dual tank overflow problem. (It is the 2 pump setup not the 3 pump low/high pressure one.) My fuel pressure is 44psi with the vacuum line unplugged from the regulator, plugged in it is 35-38. It only bleeds down 3 psi overnight. All cylinders are getting fire, the timing is dead on nuts. Yet it still does the same thing that the original motor did.

I am running out of ideas...

Also the only code it throws is the EGR valve which I have tried unplugging and blocking off, but it does the same thing.

 

Its a ghost in the machine lol. But seriously have you tried to do both KOEO and the KOER tests for codes it may give you a few more that way. Just a thought I am not sure Have you tried changing the fuel filter?

 

I have a scan tool that plugs into the port under the hood. Thats how I was able to see the EGR code. We pulled down both fuel tanks and they were filled with what looked like oil. So I completely replaced the back tank because we couldn't get that one to come clean. Also both pumps and filter.

 

Not an expert but the fuel pressure seems high to me. I would have thought you should have 30-32psi with the vacuum line plugged on and at idle.

 

The fuel pressure is too low. At idle with vacuum line on it should be about 45-50 and 55-60 PSI with the vacuum line off with the engine running.

 

So this could be the problem just have to figure out how I am losing 10-15psi. I have two other f150s besides this one. The one I wrecked for a parts truck and one that runs perfectly fine. The one that runs the fuel pressure is 55psi with the line off. Just kind of weird since I have already swapped the fuel pump, regulator, and fp relay from the wrecked one. Don't know what else is left to replace.

 

Is this for the 300 six cylinder or the 302 V8?

 

So I swapped the fpr from the running truck into this one, grounded out pin #6 with the key on and the fuel pressure is at 38psi, lower than what the other fpr was. Running with the vacuum line disco it is the same.WTF

 

Here are the KOEO codes it pulls

637 TOT sensor circuit above maximum voltage
327 DPFE or EVP circuit below minimum voltage of 0.2 volts.
654 MLP sensor not in park position
552 Air management 1 circuit failure (AM1/TAB)
621 Shift solenoid #1 circuit failure
622 Shift solenoid #2 circuit failure
629 Converter clutch control circuit failure
626 Coast clutch solenoid circuit failure (E4OD)
624 Electronic Pressure Control solenoid or driver circuit failure

I believe these are old codes for the transmission though, because it was just rebuilt and it shifts perfect.

I will get the KOER codes tomorrow.

 

300 six cylinder.

But after reading it I think he has the 302 in it, if so then Lazy K is right, it is too high.

 

Yes it has a 302 now, originally a 300.

 

I have a 1992 f150 with a 5.0 and cant figure out why the exhaust is loading up with gas have replaced the icm plugs and wires new coil pack so she is running good and hot. she cranks great at first but loads up on gas and when u kill her she wont restart