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Rough Idle, Loss power, Backfire

Discussion in 'Mondial' started by soucorp, Apr 18, 2012.

  1. PT 328

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    I agree after hearing the video clip. It almost sounds like you are running on one bank. As Steve has suggested check your battery voltage with car off and when on per his instructions. I would check the battery connections to make sure they are clean and tight before running any voltage tests.

    If the battery tests and the alternator output is sufficient I would check your plug extenders again for any pinhole burn marks.
     
  2. PT 328

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    You should be seeing voltage around 12.5 with the car off and 14+ with the car running.
     
  3. Ricambi America

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  4. Steve Magnusson

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    Set multimeter to measure DC voltage on something like 20V or 200V DC scale, connect positive voltmeter lead to positive battery terminal, connect negative voltmeter lead to negative battery terminal -- measure ;). With engine off = should be something like 12.3~12.6 V DC. When running ~1000 RPM should be at least 13V, running ~500 RPM is lowish and might drop the alternator voltage some, but what hit me as odd in your video was that "light went dim and then RPM dropped" rather than "RPM dropped and then light went dim" and "light went bright and then RPM increased" rather than "RPM increased and then light went bright".

    For the AC measurement, set the multimeter to something like the 2V AC volts scale. In any mode, this should never be more than something like 0.1~0.2 V AC -- so a big value here is bad.
     
  5. soucorp

    soucorp F1 Rookie

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    #80 soucorp, May 6, 2012
    Last edited by a moderator: Sep 7, 2017
    Ok, just took some readings with my INNOVA 3320 meter:

    set to DC
    ignition off, car battery measures: 12.67 dc
    ignition on good idle = 13.73 -13.75
    ignition on bad idle (dip) = 13.4 - 13.56

    ok, so not sure if I did the AC measurements correctly but this is what I have.

    set to ACV~
    readings: ignition off, battery = .001
    ignition on, battery = .016 - .019 good idle
    ignition on, battery = .021 - .026 (dip)
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  6. Steve Magnusson

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    You did that correctly, and can't fault any of those voltage results.

    (I, too, have not reread the whole thread, but) It certainly wouldn't hurt to follow Daniel's good advice, and confirm/deny if you have spark occurring on both banks during the normal idle RPM and during the dipped idle RPM (although, offhand, I don't see how that wouldn't explain the oddish behavior of the brake failure warning light brightness corresponding with the RPM change). It does seem from your photo that you might have dumped some oil on the TDC sensor connectors.

    If spark isn't the problem (and, hopefully, it is because that would be a lot easier to fix ;)), I don't have the 1988 US Mondial 3.2 wiring diagram book, but I do have the euro version. It indicates that the same relay that turns "on" the brake warning light also is involved in the ABS system. Does your car have ABS? If spark isn't the problem, can you detect any correlation between the ABS pump operation and the change in idle RPM?
     
  7. PT 328

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    Piggybacking Steve's thoughts...How long has the brake warning light been on? Have you checked to verify the brake fluid is at the correct level? Typically you would see some flickering/flashing of the warning light which indicates codes. Since yours appears to constantly lit I would check the fluid level first.

    It is driving me nuts to see you throwing new parts at the car and not finding a resolution. I can't imagine how you feel. On the bright side when this is over you will have a near new car. :)

    If you want to discuss this over the phone PM me and I will give you my number. I have already completed my yard chores for the weekend.
     
  8. soucorp

    soucorp F1 Rookie

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    Thanks Dan and Steve. Its abit frustrating and I really thought it could have been the O2 that was bad but not. btw Steve, what is the TDC sensor, Im thinking it does have some correlation to the oil leaks? The ABS brake light is due to low brake oil from me doing a clutch slave at the moment. I dont think that is the prob, as soon as I add fluid, the light goes out. I will clean out the battery connections as well, but need to put on a new slave later today. The idle problem was there before I put in new sparks, stay tuned, thanks.
     
  9. Steve Magnusson

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    #84 Steve Magnusson, May 6, 2012
    Last edited by a moderator: Sep 7, 2017
    They are two of the three "crank sensors" used on your model that Daniel mentioned (although they actually sense physical features on the flywheel) - one for each bank (so when one TDC sensor fails, that corresponding bank's ignition fails -- if the RPM/Tach sensor fails, both banks' ignition are lost).
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  10. jgoodman

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    Steve, do you have a close-up of the TDC sensors and their position relative to the flywheel? What are they sensing off the flywheel? A magnet? Do you have a pic of it? I'm very curious as to what left me stuck in Quarryville, PA a few years ago, during Zaff's Miglia Mille, in the middle of Amish cow country. It was me, my wife and my dead-in-the-water Mondial with a broken TDC sensor off the flywheel.
     
  11. soucorp

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    #86 soucorp, May 6, 2012
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    Thanks Steve,
    I notice there is some oil around the sender unit, I changed that 6 months ago, but prob did not tighten it as hard as I can. Will check that, but it could be that the oil may have gotten to and contaminated the TDC sensor as you mention in the picture. I will try to unhook it and clean it with contact cleaner if there is oil on the contacts. Where does the other end go to, inside the flywheel?
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  12. Steve Magnusson

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    #87 Steve Magnusson, May 6, 2012
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    The two TDC sensors "sense" the passing of two pins in the flywheel face mounted 180 degs apart (labeled "1" in this figure -- the offset section A-A detail in the lower left corner shows the distance from the end of the tdc sensor to the body of the pin and how much the pins protrude above the flywheel surface). The RPM/Tach sensor (called "tachimetrico" in the figure) "senses" the passing teeth on the ring gear:
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    Some pics previously posted by others --

    The 1-4 TDC sensor mounted on the engine:
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    The 1-4 TDC sensor itself:
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    Some comparison shots showing the stock 5-8 TDC Sensor (Marelli SEN8F) vs a more readily available Marelli SEN 8D sensor for some other auto (the metal mounting plate is a little different so you can see how the OP had to open up the holes in the mounting plate in tha last photo to use the SEN 8D sensor as a substitute):
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  13. soucorp

    soucorp F1 Rookie

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    #88 soucorp, May 6, 2012
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    I checked the battery terminals and did noticed the positive side was almost welded to the cable and they looked alil beat up. So I will clean it and make sure there are no loose grounds.
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  14. N_Hornblower

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    I managed to get a kit for my pump...

    ...but then I got a new pump because I ran out of time on the rebuild. I had a road rally to join!

    If anyone wants a gently used WP + rebuild kit from an 88 Mondi 3.2, send me a PM. I'll make you a deal you can't resist!
     
  15. soucorp

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    #90 soucorp, May 11, 2012
    Last edited by a moderator: Sep 7, 2017
    So today, I started to do more troubleshooting on my idle ignition problem. BTW, never touch the coils with a running engine, I will only touch it with the battery disconnected.

    It lead me to looking at the coil assembly units. I notice the first coil was loose compared to the second one. so I unbolted the screws and examined everything. Noticed the rubber cover was also torn but the wire connections were tight and good. I'm hoping this is the source of my idle problems if the ground was loose. But will tighten and put it all back tomorrow and test the car again.

    Another possibility would be the TDC sensor to the flywheel, I see oil on both ends of the wire that may have contaminated the function of the sensor.
    I 'll clean it tomorrow and see what happens.
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  16. PT 328

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    Are the connections at the bottom of the coils clean and tight as well? I am sure you have checked them but I thought I would ask anyway. Crossing my fingers the cleaning solves your problem.
     
  17. soucorp

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    Thanks Dan, I will clean all of the contacts with contact cleaner spray and put them all back tightly and see what happens. Fingers crossed!
     
  18. soucorp

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    #93 soucorp, May 12, 2012
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    Today I continued my troubleshooting and installed the new clutch slave cylinder.
    I tighten and clean all of the connections with coils, TDC sensors, battery terminals and ground connections. Thought this is my day right??? Not !

    I started the car, still misfiring and bad idling. So I got a new timing light I bought online, best time saving tool ever, -plugged it on the spark plug wires starting with engine rear facing first. All timing was good on all 4 wires, correct even on the dips. So I went to the other bank of cylinders behind the rear seats, and BINGO! Intermittent firing on all wires starting right to left. So, I'm thinking it points to bad coils maybe. My next task is to swap the coils to see if the problem has reverse banks. What else should I try ?

    video of misfiring on one bank.
    [ame]http://www.youtube.com/watch?v=ZBoM-aww2pg[/ame]
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  19. PT 328

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    Swapping coils is all you should need to try. It appears you have found the problem.
     
  20. soucorp

    soucorp F1 Rookie

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    I hope that's the problem Dan. Thanks for your guidance. I think I'm close to solving the mystery, but this car has been eating up all of my family time and wifey is not happy! :(
    But I just tell her that I'm saving thousands doing this myself and that's extra shopping money! :)
     
  21. PT 328

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    It seems like your wife and my wife are long lost sisters. :) She gave me some heat this morning for changing out a thermostat on my neighbors father's car.

    At least it was quiet in the garage.
     
  22. jgoodman

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    Good news. I read somewhere on here that that little black thing on top of the coil is what often has the problem. Obviously your rear bank coil still makes a spark, albeit inconsistently. Maybe the whole thing won't have to be replaced. I may have an extra one for you to try to see if that fixes it.
     
  23. soucorp

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    #98 soucorp, May 12, 2012
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    Hi Jay, I'll try changing the top coil module first. If its that, its way cheaper to fix.
    New Ignition Coil Electronic Module For The 3.2 Mondial = $139

    If its the whole coil unit, that's expensive.
    New Ignition Coil For The Ferrari 3.2 Mondial 1986-88 = $439

    Let you know my findings tomorrow. If its neither of these, could be bad cables going into it.
    Thanks.
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  24. Dizengoff

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    Here's hoping that the problem is almost solved! It can really be frustrating to troubleshoot this kind of thing.

    I found that when I have to spend a lot of time working on my car that it's always nice to take my wife out to dinner or a weekend at a B&B. It really helps smooth things over :).
     
  25. PT 328

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    Mike,

    I will do you a favor. :) Call these guys and ask for part number XM631 made by WAI. In the past they have stocked the ignition module for I believe around $20 if my memory serves me correctly.

    Houston Warehouse
    9225 Manchester St.
    Houston, TX 77012
    Tool Free: 800-392-3332
    Fax: 713-928-3219
     

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