New Remanufactured PCM? not the problem i thought it was?
My 94' v6 3.8L messed up on me for the second time in under 7 months. The first time i had problems (7 months ago), my PCM burnt out. i experienced rough, and inconsistnt idling. My pipes, consisted of white smoke with gas spraying out (left Pipe mainly). I figured one of my fuel injectors was stuck open. i did a great tune up of my car, replaced my fuel injectors, cleaned my sparkplugs, got new plug wires, cleaned my fuel lines, replaced my gas filter, and changed and replaced the oil and filter . i checked the fuel pressure of each cylinder as well. Problem still existed, so i was told to grab a used PCM and replace it. did that and car worked eversince.
Now, my car displays the same exact signs and symptoms. i turned my PCM back to get it remanufactured. I replaced it, and installed it back in. Relieved (both wallet, and I) that the problem was fixed, i started the car. The car sounded fine at first, but gradually got worst. the engine went back to clugging, and the poor idle appeared again.
What is happening to me??
I figure i should check into the fuel injectors again?
Maybe check the reman'd PCM? that should be working..i dont know.
any suggestions?
seems to me if the electrical aspect has been attended to on more than one occasion and all the wires/hoses/clamps/filters are secured, in the right place and in good working order... it's probably something mechanical with the engine itself... I'd look into the timing like Keith said... what kind of work has been done to the engine itself?
Would the Incorrect Timing have the same indications and symptoms of what im experiencing right now? ( rough/poor idle, white exhaust smoke, and gas spray)
If this is a potential conflict, how would i go about investigating it further?
Were you able to locate which cyl. had the affected injector? Using a fuel pressure guage its very easy to find it.
Incorrect timing is unlikely unless you have messed with the cam synchronizer, not saying its not possible, just unlikely. Plus timing thats slighlty off will not have that large of an impact, especially pushing raw fuel through the exhaust.
It seems to be in the area of the PCM driver and/or injector.
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Jesse Berger 90 LX, Previous 4 cyl. (Decommissioned, 351W on the way)
H/C/I+Bolt Ons
Best ET: 12.54@106 mph 2001 V6 5 Speed Daily Driver Windstar Intake, Dual Exhuast, CAI, Headers
Best ET: 15.6@88 mph (stock trim)
well if replacing the pcm which you suspected had a burned out injector driver.. then it was fixed but then seemed to burn out again.. maybe its something about the wiring with your injectors that is burning out the injector driver if thats possible..
stalkerstang.. is that possible?
I just found that my 6th cylinder is pissing fuel when i turn the key on. when i remove the driver, my fuel pressure gauge stabilizes at 40 lbs.
When i plug the wire for 6 in, i hear it washing down the walls and the gauge drops to around 20lbs.
The values on resistance at 2K range are 4.30 for all the drivers with the exception of cylinder 6, which is 13(this is with the key off).
Each of the drivers (with my meter on 20 VDC ) reads 0 with key off. With the key on, a constant 12 VDC is measured at the pins for the number 6 injector.
Is there another component between the connector for the injectors and the multi-pin connection on the PCM? Or is it a straight plug to plug within the loom?
There is a large multi-pin connector on the fire wall at the passenger side. Is this a possible source of the incorrect voltage im seeing at Cylinder 6?
in another note, i did take the driver wire from 6, and put it on 5. i put 5 on 6 as well to confirm that the failure was wiring, and not the injector. Both injectors behaved the same with a good (cylinder 5 wire) and bad (cylinder 6 wire).
In another words, i can get cylinder 5 to piss gas using cylinder 6 injector's wire. I can get 6's injector to maintain fuel pressure when connected to cylinder 5's wire.
The wirring will go to a spot on the firewall from the PCM, then out to the injectors through the main harness...
Make sure to check all your voltage readings with the system "in tact" meaning do not disconnect things to check voltages, or your readings will not be correct.
If you want to check a wire, say between connector A to connector B, you need to back probe the wire with a paper clip or something smilar, leaving it plugged in. Essentially you will be doing a voltage drop. If the voltage drop between two connectors is high then you may have some corrosion or other issue in the wirring.
__________________
Jesse Berger 90 LX, Previous 4 cyl. (Decommissioned, 351W on the way)
H/C/I+Bolt Ons
Best ET: 12.54@106 mph 2001 V6 5 Speed Daily Driver Windstar Intake, Dual Exhuast, CAI, Headers
Best ET: 15.6@88 mph (stock trim)
I got out my fuel pressure gauge again. I then screwed it to the fuel rail. As i turned the battery on, I got pressure around 30-32lbs with the 6th injector wire unplugged. I then plugged the wire back into the 6th injector. I turned the car battery back on and heard fuel pissing with no pressure this time. I swapped my new PCM out after, and took my original PCM and plugged it in, thinking my PCM could still be the problem. That wasnt it.
This is a lot of fun. you guys have to be here! haha
Need to check the wirring between the PCM and injector. I'm thinking you have a high resistance somewhere, could be in the form of corrosion, damaged, bad connection, etc.
The higher resistance (& heat) could be causing that transistor in the PCM to fry.
__________________
Jesse Berger 90 LX, Previous 4 cyl. (Decommissioned, 351W on the way)
H/C/I+Bolt Ons
Best ET: 12.54@106 mph 2001 V6 5 Speed Daily Driver Windstar Intake, Dual Exhuast, CAI, Headers
Best ET: 15.6@88 mph (stock trim)
New Remanufactured PCM? not the problem i thought it was? 
