[Arron in So. Indiana]

First Time Poster/Long time trying to figure this out on my own Reader!!!

I have a 1995 Mercury Cougar XR-7, with a 4.6 Liter V-8, that has 157,000 miles on it. It has been regularly maintained. It is running awful and showing codes for Cylinder #1 misfire and Cylinder #5 misfire.

It has been to 2 Ford dealerships and been examined by 2 other experienced certified mechanics. It has left several people pulling at their hair, trying to figure it out.

1 Ford dealership mechanic couldn’t find an exact problem and suggested I replace the engine – I’m not ready to accept that answer.

The other Ford dealership mechanic said that it had a bad intake valve, so I had a scope ran in the cylinder and found no bad valves.

1 Certified mechanic said he ran every test he possibly could and could find nothing wrong with it and said that theoretically, the engine is in perfect order and should have no problem, that he could find and that he couldn’t help.

The other certified mechanic ran all the probes and even used a Sun machine on all the electrical leads and it came back in normal parameters and that he couldn’t determine the cause of the problem.

Here is a list of things that have been done to rule out problems:

1. Plugs and Wires
2. Cleaned EGR and EGR Passage
3. Swapped injectors and bought 1 new one
4. Changed Plenum and Intake gaskets
5. Changed Coil Packs
6. Changed Ignition Control Module
7. Changed the fuel filter
8. New Mass Air Flow and Air Flow Sensor/Switch
9. New Throttle Positioning Sensor
10. A Compression Check – Holds 178 to 180 psi in every cylinder.
11. Had voltage check on every injector and every sensor on the car by all 4 mechanics.
12. Checked fuel psi and it is within parameters.
13. All of the plugs get fire – Cylinder #1 plug is a little wet from fuel and cylinder #5 plug is a little black.
14. Checked cam lobes and they are good
15. The car ran fine – I shut it off at 11:00pm and the next morning I started it up and instantly had a cylinder #1 and #5 misfire.
16. While the engine is running, you can unplug either injector for Cylinder #1 or #5 and it still has the same miss.

Can a computer be causing the problem? Any ideas of where to go or what to do next? Any insight would be sincerely appreciated.

Thanks - Arron

 

[twin turbo 281]

are you sure its not the coil packs or it could be an ignition problem. cyl #1 and #5 are both fired from the same coil/channel? Im not 100% on that Id have to go look

 

[Arron in So. Indiana]

I swapped around the coil packs and it did not run any different and then replaced them and still have the same problem. I don't know about the ingnition. What should I look for or do if that's the problem?

Thanks for the input - Arron

 

[General Zod]

6. Changed Ignition Control Module

what exactly do you mean?.......did you replace the relay box behind the passenger side headlight, or, did you replace the Electronic Distributorless Ignition System (EDIS) module that rests on the front of the passenger shock tower, behind the airbox?

16. While the engine is running, you can unplug either injector for Cylinder #1 or #5 and it still has the same miss.

either the injectors are not opening, or staying open, or the spark is not getting there.....the 94/95 EECs are known to have faulty injector drivers.......if you place a flat blade screwdriver firmly on the injectors, can you feel them click as they open/close?.....if you don't "feel" them click like the other injectors, then its the EEC, since they are controlled directly by the EEC.......if you take the plug wire off the cylinders in question, and hold them near a grounded part of the body, can you see them arcing the electricity straight to ground? if not, then the EDIS module or the EEC may be responsible for that

 

[lightevergreenfrost]

I would bet on the injectors. Heck, you have replaced everything else.

 

[timb]

I would check out the EDIS it's the electric box mounted on the passenger shock tower above the MAF. Try to get one off another car to swap as a test because they are pricey

 

[Arron in So. Indiana]

what exactly do you mean?.......did you replace the relay box behind the passenger side headlight, or, did you replace the Electronic Distributorless Ignition System (EDIS) module that rests on the front of the passenger shock tower, behind the airbox?





either the injectors are not opening, or staying open, or the spark is not getting there.....the 94/95 EECs are known to have faulty injector drivers.......if you place a flat blade screwdriver firmly on the injectors, can you feel them click as they open/close?.....if you don't "feel" them click like the other injectors, then its the EEC, since they are controlled directly by the EEC.......if you take the plug wire off the cylinders in question, and hold them near a grounded part of the body, can you see them arcing the electricity straight to ground? if not, then the EDIS module or the EEC may be responsible for that

Sorry, please understand that I am basically an old style pre-computer guy...I replaced the EDIS, not the relay box behind the passenger-side headlight. I checked the injectors and they all seem to be similarly clicking. I am getting spark from all plug wires. I also noticed that the car will also start and run without the mass air flow sensor plugged in. It runs the same either way. I have swapped out 3 different mass air flow boxed and switches. Is there some connection there?

 

[tlpru]

very interesting problem...

have you swapped your injectors around.....

could be a computer problem.... (false code)...

with a two cylinder miss fire....you will know that.....

go for the computer...

my 2 cents

trent

 

[Arron in So. Indiana]

All of the injectors have been swapped around, with no difference. I even purchased a new injector, to add to the swap, with no change.

 

[timb]

Perplexing. I didn't notice you had replaced the EDIS. I hesitate to say do this or that because you have checked a lot of things and replaced just about everything you can think of. Couple of longshot items
1. Do you have any moisture in the two plug holes with problems like from a leaky hose?
2. Check the condition of the ground strap running to the motor (lower drivers side of block)
3. Ensure the connector is seated well at the crank trigger

 

[91TwighlightGT]

Have you checked the wiring to the fuel injectors? Just throwing that out there...

 

[tlpru]

your going to have to trace back.....

what controls the injector....start there...(the car is running fine)...there is no mis fire.....look for more sensors but,

its sounding more and more like a computer problem...


trent

 

[timb]

It's easy to check if the injector drivers have failed in the EEC. Just check the voltage at the injector and see if it's constant or pulses like it should. If you have constant voltage at any of the connectors replace the EEC and you should be good to go.

 

[Chris_Murder]

I agree with timb, check the voltage of each injector lead with a multimeter while the car is running if one doesn't pulse its your eec