Car is flooding and scanner won't communicate with computer WTF

Discussion in '94-95 5.0 - Specific' started by ElrodKTPQ_89, May 16, 2015.

  1. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Copied this statement over from my build thread:

    On to the other issue...at first it pissed me off and I didn't even work on it for about a week. Then did the belt, then a week off, and now it's back to working on the car. To start off I pulled the air box and intake tube all out, cleaned my filter and my maf, and checked for any unplugged or loose connections or burnt wires....nothing. I even tried to hook my pocket code scanner I keep in the car up to see what it would show and after several minutes of waiting it never pulled up the first code which is unusual so I gave up. A few days ago my friend brought over a Snap-on diagnostic tool of his, and guess what, the computer wouldn't communicate with it either. So we decided to pull a plug out of each side just to check them, both were black. I had an extra set of plugs so we went ahead and changed them all out, and all 8 were black. And when we fired the car back up the condition had stayed the same...it was dumping fuel for some reason we cannot figure out.


    After that the scanner finally retrieved a code for the o2 sensors (code 42). Well the car had one original sensor and one new sensor, and since I had a little store credit at the O I went ahead and picked up another sensor. Swapped it out the next day, fired the car up and bam it ran almost perfectly except that it idled at 1200 rpm. So my friend came back over after that and we fired it up, it continued idling high like that for about two minutes then just died. Upon firing it back up it went back to running just as it had before. So yea, we're still stumped. My next attempt was gonna be to clean the throttle body and iac and see if that helps. I'll probably be doing that this evening.



    since then I have cleaned the throttle body and IAC. Just fired the car back up today and still the same shit. No clue why it's doing this. I've been tempted to take my temp sensors back to O Reilly's and swap them out under warranty just to rule them out. I'm losing my f&@*ing mind working on this thing.
     
  2. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    [​IMG]

    [​IMG]
     
  3. JKady

    JKady Active Member

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    That's a throttle position sensor code, not an o2 code. The TPS being misadjusted or bad could definitely cause your runability issue. That second scanner you posted a pic of has the capability to be used as a lab scope, I would hook it into the back of the TPS connector and check your voltage with no thottle input and then take a look at the sweep from idle position to full throttle (key on engine off) and see if it's dropping out or spiking anywhere. They're a very common failure on EEC-IV systems. The computer itself is also an extremely common failure point, they like to break/burn and/or short internally
     
  4. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    I noticed after I posted that that it was a TPS code, just didn't go back and correct myself. It did throw a code for the o2 sensor also though. I have a 5 speed computer, have thought about swapping them out to rule it out also.
     
  5. JKady

    JKady Active Member

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    At the age of these EEC-IV systems computers are really starting to show their age. My car's got some issues that are making me lean toward it, my truck ('90 F350) definitely has an internal problem. Sometimes they will do some REALLY weird stuff when the EEC starts to give up. I fixed an E250 with a misfire a couple weeks ago that had shorted internally between the ignition and the transmission sections inside the computer, you could unplug the trans harness and it would stop misfiring.
     
  6. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Tried again today, this time with a Snap-On Vantage graphing meter, which allows you to test each sensor individually. We checked the ECT, MAF, and TPS and everything was within the range it was supposed to be in at normal operating temperature. We also checked the OBD-1 port on the strut tower. According to the info on the vantage, pin #4 should read 12 volts KOEO, however it barely read 1 volt, all others were in their normal range....could this be why none of the other diagnostic scanners we've used won't communicate with the computer? My friend that has been helping me work on it also wanted me to ask if the fan was supposed to come on when the key is on....with the key on, the fan automatically comes on as well as the fuel pump and both run wide open. We wound up unplugging the fan and pulling the fuse for the fuel pump while running the test on all the sensors to keep from running the battery down. Doesn't that have something to do with the CCRM possibly being bad? As it stands right now we prolly won't be able to try anything else til Thursday. Next thing I'm thinking of trying is swapping the computer out with my 5 speed computer.
     
  7. JKady

    JKady Active Member

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    The fan should only come on when the engine is hot, fuel pump should come on and run for a couple seconds then stop with the key. Sounds like you may have a CCRM issue. And yeah, if the pins on the EEC test plug aren't reading right that definitely could be your communication issue. I would definitely pop the other computer in and see, you've got multiple odd issues going on at once.
     
  8. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Can the relays be replaced themselves or does the whole CCRM have to be replaced if there is an issue with it?
     
  9. RichV

    RichV Well-Known Member

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    It's a module. You replace the whole thing, you may be able to break the seal and test individual circuits, but you're just making life harder. Tim Palcovich (?sp) has a bunch on the FB Parts Page.

    I would probably see if you can borrow one before buying a replacement, just for testing.
     
  10. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Thanks for the info bud! And yea I know the guy, I think his name on here is full force.
     
  11. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    Definitely try that other computer you have. It wont take long to plug the new one in, just to make sure that is (or isn't) your problem.
     
  12. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    If it wasn't such a mother****** to get to lol. I'm really tall, my car is really low and it's in a bad spot. From what I could tell it looked like there was only one screw holding it in on the bottom left corner, is that it? Besides the harness connector of course.
     
  13. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    You have the one screw you can see and then I think there is one at the top across from the other screw. Then that little plastic retainer will unbolt and the computer comes down with it.
     
  14. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Exactly what I was afraid of lol
     
  15. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    Its not that bad with a small 1/4" ratchet. I don't think you can see it, you will have to go by feel. However, I think that there is a way to unclip that plastic piece. I'm going to go out to my car and confirm that. I will report back.
     
  16. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    ok, it looks like you might be able to unbolt the bottom bolt and bend the plastic out of the way to slide the computer out. I don't know for sure if it will work because mine is already apart and I pulled my dash first so it was easy lol.
     
  17. rz5.0

    rz5.0 Legend

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    Should just be one bolt. . I want to say i unplugged the harness first
     
  18. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Finally got it today, lol. Thanks a ton guys. Swapped the computers and fired it up and it runs perfect just like before! Never expected it to be that easy lol. Kind of wish I hadn't been so lazy with it and done it sooner but it's all good. Now it's more ready than ever for the T5!
     
  19. JKady

    JKady Active Member

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    Already having the computer in seems like all the justification one would need to me... I mean hell I'm about to give mine a heart transplant over a leaking timing cover.
     
  20. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Lol I heard that! I have everything I need waiting in the shop so I hope I may be able to start on it this weekend.