Misfire with AC on | Page 3 | Ford Escort Owners Association (FEOA)
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Misfire with AC on

Discussion in 'ZX2 1998-2004 2.0L DOHC' started by RonW, Oct 17, 2020.

  1. Apex

    Apex FEOA Member

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    Throttle position would also be a helpful PID to have in addition to RPM, we can probably take closed loop out now.
  2. RonW

    RonW FEOA Member

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    That I can do. I'll get to the laptop tonight and see what I can do with it
  3. Apex

    Apex FEOA Member

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    Check mode 6 under FORScan as well, like I said there should be cylinder misfire rates for each cylinder displayed as a percentage. Knowing whether this is a single cylinder, 2 cylinders, or all 4 cylinders misfiring will give us direction on where to go.
  4. RonW

    RonW FEOA Member

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    Okay, hopefully on the laptop that is doable. It is not capable on the mobile app
  5. RonW

    RonW FEOA Member

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    So I'm about to start working on the laptop. Two things, tomorrow I'll have the snap-on scanner back so I'll be hooking that up as well.

    Possibly better is the overheating issue may be gone. I won't say that it's positive yet, however on todays ride home I was stopped in the same traffic as usual, where the ECT would shoot up to 210+ and it only went to 187 and then dropped back down below 180. It did the same in 3 situations, so it might just be resolved.

    For the record I used Thermocure as directed but after a 24 HR cycle of driving I let it sit all weekend. I then hooked the hose into the backflush adapter I installed and flushed for about 25 mins, 15 engine running.

    Fingers crossed on that. It still has the sputter/misfire when taking off from a light. Again describing it like it's loading up with fuel while idling and is trying to burn it and additional fuel on take off from light. Could be a lack of fuel? Or injectors? Anyway that's the now.
    Thanks again for all the help
  6. Apex

    Apex FEOA Member

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    Hopefully we can figure that out once you have more data! Can't really diagnose based on symptoms.
  7. RonW

    RonW FEOA Member

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    I'm gonna call the overheating issue fixed at this point. Temp still rises but at a much more reasonable time frame and only after sitting at a light for a long time. The low fan kicks in as its supposed to but it never got that high driving home.

    I had no luck with the laptop, however I do have the snap-on scanner and while investigating today I found nothing, as in zero for misfire. Watching the individual cylinders and all was fine. Going thru $06 data all cylinders reported no misfire as it sat at idle for 30 mins or when driving around.
    So what I did notice is the fuel pressure and hovering around 31, the tool says 33-50 or something close to that. I also noticed the trims were out of wack but it is still in learning mode. So with the scanner I saw and read more about the procedure for resetting the KAM and PCM and I did run them to clear everything and start the learning process again.
    Side note: My ABS, yes this car has it has constantly been throwing codes of all types. As such I never replaced anything because basically it said it needed just about everything. In the scanner there is an abs function that "bleeds" the brakes. Basically it spins up the pump and pushes everything around, and just like that all my codes are gone. I would always clear them and they'd come back one by one on the ride home.
    I have the scanner, anything that you think would help I can do.
    Thanks again for helping
  8. Apex

    Apex FEOA Member

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    31 is a bit out of spec, but does it at least maintain 31 when you rev it up, or does it drop? If it drops that would be indicative of a regulator issue. Could be the fuel pump is starting to get weak, but I wouldn't immediately condemn it without doing a few more tests. For example a voltage drop test to the fuel pump, if it's not getting enough voltage that could definitely be an issue, or if it does not have a good ground.
  9. RonW

    RonW FEOA Member

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    Great idea, I didn't notice any drop at all. I will check the voltage tomorrow morning and ground if I'm able? I'm unsure how to check the ground.
  10. Apex

    Apex FEOA Member

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    Did you check the voltage under load? Checking voltage drop without load is meaningless.
  11. RonW

    RonW FEOA Member

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    20201028_161639.jpg 20201028_161639.jpg 20201028_161839.jpg

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  12. RonW

    RonW FEOA Member

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    I did get the laptop working, I'm not sure how to actually get the live data to a file to upload. I tried recording on my phone but it won't upload, I guess because it's. Mp4 file. It is still in learning mode, but the trims are definitely not good at idle. Idle is good and at 750-760 rpm
  13. Apex

    Apex FEOA Member

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    The oscilloscope tab at the top will show data over time.

    Take out some of those extra PIDs, keep FRP in psi, LTFT, STFT, Load %, IAT in degrees F, then add MAF and RPM. Click on the tab at the top that says oscilloscope, then do some free revving in neutral take a picture of that, then do some driving around to put the engine under more load and take a picture of that as well.
  14. RonW

    RonW FEOA Member

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    Okay, I'll do that. Should I wait until the p1000 is done?
  15. Apex

    Apex FEOA Member

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    I don't think that should matter too much if at all.
  16. RonW

    RonW FEOA Member

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    So I was away for the weekend and didn't have my laptop. In the meantime I received a car charger for it to allow better usage going forward.

    New info - I decided to have a look at the spark plugs as I never really checked them since this started. They were new, but that doesn't always mean much. Pulled off the first boot and loaded with oil on the outside, second, same thing, as you probably guessed all were filled with oil. The new Valve cover gasket was leaking into the area and would never have known. Pulled the cover off, had a new gasket so I replaced it, the gasket itself was fine, the grommets were just not doing there job. It was a Victor Reinz gasket and I assumed of better quality than the one I had from a local auto parts store. Lesson learned, the grommets in the Reinz were much thinner and just squashed down to nothing.

    Cleaned up the boots and let them dry, cleaned out the spark plug bay and installed new plugs and so far seems to be running right, haven't noticed the phantom random misfire. Maybe oil was causing some grounding?

    Thoughts?
  17. RonW

    RonW FEOA Member

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  18. RonW

    RonW FEOA Member

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  19. Apex

    Apex FEOA Member

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    The short term fuel trim seems pretty bouncy, although that's not totally unexpected. What I need to do is see if I can correlate this data to my own ZX2.

    I assume this data is after your spark plug well fix? The numbers look more or less ok in most instances from what I can tell (+/-5% on LTFT and STFT is good). This is not quite what I was expecting based off of your previous experiences, and we never at any point hit 30% on either STFT and LTFT so clearly there is an improvement already, unless the same conditions were not occurring from the previous test to now?

    Can you confirm that the total fuel trim (STFT+LTFT) was only about +10-12 at the worst points? It looks like at the highest points of vacuum were also the leanest points, but at idle the fuel trim looked good. The one thing that looks a little weird to me is the erratic measurements of load and MAF at some points, though maybe this is clutch engagement?

    If you want to collect some more data, could you fullscreen FORScan so you can have more PIDs and they are easier to read? There should be some scaling options as far as I know as well to make the display easier to read. It was a bit hard to decipher what each PID was on the graph, but I did figure it out. It would also be good if you could screen capture directly from the laptop instead of taking it with your phone camera, there's dozens of good applications you can grab off the internet for this. Dropbox, Gyazo, etc. Or natively on windows you can just printscreen and paste into MS Paint.

    One more PID that would be good to add is TPS. I'm pretty sure TPS and MAF measurements should directly correlate, so anything that looks weird comparing those two should give us some direction if there's any issue there.

    Having spark plug wells could certainly cause a short to ground prior to the electrode of the spark plug. That's most likely the cause of your misfires.

    When you cleaned the injectors, how did you do this? If you removed the injectors, did you replace the o-rings and grease them up when you did so, so that they popped in nicely?

    Also, one thing I noticed is that your RPM reading looks really low, are you really idling at less than 500 RPM?
  20. RonW

    RonW FEOA Member

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    I'm going to make the adjustment to screen and will answer the questions better when I get some time.

    In the short, yes this is after the oil in the plugs find and repair, and yes the car is much much better than it was. Seems pretty close to what it was before all hell broke loose. My helper did the actual cleaning of the injectors, new screens and seals. I did not look at them but he is experienced mechanic. One issue that has improved but I still feel is incorrect is the load %? I feel it is still to high based on the circumstances. I don't know what controls that reading? It just seems to be high when it is not under much strain, it is better as it would jump into the 90's for any acceleration, but it's still higher than I feel it should be. If you have any input on where to address that would be great. Thank you

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