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PCM Fuel pressure trouble

Sent to Car Experts July 08 03:42 PM

I have a 98 Crown Vic. 4.6. Will not start or begin to start. I spray starting fluid into intake and it starts. Checked fuel pressure= 0 lbs. Replaced intank fuel pump still no pressure. Removed fuel pump relay and had 12 volts into relay. Shorted out 2 pins to run fuel pump driect and 40+ lbs. at fuel rail. Replaced relay and 0 lbs. fuel on rail. I suspect PCM defective. Does PCM tell fuel pump to activate? Does PCM tell injectors when to activate? How do you tell if Pcm has power? Car runs if you give intake burst of starting fluid but this is bypassing fuel pump and injectors. With 40lbs. pressure in fuel rail ans engine running with burst of starting fluid sprayed into intake engine dies as soon as I quit spaying into intake. I believe The injectors are not spraying fule into cyl. because computer not responding. I wonder if computer not telling fuel pump to engage. Would this be the PCM or power to the PCM?

 

Optional Information:
1998 Ford Crown Vic. 4.6 gas

Already Tried:
Replaced fuel pump, Checked fuel pressure at fuel rail. Shorted relay and activated pump to proper pressure. Sprayed starting fluid into intake = engines runs.

Customer (name blocked for privacy)
Status:  Closed   Value: $8
Answer
July 8 6:43 PM (3 hours and 1 minute and 36 seconds later)
         
REPLIEDCheck Mark

Do you have power at both the red and LtBlue with orang wires with the key on?

If you can't access the wires themselves, remove the relay and see if you have power at 2 of the sockets.



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Reply
July 10 1:01 AM (1 day and 6 hours later)
         
Reply to Hammer Time's Post: You answered check voltage on the two leads. Which two leads. The fuel pump is working. I have 40= lbs. pressure at the fuel rail. If I spray starting fluid into air intake the engine will run while I spray. I therefore know the coils are firing. The trouble is the injectors aren't allowing fuel into the cylinders. The PCM controls the injectors. How can I check to see if the PCM has power and see if it does have power that it's working? My suspicions are the diode to the PCM is open. I plan to replace the diode in the morning if the dealership has them in stock. If it still won't start I assume I'll need to replace the computer or the chip "PCM" in the computer. How will I be able to identify the bad component? I can buy a computer at Advance for about 160.00 and the chip for 300.00. They need the old PCM to reprogram the new PCM. If the memory on the old PCM is corrupted then how can I get the data reloaded without taking the car into a ford dealership for a real soaking? The car isn't running so there will also be a tow bill. I worked as a mechanic for 5 1/2 years then as an electronics technician on computers for 31 years. If you can help lead me in the right direction I most readily will pay for yor assistance. I know how to use ohm meters and scopes dsp don't hesitate to explain in technical terms. Forgive me if I am asking too much but I am amazed this problem is giving me such a fit.
Customer (name blocked for privacy)
Answer
July 10 5:26 AM (4 hours and 24 minutes and 23 seconds later)
         
ACCEPTEDCheck Mark

Check for injecter pulse using a noid light (shown below). If the light doesn't flash, check for power at one side of the injecter plug.

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