94 4.6 Grand Marquis No Fuel Pressure
 

Greetings, hope all is well everyone!

I am having a small issue that has me stranded with my daily driver, yesterday was the beginning of this dilemma; going roughly 45mph down the highway the car began to back fire and sputter.

I immediatly pulled it off the road and it died soon after, the only thing obvious I could find under the hood was a vacuum leak behind the intake manifold(which is now been fixed). I was able to get it started back up after fixing the leak but the car continued to run poorly and ran another block or so before dieing out again, from that point cranking was of no avail as it would just turn the engine over but not crank. It sounded almost as if it was flooded or had no fuel at all.

This morning I went out to get started with it, it will still turn the engine over fine when cranking but there's no hint of it starting. I then checked the fuel pressure via the fuel rail check valve, there was NO pressure whatsoever with the key in the on or starting positions. So far I've already checked the trunk switch and it does not appear to be tripped as the red button still appears to be in the down position and cannot be pushed any further. Further more the fuel pump doesn't seem to make an noise of engaging when the key is turned over leaving me to believe this is entirely fuel related. Outside of a bad fuse or fuel pump is there any elements that should be check which could be responsible for this problem?

Thanks in advance for any help of any kind! I apologize about the long read, trying to be explicative as possible so I can solve this as fast as possible!


Just a note, I have not yet checked the fuses because I have yet to find a 94 owners manual showing a diagram for which; for some reason the manual didn't come with this car when it was purchased 4th handed from grand parents. I've been able to find diagram online, but not for this year and make, so if anyone has a source or reference that would be most helpful in addition to my prior question. Thanks again!

Regards,
Fonzi

could either be fuel filter clogged popping fuse for fuel pump, or pump crapped out... fuse for pump is under the hood in the fuse box ... the box if i remember is marked to which one is for fuel pump... had a 1992 and pump was drawing too much and killed the fuse... i change pump and then found fuse and then it worked

Thnx for response, we've now got fuel pressure, checked all fuses, filter replaced and the pump is engaging, now it's not firing and can't even get a spark with starter fluid in the TB. Power if definitely going to the into the ignition system but doesn't seem to be coming out to the plugs. It will start randomly sometimes if you try it but shuts right back down. I've checked for unplugged wires or poor connections as best as I could finding none. The only problems it's had in the last year or so is the A/C compressor locked up so I installed a bypass but I highly doubt that's related. It's not throwing/posting any service codes either.

have you checked both coilspacks on the car to make sure they are both dead? wish i had more knowledge toward this, but i am used to the 5.0 setup... i would suggest checking out www.fordforums.com ... Bert and a few others know there stuff when it comes to that engine and i help there when it is a 5.0

Beginning to lean in that direction or something with the coils wiring, the coil packs were replaced roughly 2 years(less than 9500 miles, I don't drive much ) ago due to misfiring on several cylinders. The fire/charge is definitely getting to them but doesn't seem to be coming out, though last time I had trouble with coils it didn't seem to "come and go" like this seems to be doing as I can crank it maybe 1 out of 20 tries it will run and even drive around the yard, then right back to back firing and not starting again; it behaves almost like the reaction of air getting in behind the airflow sensor but that's already been check several times. I've not tried the ford forums yet, but will give it a try thanks for the advice, being stuck without transportation is becoming a big problem.:eek:

CPS(Crank Position Sensor) replaced, Fuel pump relay replaced, still waiting on a volt meter to test fuel pump and TPS. Have to borrow one, so far I'm already in over $100 without the issue solved. The CPS seemed to make a difference, it would at least crank and run and idle fine however after running a few minutes it will return to misfiring and backfire eventually shutting down. Could have been more that one thing wrong.

Just a follow-up to this thread, I've fixed the problem after almost 2 months of replacing sensors and testing different wiring and ignition parts along with installing a new pump. The crankshaft position sensor was replaced, but I had not inspected the wire closely when plugging it back in. The copper of both wires were bare to the elements after somehow coming in contact with the a/c by-pass pulley stripping it. Thankfully we had a few extra harnesses here and I was able to splice a new CPS harness into the good wires today, it fired up on the first try. Thanks for the contributions!