New issues have me stumped??

Discussion in '94-95 5.0 - Specific' started by ElrodKTPQ_89, Sep 22, 2014.

  1. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    So a few weeks ago we tore my engine down for my roller rocker and cobra intake swap. Everything had been going great, the car was running perfectly. A week ago on Saturday I drove about 30 miles outta town and everything was fine on the way there. When I was about to head back home I pulled into a parking lot and ran over a pothole and jarred the car pretty good. As I left the parking lot the car all of a sudden had a dead miss. So I drove to a friends house close by and found that I had burnt the plug wire on #5 cylinder against the header and thought easy fix just go grab a plug wire from his shop....well we did and that didn't change a thing. I drove the car back home and just gave up on it for the day. One day during the week I decided I would fire it up and see what happens and to my surprise it idled and drove fine...until the temp gauge moved up into the normal operating range then all hell broke loose and the misfire starts again. The same thing happened last night, I drove it about 2 miles from home and then it started acting up once it warmed up. Anyone have any ideas?? It's pretty aggravating and confusing since it was running so perfectly until I hit a pothole. I haven't found anything unplugged or any loose connection anywhere but I haven't checked all of the grounds just yet and I'm not really sure where else to look.
     
  2. laserred95

    laserred95 New Member

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    Did you try changing the plug itself?
     
  3. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    I did not. I checked the plugs though and they looked fine. I wasn't really suspecting it to be the plug though since it only starts missing once it's warm.
     
  4. RichV

    RichV Well-Known Member

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    Well you can unplug each wire when it's missing and the one that don't change engine tone is the miss.

    If it's ignition related. Who knows if its due to the bump or something coincidental.
     
  5. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Sorry I forgot to mention that we did that. The miss was coming from #1 cylinder. So we changed that plug wire also and checked the spark plug but everything seemed to be ok.
     
  6. RichV

    RichV Well-Known Member

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    Did you check the distributor cap tower?
     
  7. laserred95

    laserred95 New Member

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    i would change it out for good measure if not compression check as well. long shot but maybe injector.
     
  8. D3VST8R96GT

    D3VST8R96GT Well-Known Member

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    Use a timing light to see if the signal is coming from the distributor to the wire..... if you get a signal id check the injector and do a compression check
    all new plugs never hurt.
     
  9. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Still haven't checked my injectors or done a compression test, I haven't had much time or energy to mess with it (work & family blah blah). I did change plug wires to some good Ford Racing 9mm wires and changed plugs Sunday and still not any better. Also it's no longer starting once it gets warmed up...now it's almost instant as soon as the car fires up.
     
  10. CC'S95GT

    CC'S95GT Legend

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    I thinking it's a sensor since it's fine when cold (open loop) then starts missing when warm (closed loop)
    MAF, O2 sensor, inlet temp sensor etc.
    Did you pull codes? do a KOEO and KOER.
     
  11. mcglsr2

    mcglsr2 Well-Known Member SN95 Supporter

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    Are you sure it's still missing on #1, or is it just running like poop when warm? If it's the latter, I'm going in with CC'S95GT on this and saying it's a sensor - maybe you knocked an O2 sensor loose or something.
     
  12. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    havent checked codes yet either, I've really been kinda lazy with it lol. But that's kind of what I was thinking too that it might be a sensor due to the way it acts when it's in closed loop. A friend offered that it might be a ground issue but I'm not really convinced of that just yet.
    I had been thinking that an O2 sensor may be a possibility also but the car is so damn low I can barely get under it to check and I don't have a jack at home at the moment. Besides the MAF that I'm using that came with the cobra intake EVERY sensor on the car is new. And also I don't think it's just #1 this time around...it just runs like crap period. And to correct myself one o2 sensor is new and one is original so I will check into that this evening when I get home it hasn't really crossed my mind until now.
     
  13. CC'S95GT

    CC'S95GT Legend

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    Ck the electrical connector to the coil too.
     
  14. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    Connections on everything were good. A friend of mine let me borrow a set of Noid lights last night. We started off firing the car up and pulled the #1 plug wire off the cap and there was no change in the tone of the motor. The plug has fire to it though. Put the light on #1 injector and it has fire to it also. So we are thinking maybe just a bad injector. Tomorrow we are gonna swap two of the injectors around and see if that changes anything.
     
  15. mcglsr2

    mcglsr2 Well-Known Member SN95 Supporter

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    If the injector were bad, I'm not sure the car would be fine when cold, and then not fine when warm. In fact, wouldn't the issue be worse when cold, since the injectors ignore O2 feedback and basically spray a lot of fuel to overcome the coldness of the engine? If one of the injectors was bad, you'd have a rough start I would think. Unless the injector was fine at a low duty cycle but then had an issue at a higher duty cycle (2000 rpms or more, or whatever). I have a hard time seeing how an injector could fail like this - but I haven't seen it all, so it's totally possible.

    If the issue really is apparent when warm (closed loop), then issue is in some part of the feedback loop. Which is typically O2. Though I supposed there could be a timing issue as well, since the car does move to different tables (IIRC) when operating in closed loop vs open loop.
     
  16. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    [MENTION=15705]mcglsr2[/MENTION] I don't know if I mentioned it or if you missed it above but now it has started off missing as soon as it starts up. Still haven't pulled codes though so I'm not really getting anywhere til I do so I guess I need to try that tomorrow.
     
  17. mcglsr2

    mcglsr2 Well-Known Member SN95 Supporter

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    Oops my bad, I probably missed it. Okay then, that sounds like it could be an injector. Do you think it's related to how it was missing before when it was warm?
     
  18. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    At this point I'm really not even sure. This car has acted so crazy before it really makes me wonder if any of these issues are related to each other. It makes me wonder if there is any significance of the miss coming from #1 cylinder though. Even though the distributor is brand new less than 1000 miles on it I kinda wonder if it may be caused by it still. I left this out of the post above but check this junk out....while we were working on it last night we started going over the possibilities of what could be causing it and said let's take the cap off the dizzy and look at everything inside. So we take the cap off and pulled the rotor off and pulled the reluctor wheel out cuz he wanted to just check to make sure it wasn't bent or anything crazy like that. Nothing seemed outta place so we put everything back together and fired the car up and it ran pretty smooth for about 45 seconds-a minute. Then my buddy put the car in drive and tried to load it up a bit (1100-1300 rpms or so) and then it started to miss again. Makes absolutely no sense.
     
  19. mcglsr2

    mcglsr2 Well-Known Member SN95 Supporter

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    Damn that's weird. Not a clogged cat, is it? Just thinking out loud now...
     
  20. ElrodKTPQ_89

    ElrodKTPQ_89 Legend

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    No cats. Lol. I thought about changing out the old o2 sensor just to finally rule it out but I hate just throwing money at this thing without being certain that's what it needs ya know.