kishy's 1985 Country Squire

[DerekTheGreat]

Ah, tank on the ground, fuel pump out scene. Fun times, that was me about a month ago. I'm sure you'll get it sorted out. Doubt you'll pull your hair out like I did.

[kishy]

Uhhhh, OK, something bigger is happening here.

I returned to the car yesterday. First order of business was to replace the fuel filter. I have records documenting two previous new filters on this car: in the initial batch of work at 74k km, in 2023 at 93k km, and now at 103k. I think the filter was fine, but I had one and it's just that much easier if the pressure is already bled off to start.

I bench tested, and then installed the new old stock Ford OEM Bosch NAPA fuel pump and hanger assembly. I only have one wagon, so the part sitting on the shelf doesn't do me as much good as installed in the car. While doing so, I disturbed the fuel gauge sender in some way that made it start leaking while the tank was laying on that side, so I may have to revisit that, but that is doable while installed in the car. The fuel level in the tank is well above the fuel pump strainer so plenty to run on.

I rigged up the tank under the car with all connections attached. Pressure gauge on the test port. Priming (though it took several attempts, I suppose likely due to air) did get me to just shy of 40PSI which is good. Cranking resulted in shooting a fireball out the open air cleaner, with some coughing but no actual running. It appears I may have jumped the gun on the fuel pump diagnosis.

Swapped TFI with known-working. No change.
Swapped coil with known-working. No change.
Swapped both items back to the previous parts. Key was off during all of those connects/disconnects.

Codes are:
KOEO:
85 CANP circuit failure (never seen one of these before)

CM
14 PIP circuit failure
18 Loss Of Ignition Diagnostic Module Input To PCM/SPOUT Circuit Grounded
22 Manifold Absolute Pressure/Barometric Pressure Sensor Out Of Self Test Range

I'm not sure I've ever seen a 22 before. I swapped with a known working MAP, no change.
The problem with 14 and 18 is, as I recall, a failed start attempt can set them even if they are not the cause. e.g. the computer thinks something along the lines of "everything was working but suddenly I lost RPM input so I set a code for a circuit failure" even though the RPM input was lost because the engine stopped turning.

That being said, at the moment I'm leaning towards the engine either jumping time (re: spat fire out the throttle body), the PIP being faulty, a harness fault, or failed ECM.

How does this explain the lack of fuel pressure before? Not sure. There definitely wasn't 40PSI at that port when I poked it on the roadside. The ECM runs the fuel pump both at prime, and also each time it sees one revolution of the engine, so essentially it just runs a series of those 2 second primes over and over and over every time the engine turns. If the ECM isn't seeing RPM or is seeing it erratically, it may not have re-primed the pump after the injectors opened and bled the pressure off. OTOH, how are the injectors opening if the ECM doesn't see RPM? The PIP does everything - it's how the TFI knows to spark the coil, it's how the ECM knows to open the injectors, and it's how the ECM knows to keep running the fuel pump. It seems like it's occasionally doing all of these things but maybe at the wrong times.

I have a feeling this is going to get more complicated before it gets better. I think I've got a PIP on the shelf, but I think my only spare whole distributor is for a roller cam so I can't just pop that in as a unit.

Upon making the discoveries noted here, I went ahead and bolted the tank back into the car. I still don't like the fuel pump wiring but it's clearly not the problem, and this way the car is in one piece, ready to go, in case the next step involves a trailer.

[sly]

Bah and humbug. Hopefully it's not a bad jump in time if that is the issue. This is definitely not going to be a quick fix. I would try a known good ECM and dizzy. I wish these vehicles had an inspection port to borescope the timing chain.

[Kodachrome Wolf]

At least verifying jumped timing isn't terrible, assuming the balancer hasn't slipped at any point.

Hopefully its not the ECU... have you ever recapped your existing one or is it still original? The handful of "properly borked" ECUs I've seen were on SEFI cars, which while they ran, ran poorly and the diagnostic port would not respond. Still, guess it's not outside the realm of possibility at this point.

Certainly curious to see what happens further on in the diagnosis.

[gadget73]

The pump won't run when cranking if there is no PIP signal, but it will prime just fine. Jumping timing or having the chain fall off completely won't set a PIP code either as there is nothing for the ECM to reference the crank position relative to cam position. That won't make it not make fuel pressure either but it will crank like its got no compression.

CANP code probably means either the CANP control solenoid is unplugged, bad, or just has a broken connection. its usually looking for +12v on the control line. It grounds that circuit to turn the thing on, so it should see +12v when its not being commanded active. That shouldn't cause any problems unless for some reason all or some of the +12v ECM circuit is dead. That will keep the injectors from being able to fire. All of the solenoids on the valve cover and the thermactor get that supply, maybe worth poking a voltmeter in there to see if something has failed in that zone.

[87gtVIC]

Following your struggles. It is interesting to read and suspenseful at the same time. Looking forward to what you come up with next in your diagnosis.

[87GrandMarq]

I’m not familiar with wagons but don’t the cfi cars have two fuel pumps? Isn’t there a high pressure pump inline on the frame somewhere?