1996 f150 5.0
Just did a tuneup, fuel filter, transmission filter change, differential gasket, rear fuel tank, smog pump check valve, o2 sensors, new exhaust and now it has the following issues.

1. Hesitation on acceleration but once moving it goes but adding more power takes time.

2. flashing brights with multiswitch no longer works everything else on it works.

3. Reaks of gas, very strong.

4. new exhaust stinks i hear thats normal?

Not sure whats related or helpful.

Code Im getting is p1751

Exhaust manifold had a crack, welded it up.

 

I think a in depth inspection of the fuel delivery system would be the first step, closely followed by a fuel pressure test to eliminate fuel problems from the hesitation problem.

P1751 FORD Possible Causes

• Faulty Shift Solenoid 1
• Shift Solenoid 1 harness is open or shorted
• Shift Solenoid 1 circuit poor electrical connection

 

I should have just fixed it myself but was pressed for time. The air pump check valve was replaced and it damaged some wires and the guy I had replace it messed with the harness near it. Any idea if that is the main engine harness or some thing else? Its a big bundle of wires at back of engine. Think he completley screwed my truck up. Heres a complete list of what he did and whats wrong that I have noticed SO FAR.

What He did:

1. He cut off replaced exhaust after 02 sensors including catalytic converters. Its just pipe and mufflers single into dual, so I need to redo my exhaust.
2. Welded the exhaust manifold crack until i can get headers or replacements.
3. Transmission Filter replacement.
4. Air pump check valve and wiring as stated.
5. Fuel filter, motorcraft plugs, ford racing wires, msd cap and rotor
6. Replaced rear gas tank, filler neck.

Whats wrong SO FAR lists grows daily:

1. Viper Alarm is screwed and goes off while driving.
2. Hesitation taking off.
3. Jolt when taking off maybe 1 second after hitting gas
4. Rough Idle but around 600 to 800
5. Brights flash on multiswitch no longer works, it's a fairly new unit
6. Ignition switch screwed and spins without key. Fairly new as well.
7. Stereo volume changes with alternator like when accelerating it gets louder decelerating quieter. Never used to.
8. Reaks of gas
9. Sounds like ****
10. Fuel gauges don't appear to be working, I'll know today when I get gas.

 

Wiring on the left.

 

I am thinking the wire bundle you are referring to is the main harness to the engine from the PCM. if that is so it could be giving you problems with readings form some sensors making it to the PCM if it is damaged. It could also be causing some of the fuel injectors not to function. possible that hesitation could be caused by the fuel pressure regulator. When throttle is opened, vacuum supply to the FPR falls lower and will increase fuel pressure to the injector rail to meet the greater demand for fuel during acceleration.

 

Guess I'll be buying a new harness. Know by chance how much of a pain that spaghetti will be to replace?

 

no, I don't. But I suspect that everything that you can remove from the topside will make lots more viewing/working room. the fuel pressure regulator on the 5.0 is on the rear corner of the plenum near the brake vac booster, and pretty accessible for changing. would be easier to change and check if it helps acceleration before going deeper. BTW NICE LOOKING 96.

 

PS a fuel pressure test will tell if the FPR is working properly.

 

I was watching chris fix videos on testing fuel pressure I'm learning still but It seems easy enough. Just don't trust anyone locally anymore after what happened here. Thanks for your help! I'll check everything out.

Thanks! Other than taking it to this guy I took really good care of it. Got a great deal in 04 from first owner and up until last year it never gave me problems. Damn good truck!

 

In case you need to do any circuit testing I'm sending you this link to 1996 OBD II PCM pin out chart. Any replacement harness for the 96 5.0 must be that specific model. https://troubleshootmyvehicle.com/fo...in-out-table-1