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That's good it is driveable. Sounds like you've now established that the fuel system is fine (can deliver enough fuel to not stumble), and there is some issue with the timing control. Either run it as is, or dig into that system further.
Well drove to work this morning, almost made it to my building and then cahput....truck cuts off....0 psi fuel pressure....sweet. Anyone have any recommendations for fuel pump brands? Not trying to fork up a few hundred dollars for a Motorcraft fuel pump
Well I went ahead and got the Bosch one, swapped it out and drove it shortly down the road before I had to turn around because fuel pressure was around 25 psi and slowly dropping. So i started looking through the wiring diagram (attached) and noticed the circuit for the fuel tank selector. While disassembling the steering column to start the truck, I never thought to plug the switch back in (I just left the plastic pieces around the steering column and fuel selector off so I can pull the steering wheel and fix the ignition cylinder). Am I correct when I say by disconnecting the switch, I opened the circuit to the low pressure pumps? Causing the high pressure pump to be the only one supplying fuel and potentially burning it up to the point of 0 psi? I know the image is for the 5.0 truck but it should be the same circuitry right?
This is a knock on wood but I never replaced one on my Fords.
In general, Bosch, Delphi and Racor are good.
The last one I bought was a flex fuel pump for a Crown Vic. It was from Oreilly, made in the USA and had a lifetime warranty.
Take a look at your relay and inertia switch too. Got dual tanks?
Yeah I'm going to look at those as well. It's raining off and on here so I'm having to stop midway doing things. Does this circuit question make sense?
To me it looks like the diagram matches what you are saying about the low pressure pumps. Unplug the switch and no power to the in-tank pump. Would that kill the high pressure pump? I wouldn't ask at the parts store if you have to return it.
Oh they'll never find out from me haha too busy today but tomorrow I'm going to go drive it and make sure everything is running right fuel pump wise. If not I'll go warranty the pump out for a new one.
Went through a couple tests from the ford manual (attached) for the TFI module. Confused on results. Test one passed but barely. About 35% battery voltage. Test two failed. I was reading 0.1 ohms across the test points....does this indicate a bad TFI?
To me it looks like the diagram matches what you are saying about the low pressure pumps. Unplug the switch and no power to the in-tank pump. Would that kill the high pressure pump? I wouldn't ask at the parts store if you have to return it.
It must've been that. Plugged the switch in, no more fuel pressure issues
Still curious about the TFI though if anyone has a comment on that
Well I went ahead and bit the bullet and bought a new TFI module. Figured if it isn't the problem, ill have an extra one as back up. Well I didn't get a chance to mess with the truck until around 9-9:30 last night and its looking like I'm going to have to repeat the process.
Pulled the #1 plug, rotated the motor to TDC, and began removal of the distributor. I removed the cap and pulled the wires aside out of the way, disconnected the wiring harnesses from the distributor, removed the hold down bolt and pulled the distributor out. Removed module, replaced with new one, and began re-installing the distributor. I used a paint marker in the beginning and marked the spot on the distributor in relation to block where it was at 10 degrees BTDC. After re-installing the distributor, aligning the mark so it was at 10 degrees, and hooking everything back up, I went to start it up. Cranked it up and it would barely run....felt like the timing was set too retarded. I rotated the distributor to advance the timing as much as I could and it started to run better. I guess this means I installed the distributor gear one tooth off? This afternoon after work I plan on pulling the distributor back out and realigning it so the rotor is pointing at the #1 plug on the cap when I have the #1 cylinder at TDC.
The distributor-mounted TFI module, when the distributor is properly installed, faces forward (toward you when your facing the engine), or slightly to your right.
Reset base timing to 10 degree BTDC with a light, SPOUT shorting bar removed.
Verify timing advance with shorting bar installed.
Check book for exact number of degrees of advance to be expected.
The distributor-mounted TFI module, when the distributor is properly installed, faces forward (toward you when your facing the engine), or slightly to your right.
Reset base timing to 10 degree BTDC with a light, SPOUT shorting bar removed.
Verify timing advance with shorting bar installed.
Check book for exact number of degrees of advance to be expected.
Yeah I had it a tooth off, got it back in correct last night. Base timing is set at 10 degrees and when I connect the SPOUT it advances 20 degrees (30 degrees total) and that's what the manual calls for.
After replacing the TFI, no change....today I plan to go through all of my circuits (specifically the IDM, PIP, and SPOUT circuit) and verify all of my wires are right. I attempted to check resistance across the IDM circuit (TFI connector to EEC pin 4) last night to verify the 22k ohm resistor is in the circuit but wasn't even getting continuity across the circuit After taking a look at the EEC connector, it didn't even look like a had a corresponding wire coming out of the connector at pin 4....
That being said, it was late last night, dark outside....and I had a handful of beers in my system so I may have missed something....idk. I will double-check today after work
Update: Ended up redoing all of the wiring between the circuits and got correct resistances and continuity throughout.
Well I decided to go ahead and buy a new distributor today as a last chance effort. After some advice on my other thread, the PIP signal coming from the distributor seemed to be a likely culprit. Pulled the old distributor, swapped the TFI to the new one, and stabbed it in. Cranked it up without the spout plugged in and checked timing, seemed to be running good. Timing was at about 20 degrees so I backed it down to 10 degrees, plugged in the spout and proceeded to drive it. Drove it easy while warming up, didn't notice any stumbling. Motor got up to temp and I got in to the throttle. No stumbling!! None at all!! Came back to the house, let it sit until the motor was cold and then went and drove it again. NO STUMBLING WHATSOEVER!!!! I guess that was the issue I've been searching for!!
I just want to thank everyone for their help, it's been a long time coming and I couldn't have done it without y'all!! I've learned a lot from everyone in this thread and I appreciate everything!
01-11-2018, 05:46 PM
After taking a look at the EEC connector, it didn't even look like a had a corresponding wire coming out of the connector at pin 4....