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Thread: 1990 Mighty Max v4 2.4L, Starts and Immediately stalls

  1. #1

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    I.D.K.?

    1990 Mighty Max v4 2.4L, Starts and Immediately stalls

    Hello everyone! I am a new member, but been an observer for quite some time! I bought this truck in jan 2014, and everything was fine until one spring morning in april 2014. I went to 7-11 for my weekend coffee. Once I got back into the truck it would turn over but not start. fuel pump was bad, took it to a local shop fixed it and replaced fuel filter.. Everything was fine for a couple weeks until it would randomly stall on me while driving a real clean cut too. Go to restart the truck turns on then stalls. I would repeat this process frantically until it would run and drive. Some of my friends were telling me "hey its just some moister in your fuel lines etc. you'll be fine".. I believed them because weeks would go by, and I would have no issues starting or running the truck around town.. however unsuspecting the truck would stall on me while going 45 mph, and would not notice until I had no power and seen my dash would be lit up with all the lights.. The truck would restart, but then again stall immediately. You could repeat this process 100 times, and it would do the same thing. Start as if it were going to catch, and then stall. Sadly this time a tow truck had to carry my mighty max off the road. Onward to the shop the guys so confident that its the fuel pump/filter again I paid 300 dollars and let him replace it. Only to have to same issues so I have it towed home. So now its in my drive way starting and stoping. Some cranks it will run and Idle for as long as I want, but will return to the same the next day.. Any ideas for I lose hope on my truck. One thing I should note, after the first fuel pump/filter replacement I started getting pinging like a pre ignition knock sound when I would be going a consistent speed.

    Things I have replaced::
    Plug wires/cap/plugs
    alternator/when bought it had the original from 1990
    Gas cap
    radiator cap

  2. #2

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    Pop open the ECU and take a whiff.

  3. #3

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    I.D.K.?
    no kidding

  4. #4

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    No, I'm serious. The ECUs on the 6 bolt 2.4s are notorious for blowing out capacitors. They bulge and leak and the PCB will smell sharp and tangy. Bad ECU can also cause the symptoms you're describing.

  5. #5

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    I'm going to go take a look at it right now, I'm suspecting the worst.. I've done a lot of research I didn't post because the thread would of been as large as the windows xp code...

  6. #6



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    $300 and it wasn't fixed? uhhh, you may also want to ask for some money back from that guy, lol. Check out what Noah said on the box. We have had some issues in the forum about them problems. Sounds like a computer issue to me also, could be a solder weld broken or blown capacitor, look for burnt (carbon) remnants on the board.

  7. #7

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    I cannot seem to find the damn thing, and google is not helping! Any lead where I can find the ECM

  8. #8

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    Passenger side kick panel, there are relays, look for the yellow plugs above them.

    Brad, my stepbrother spent a year and hundreds of dollars on his '92 going in and out of the shop trying to get it because of almost identical problems in the OP. The mechanic had no idea what the problem was and gave up. Finally Sean gave up on it too and sold me the truck for $300 because I had been pestering him about it since the Clinton administration. Guess what the problem was?

  9. #9



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    Was your stepbrother upset after you told him you fixed the truck?

  10. #10

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    No, he was happy the truck was back on the road.

  11. #11

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    I found it removed everything in the way, removed the two 10mm bolts tried to slide it out. well its bigger then I thought, so I guess I'm going to have to remove some of the passenger side dash to get clearer access.. I'll keep posted with pictures.. I would be extremely pleased if that's my problem, because I've been going insane for months.. Noah I guess you truly win in your case with the 92 xD

  12. #12

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    You shouldn't have to remove the dash. It's kind of a bitch getting the bracket that holds the ECU in place up over the lip on the pillar sheetmetal but it if you give it a lift towards you and then pull straight down (after all 3 plugs are unplugged), it should slide out eventually. Sometimes a few wiggles back and forth will help. Keep at it, it will give way.

  13. #13

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    yeah everything is unplugged, and pushed away.. I was fighting with it for a short while, but didn't want to get to aggressive.. Its been below freezing here so I'm going to wait for a warmer day to start tugging on things metal!

  14. #14

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    I cannot reply :{

  15. #15

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    I was tugging on it for a short while, until I damn near froze to death its been below freezing.. I will get back to it, and post some pictures!

  16. #16



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    Have you just tried taken the cover off it and using a flashlight to look at it?

  17. #17

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    its real tight in there, I got a blower in my way

  18. #18

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    wait, is there a way I can pull the ECM without taking out the whole bronze looking bracket?

  19. #19

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    Yes, like Noah stated, it's tight but it will twist down and out without removing the bracket. You're fortunate if your ECM has lasted this long without a rebuild. I have had both of my 4x4 ECMs repaired by Foreign Auto Computer in Zephyrhills, FL. You send in your unit and it'll be back in a few days.
    1990 MM 4x4 3.0
    1991 MM 4x4 3.0 Diamonte
    1994 MM 2wd (work in progress)

  20. #20

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    after I unplugged the 3 plugs from the ECM I took off the two 10mm bolts and tried pulling down, but the bracket is large and will not freely pull out.. I didn't know you could freely pull out the ECM without taking the bracket with it.. When I went to take the side kick panel off the screw was missing for the cover so I'm assuming someone else hands have been there so it may not be the original..

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