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Discussion Starter · #41 ·
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I also got these NOS Sable mats on ebay, I missed the smell of this old vinyl rubber stuff. So good lol. Not bad for 40 bucks shipped given how hard these are to find in 2022. Hopefully nobody is too triggered that this isn't a Sable 馃ぃ
 

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Discussion Starter · #42 · (Edited)
Aaaaaaaand it's dead again. Started up normally and then just died, lol. This would explain why the random longer cranks and general weirdness once in a while wasn't solved with the new fuel pump. The car was starting really good and running great the day before, and then boom. I also did notice some discrepancies once in a while in the data stream that were hard to explain. Could never get my physical gauge on it because the alternator is in the way. But I guess that mystery is solved. Now, I'm aware this code can be caused by the fuel pump, but typically when that happens you'll get a pressure reading that's below spec. In my case, key on engine off reads 62-65PSI. I suspect the sensor is reading high versus actual. The fact fuel trims were always negative is extra evidence towards this theory. New sensor was $70, was actually able to find the only one available locally. It's a unique design to 2000 that's integrated into the fuel rail quick disconnect unlike the later cars. I'll swap it out tomorrow, then find out what's next lmao

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Discussion Starter · #43 ·
Welp, I guess I should have compared output voltage to what the PCM was seeing. Seems like the heatlh of the PCM has gone severely downhill recently. I wonder if I have some leaking capacitors or something similar. It ran great with the new sensor for one drive cycle, everything worked properly. Then the next restart it was flashing antitheft at me and refusing to start. Eventually it did, but it ran the whole time with the fuel pressure value maxed out. This is definitely the most temperamental Taurus I've ever seen. I know it's old, but it's like it's trying to die....

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Discussion Starter · #45 ·
Does the fuel system in your car use a return line for pressure regulation, non return or the one year only three nipple fuel filter?
It's returnless with the electronic FPDM. With the original sensor I was able to catch it acting up, where it kept not building any fuel pressure despite me hearing the pump prime and would crank no start. Then magically it fixed itself and would start and run fine. Went ahead and checked fuel filter, clean fuel coming out (it's new). Replaced sensor, logged data. Values were correct, car drove perfectly fine. Then shut it off at the grocery store and when I went to restart, all these codes popped up and it refused to start with flashing THEFT light. Waited a bit and then it started, but fuel pressure just read 87-90PSi the entire drive home, thus the P0193.

I mean, it's possible that the new sensor died that quickly, but given the other symptoms it seems like there's more going on. I'm going to check all my ground connections and do a voltage drop test again, but when I did that stuff before it all checked out. Will also test the battery as well. Ultimately I think I'll have to pull and inspect the PCM for anything obvious, like leaking capacitors. Wiring fault is also technically possible, but rather unlikely given how intermittent the problems have been and the various circuits involved.
 

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Discussion Starter · #47 ·
Possibly a broken trace in the PCM also. Or cold solder joint on the connector to circuit board trace.
Yep, also very possible. Hopefully it's repairable. I don't have much time to get to it this week, so I suppose I'll post back if I find a smoking gun, or if I throw in the towel. Pretty amazing how so many different problems can pop up in a row, lol. It's not even something I did, after I buttoned up the engine after the valve spring job, I had several trouble free trips and was even able to pass emissions with it.
 

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Discussion Starter · #48 ·
Welp, after doing some more testing and thinking, it's looking like my brand new Airtex pump assembly is the culprit after only a few hundred miles of use. The PATS error with the PCM seems to have been a fluke, I can't replicate it. Using Forscan the PCM easily passes its key on engine off, and engine running tests without any errors (other than a P0411 for secondary air injection performance, but I never see that in actual practice so its not worth worrying about). I found a 200mv loss on the grounding wire from the PCM to the engine block, so I will address that (and I swapped around the PCM power relay in case it's getting sticky). But otherwise the main issue seems to be random loss of fuel pressure.

It's funny too, because in my haste to replace the fuel pressure sensor, I didn't really properly comprehend what the data was telling me beforehand. The new sensor is actually defective, as once the engine warms up to operating temperature and you shut it off, the pressure value immediately goes to 90PSI and stays there, which is either extremely high resistance or an open circuit. I plugged in the old one real quick and it read 0 as it's supposed to (since it's not connected to the vehicle), so that means that P0193 can basically be ignored, the new sensor is junk. I never got that code before swapping it either, so further evidence that the circuit is fine.

With the old sensor, sometimes with the key on, engine off I would see 80PSI, which always seemed way too high to me, but I ignored it because I couldn't find any real data on the flex fuel system specs. I should have known that would end up being a problem, since with the OEM pump it never crested 60PSI key on engine off. It worked once the engine was running, but clearly this pump assembly had trouble managing its deadhead pressure level. The relief valve in the pump shouldn't have let it get that high. Now it seems the problem is the opposite, I never see deadhead pressure that high anymore, but instead I'm getting a rapid 0PSI either right after the engine starts, or when I initially prime it. I always hear the pump making electrical noises when I turn the key to on (and it makes a different noise when it actually builds pressure), so its working electrically, but the fuel doesn't seem to be getting where it needs to go. I checked the filter for restrictions and nothing came out, just clean fuel. Once the pump actually does come back to life, it produces proper running pressure of 40PSI and stays on indefinitely until I shut the car off, and the car drives fine. My guess is that pressure relief is now sticking open sometimes, and once it does finally close and let the car run, the pressure stays low enough to keep it from having to open again. With priming, the car is asking for 75% duty cycle which seems to be overwhelming this relief. Just a theory though, no way to know without pulling it out. I have ordered a new OEM pump. In the mean time I'm going to run some tests on the driver module, but so far I've seen no evidence it's not doing what it should, nor are any codes being popped that would point to it as a culprit. The fact the car stays running indefinitely once you can actually get it started and that the pump duty cycle (20% at idle) seems appropriate is also a sign of good health of the overall fuel management circuit.

This car has definitely been the most challenging of the Taurii I've owned, and I've also never had this bad of luck with aftermarket parts before. But you definitely get what you pay for I suppose (despite those Carquest pumps being $350 lmao). Luckily for me I need to replace the filler neck anyway, so dropping the tank a second time is only a little bit of extra work. Plus every connection has been greased or antiseized from the first time, so it should fight me far less :) I know that was a lot of text, but if anyone has any suggestions or comments, let me know.
 

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Welp, after doing some more testing and thinking, it's looking like my brand new Airtex pump assembly is the culprit after only a few hundred miles of use. The PATS error with the PCM seems to have been a fluke, I can't replicate it. Using Forscan the PCM easily passes its key on engine off, and engine running tests without any errors (other than a P0411 for secondary air injection performance, but I never see that in actual practice so its not worth worrying about). I found a 200mv loss on the grounding wire from the PCM to the engine block, so I will address that (and I swapped around the PCM power relay in case it's getting sticky). But otherwise the main issue seems to be random loss of fuel pressure.

It's funny too, because in my haste to replace the fuel pressure sensor, I didn't really properly comprehend what the data was telling me beforehand. The new sensor is actually defective, as once the engine warms up to operating temperature and you shut it off, the pressure value immediately goes to 90PSI and stays there, which is either extremely high resistance or an open circuit. I plugged in the old one real quick and it read 0 as it's supposed to (since it's not connected to the vehicle), so that means that P0193 can basically be ignored, the new sensor is junk. I never got that code before swapping it either, so further evidence that the circuit is fine.

With the old sensor, sometimes with the key on, engine off I would see 80PSI, which always seemed way too high to me, but I ignored it because I couldn't find any real data on the flex fuel system specs. I should have known that would end up being a problem, since with the OEM pump it never crested 60PSI key on engine off. It worked once the engine was running, but clearly this pump assembly had trouble managing its deadhead pressure level. The relief valve in the pump shouldn't have let it get that high. Now it seems the problem is the opposite, I never see deadhead pressure that high anymore, but instead I'm getting a rapid 0PSI either right after the engine starts, or when I initially prime it. I always hear the pump making electrical noises when I turn the key to on (and it makes a different noise when it actually builds pressure), so its working electrically, but the fuel doesn't seem to be getting where it needs to go. I checked the filter for restrictions and nothing came out, just clean fuel. Once the pump actually does come back to life, it produces proper running pressure of 40PSI and stays on indefinitely until I shut the car off, and the car drives fine. My guess is that pressure relief is now sticking open sometimes, and once it does finally close and let the car run, the pressure stays low enough to keep it from having to open again. With priming, the car is asking for 75% duty cycle which seems to be overwhelming this relief. Just a theory though, no way to know without pulling it out. I have ordered a new OEM pump. In the mean time I'm going to run some tests on the driver module, but so far I've seen no evidence it's not doing what it should, nor are any codes being popped that would point to it as a culprit. The fact the car stays running indefinitely once you can actually get it started and that the pump duty cycle (20% at idle) seems appropriate is also a sign of good health of the overall fuel management circuit.

This car has definitely been the most challenging of the Taurii I've owned, and I've also never had this bad of luck with aftermarket parts before. But you definitely get what you pay for I suppose (despite those Carquest pumps being $350 lmao). Luckily for me I need to replace the filler neck anyway, so dropping the tank a second time is only a little bit of extra work. Plus every connection has been greased or antiseized from the first time, so it should fight me far less :) I know that was a lot of text, but if anyone has any suggestions or comments, let me know.
I had an Airtex which failed in less than 5k miles but that was on a 2001 with the one year only fuel system.
 

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...brand new Airtex pump assembly is the culprit after only a few hundred miles...
Airtex & Spectra are the worst garbage brands on the market. I wouldn't use their parts if they paid me. When I can't find Ford/MC for my trucks, I only use Bosch (which is the OEM for the truck pumps).
 
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Discussion Starter · #52 ·
Airtex & Spectra are the worst garbage brands on the market. I wouldn't use their parts if they paid me. When I can't find Ford/MC for my trucks, I only use Bosch (which is the OEM for the truck pumps).
Yeah, lesson learned. I guess I'm just paying for this one in time though. Hopefully the OEM pump I picked up works and I can put this annoyance behind me and get some actual miles on this bad girl now that it's basically a new vehicle, lmao
 

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Discussion Starter · #53 ·
Well, I was bored and had time today so I back probed the fuel pump driver module and checked it with my test light. It's actually quite the PITA to get to it, you have to remove the rear seat back to get the trunk liner out of the way. Works properly and sends power to the pump, I hear the pump motor working correctly, but zero fuel pressure. So I'm now 100% confident something in the assembly has failed. I just need a warm day to actually get it moved into my driveway, with how cold it's been it refuses to start at all. When it's at least in the 40's I can usually get it to start and run eventually if I **** with it long enough. Guess I could tow it into my driveway if I had to, but I'd rather not.

I also made and installed a new ground cable directly from the PCM grounding bolt to the body ground directly connected to the negative battery post, to bypass the old and crusty one. Not sure if it will really do anything meaningful, but it makes me feel better.
 

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Discussion Starter · #55 ·
I have been able to start my 2001s with bad fuel pumps by using starting fluid. Seems after repeated tries the engine would continue to run. Not sure why it did but it worked a couple of times until I realized it was the fuel pump. It may have been related to battery voltage.
Good to know, I'll keep that in my bag of tricks. What location did you pick to spray it in? In the past, it would let me start it after a while of key on, key off shenanigans, and then it would stay running until you shut it off. This last time, I got about 21PSI once, and that was all she wrote, just went to straight zero after that. Probably doesn't help that the car is parked facing uphill.
 

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Discussion Starter · #56 ·
Welp, got it to start, and got it pulled into the driveway on ramps and got it done. Fuel pressure in spec now. Was much easier with a trans jack but still took about 5 hours. Replaced the filler neck, gas cap, and fuel filter as well.

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Discussion Starter · #57 ·
Car drives great! But wait, there's more! Apparently the car sat for so long that the drivers side front rotor has substantial pitting/corrosion from being exposed to rain and snow. It was already fairly old, so I'm not too surprised. Pads have almost full life, so it seems like someone did brakes not that many miles ago, but probably many years ago. Ordered a powerstop kit from Rockauto, coated rotors and ceramic pads for around a hundred bucks. Much better than the absolute robbery that parts stores are charging now. $60 per rotor? No thanks. I probably won't drive the car too far in the meantime, since you get a nasty grind/pulsation feeling through the pedal under braking, and the drivers side rotor is definitely getting hotter than the passenger side. Not enough to destroy anything (yet), but excess heat is never a good thing for your caliper or wheel bearing.

Brake job incoming! At this point I've just embraced the endless work, gives me something to do I guess...
 

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...the endless work...
馃槅馃ぃ馃槄 You say that as if you expected maintenance to decrease as the car passes 20 years old!
 

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Discussion Starter · #60 ·
The rest of my brakes should be here today. Doing fronts and the rear drums, and replacing all the nasty old fluid. The winter storm had them locked up tight somewhere in Wyoming, which is understandable.

In the meantime I installed some SP-500 OEM spark plugs, since a member on here brought up a good point about heat ratings. I swear that after that the car runs just a little bit nicer (probably because I actually gapped them properly this time), and the heat is hotter than I remember it being. But it's probably just placebo. I know in theory a "colder" spark plug evacuates more heat into the cooling system, but I doubt the difference would be enough to notice. Either way, after a 40 mile highway drive I was being roasted out of the car, lol.

After more testing the brakes are all heating and cooling pretty evenly, so there was no real emergency.
 
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