4.6 Not Starting. Need Ideas!

[Deleted member 87397]

Hey all I'm a 5.0 guy so I don't troll here too often but I'm having issues with an old 95 Crown Vic that has the 4.6 SOHC. I thought you all over here could give me some ideas.

Here are the facts:

Car was running great yesterday when it was turned off. Now it won't start.

Car has over 200k and burns a bit of oil.

Battery is strong and starter is cranking perfectly

Car has had a bad DPFE sensor for 2 years. Replaced it last night just in case that was an issue. (it's my bro's car and he was too lazy to change it.)

Fuel pump primes when key is turned and sounds pretty strong

Fuel will spray out the schrader valve when cranking.

All 8 plugs are brand new

Wires are in great shape and all 8 wires are getting excellent spark

Air filter is clean and throttle body is not gunked up at all

Car will start for a few seconds with starting fluid but runs like hell as if timing were off or a cylinder was down.

All sensors are plugged in

Engine has no major mechanical issues that I know of.

My only other thoughts are maybe a bad crank or cam position sensor or maybe the ecu. Is it possbile that the EGR could be gunked up bad and causing issues?

Any ideas would be greatly appreciated, as I need to get this car up and running soon. Thanks

 

[the98stang]

Car has had a bad DPFE sensor for 2 years. Replaced it last night just in case that was an issue

This HAS to do something with it since it was running last night UNTIL you changed the DPFE....put the old one back in....

Also, you you change/mess with anything else besides that part?

 

[Deleted member 87397]

No. The DPFE was swapped out after the fact. I don't believe it is causing the no start problem.

 

[trombonedemon]

What does DPFE stand for by the way?

 

[Deleted member 87397]

What does DPFE stand for by the way?

Differential Pressure Feedback Exhuast Sensor. Also called an EGR pressure sensor.

UPDATE: I tested the ignition control module at lunch today and it checked out okay, although it buzzed a bit while on the tester. Not sure if that is normal or not. Put the control module back in and got it to start and chug long enough to throw a code. It came back P0320 which is a crankshaft position sensor. I changed it out and it is still having the problem. Now it's possible that the sensor I got was just crappy cuz its just an auto store house brand sensor. I might try swapping the sensor for a Ford one just to rule it out. If that's not it maybe the module is on it's way out even though it tested good or I have a damaged reluctor wheel or the timing chains may have slipped a bit due to old age. Whatever the case may be I'm at least on the right track now. I really hope it's not the reluctor or timing chains. Too much work.

 

[the98stang]

definitely try the ford sensor....

 

[Deleted member 87397]

Thank. Will do.

 

[jomull55]

is it throwing any codes?

 

[Deleted member 87397]

0320. Crank position sensor. Tried a new sensor. Still not working.

 

[lazerred02]

If the sensor is new and you know it in fact is good and working then you need to start looking for a wiring issue.

 

[bnmc98]

Is you IAC working properly?

 

[the98stang]

0320. Crank position sensor. Tried a new sensor. Still not working.

is the code at least gone?

 

[Deleted member 87397]

I cleared the code but it won't run long enough to throw another one. It just runs like the timing is way off on the rare occassions that I can get it to start for a few seconds. I know that the crank sensor on this particular car sends its signal to the ignition module so I'm going to try and find a wiring issue buy I honestly don't think that's what it is. At this point if not wiring it's gotta be a trigger wheel or timing chains. I've checked everything else. The car isn't worth putting the money and time into new trigger wheel and chains either. I might just part it out.

 

[GT Tommy]

Here are two things that I would check on!

First, since you replaced both sensors. Remove the wire connectors on both sensors, and look at the terminal pins. Make sure that none of them are bent out of position. I would then install a fuel pressure gauge on your fuel rail. Just because you do have fuel present, that does not mean that you have the right amount of pressure to get the engine running correctly. You must have between 35 psi and 40 psi for your engine to idle correctly. Hope this hepls. Good luck, Tommy.

 

[Deleted member 87397]

I suppose it couldn't hurt to put a pressure gauge on the rail. I already checked the terminal connections for bent pins, I have pressure at the rail, new pressure regulator and when it does start and chug for a while I can bascially smell raw fuel coming out the tail pipe because it's either not getting spark or the spark is not happening at the rght time. Since all wires are getting good spark, I believe it's a timing issue related to the crank sensor. I even tried a crank sensor from Ford in case the auto store one I got was junk and there's no difference. I'm going to trace the wiring from the sensor to the module and see if I get lucky but I doubt
it. Thanks for all the suggestions everyone.

 

[TheSalad]

fastfox86, did this issue get resolved?