HELP: 83 qv trouble | FerrariChat

HELP: 83 qv trouble

Discussion in 'Mondial' started by Matthew 6:19, Mar 28, 2021.

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  1. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    Hello friends, looking for some advice on where to start: drove the beautiful 83qv to a restaurant to eat. Came out an hour later, won't start. Cranking just fine, but doesn't even try to start. What should I check? Spark? Fuel? Other things?

    Pretty much a newbie here but want to learn how to work on this beauty, so assume I have not much more than basic understanding and skills.

    Thanks in advance for advice, suggestions, etc.
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,038
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, Mar 28, 2021
    Last edited: Mar 28, 2021
    Yes, both ;). First thing you should learn to do is how to unplug the (bluish/greenish) safety switch on the airflow meter -- with this unplugged, you should hear the fuel pump run when you turn the key "on". If you do, then touch the frequency valve to confirm it is vibrating (it should always vibrate whenever the fuel pump is running). For spark, you can buy a very inexpensive "spark tester" that you can just touch to a spark plug wire to confirm/deny if spark is occurring during starter motor cranking.

    When you can answer these three questions:

    1. Does the fuel pump run with the safety switch unplugged and the key "on"? Yes/No
    2. Does the FV vibrate when the fuel pump is running? Yes/No
    3. Does spark occur during starter motor cranking? Yes/No

    You'll narrow down greatly where the trouble might be, and what next diagnostic thing to do make sense.
     
  3. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    thank you Steve. Ok.... where do I find the blue/greenish safety switch on the air flow meter? I guess I need to learn where the air flow meter is?? Also, where/what is the frequency valve? Sorry... like I said, I'm a newbie (but eager to learn). Thanks again!!

     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,038
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #4 Steve Magnusson, Mar 28, 2021
    Last edited: Mar 28, 2021
    Do you have the OM for your exact year/version Mondial QV? Do a search on "safety switch" posted by "Steve Magnusson" for threads with pictures.

    And please ignore my comments about the frequency valve -- not present on a 1983 QV (but the other items apply).
     
  5. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    thank you!

     
  6. Subito Grigio

    Subito Grigio Formula Junior

    Jun 2, 2009
    327
    Welcome Matthew,

    If you really want to learn about your car, and want to know about some similar experiences I urge you to search this Mondial section of FerrariChat. Several hours of reading about this topic await.

    Best Wishes, SG


    Sent from my iPhone using FerrariChat
     
  7. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    A real quick test would be to press the air vane down and spray some starting fluid into the intake. If the car starts and runs a bit, then you have a fuel system problem. If the car still won't start, you could possibly have no spark, or no compression. Although a fuel system problem is much more likely to cause that kind of symptom.
     
  8. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    Thank you!

     
  9. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    Yes, doing that as well. thank you!

     
  10. MauroV

    MauroV Karting

    Jun 24, 2013
    152
    Italy
    Full Name:
    Mauro
    For years my 1983 QV had an intermittent fault. It would always start up from home but after getting fuel, or eating at a restaurant it often wouldn't start up again. I broke down everywhere. Outside restaurants on special occasions, going shopping, first in line to board a car ferry at Dover. It was a nightmare. The car gets a lot attention already without breaking down in an embarrassing location. I got very well known by the local car transporter guys who would take the car to whichever mechanic I was using and, once it got there, it would always start up first time. So the mechanics never knew what was the fault. They would have a theory, change or service something: Fuse box, fuel distributor etc. I would take it home, full of hope, only for the same thing to happen.

    Eventually, I started using a more specialist garage, Autosport at Pistoia, about 80 miles from home and eventually I worked out that rather than bring the car to Pistoia I should bring the expert Ferrari mechanic to the car. With the car not working he diagnosed the fault quite quickly. Turned out it was an engine harness connecting some sensors, sorry but I don't know exactly which harness, but it was rotted and creating a short circuit. They made up a new harness and the car has started and run perfectly ever since.

    Before I got the car it had 14 other owners and I suspect most of them sold it because of this fault. So, the morale of the story, if the usual checks don't solve the problem and you unfortunately have an intermittent situation get a great mechanic, make sure he can experience the fault, check out the engine harnesses :)
     
  11. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    thank you!!!

     
  12. FamilyCar

    FamilyCar Formula Junior
    Rossa Subscribed

    Sep 26, 2007
    655
    Seattle, Wa
    Full Name:
    Peter Goodall
    I recommend looking at the wiring connection between the fuel pump and the main circuit board/fuse panel. Years ago my car had a similar issue, it was somewhat intermittent for a while but quickly because a drive stopping issue. The wiring to the pump had overheated at the connection and damaged it, causing it to short circuit. This is one of the long, white connectors on the passenger's side of the fuse panel, the lower one I think. (Note that I have a 3.2, so there may be differences) The damage was visible just by pulling it off and looking at the exterior, where the burn marks were coming through as brownish stains. I suggest this because it is very easy to do, and caused me a similar problem. Good luck!
     
    moysiuan likes this.
  13. theunissenguido

    theunissenguido Formula 3
    Owner Silver Subscribed

    Jan 21, 2004
    2,371
    Argent/Brasil
    Full Name:
    Guido
    Fuseboard at the right side vertical white plug : Fuel pump wire (P) number 7 counting from above. There are 2 wire light brown.

    Image Unavailable, Please Login
     
  14. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    thank you!!!

     
  15. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    ok, finally had some time to work on this. We have confirmed we have engine spark. We removed the blue safety switch on the air flow meter and with the key on, we are not hearing the fuel pump at all.

    We have checked the relays on the main board in the front trunk, and they appear to be ok.

    Making progress, but need some continued advice as to what to do next. THANK YOU EVERYONE!


     
  16. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,038
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #16 Steve Magnusson, May 2, 2021
    Last edited: May 2, 2021
    Please confirm what version 1983 Mondial QV you have -- US or euro? (I'll assume that it's a US version in the following comments. If you have a euro version, the relay letters "t" and "i" might be different, but the relay names should be the same or similar).

    I'll assume that you've checked the fuse for the fuel pump is OK (i.e., not blown) -- if you haven't, please do so.

    If OK, remove the fuel pump relay (it's relay t if a US version), and touch a jumper wire from the female metal terminal 30 in the relay socket to female metal terminal 87 in the relay socket like this:

    Image Unavailable, Please Login

    The fuel pump should run when the jumper is in place (even with the key "off"):

    A. If the fuel pump does run with the jumper in place, try a different ...113 relay in the fuel pump relay position and repeat the "unplug safety switch with key on" test. If the fuel pump runs, try starting. If the fuel pump doesn't run, try a different ...101 relay in the relay i, Fuel injection delivery pump starting relay position, and repeat the "unplug safety switch with key on" test. If the fuel pump runs, try starting. If the fuel pump runs with the jumper in place, but you still fail the "unplug safety switch with key on" test when using different relays t and i = we don't want to go there...

    B. If the fuel pump doesn't run with the jumper in place, unplug the single vertical w white connector on the RH side, and inspect the terminal fourth from the bottom (or 7th down from the top) with two P (beige) wires for burning/frazzling as Guido had suggested. If it seems OK (and the fuel pump doesn't run with the jumper in place) = bad sign for the fuel pump itself or the fuse-relay panel itself. If obviously burned/frazzled, that needs to be repaired.

    Chew on some of that and report the various results/status -- we'll go from there.
     
  17. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
  18. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    Yes, mine is a US model. Thanks.... will try this next day or so! Really, really appreciate the help!

     
  19. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
  20. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    Ok we replaced the fuel pump, and it did start. But now it’s running REALLY rough. (Wasn’t before having these issues).

    Things we have observed:
    -Won’t idle
    -Fuse for fuel pump is hot
    -Won’t start again (without spray) because no fuel pressure.

    Any help appreciated.




    Sent from my iPhone using FerrariChat
     
  21. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,038
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #21 Steve Magnusson, Jun 3, 2021
    Last edited: Jun 3, 2021
    This is a little bit normal because the nominal CIS fuel pump current is high -- especially for a new, "tight" pump (IME, a new pump might be ~11A while a well run-in pump is ~9A). The heating is due to having a small resistance between the prongs on the PCBA and the metal fuse terminal(s). Make sure the contact areas of the prongs on the PCBA and the fuse are clean and that the prongs have a tight grip on the fuse terminals.

    Don't follow you here (if the fuel pump runs there should be fuel pressure). If you unplug the safety switch and turn the key "on" = the fuel pump should run -- does it? Also, if you remove the fuel pump relay and install the 30-to-87 jumper in the socket, the fuel pump should run (even with the key "off") -- does it? Did you ever unplug and inspect the connections in the w white connector?

    A US version '83 V8 has virtually no electronics in the K-Jet without Lambda system so the diagnostic steps (once the fuel pump does run) is to measure the regulated supply pressure, the cold control pressure, and the warm control pressure.

    The only "electrical" thing to measure initially would be to unplug the cold start injector and measure the DC voltage between the two terminals in the harness connector during the first cold start attempt -- should go 9~10V DC for the first couple/few seconds of starter motor cranking and then go to 0V. Alternatively, if you connect a 12V light bulb between the two terminals in the cold start injector harness connector, it should illuminate for the first couple/few seconds of starter motor cranking during the first cold start attempt and then go out.
     
  22. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    So it restarts by spraying starting fluid ?

    You could possibly have a bad fuel accumulator. You can test this easily by removing the return line to the fuel tank. If fuel spills out there, the accumulator needs to be replaced.

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    Matthew 6:19 likes this.
  23. Matthew 6:19

    Matthew 6:19 Karting

    Dec 19, 2018
    156
    Ohio
    Full Name:
    Jamie
    Thanks Steve, we will check this in the next few days.

    Any thoughts on no idle? Will stay running by feathering the throttle, but won't simple idle; dies if we let it. Thanks again for all the input.


     
  24. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,038
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    On a K-Jet without Lambda, it almost certainly has to be related to something changed in A/F ratio -- e.g., regulated fuel pressure too low (maybe fuel pump not at full voltage/RPM) or control pressure(s) some changed value. "Pumping" the accelerator adds richness by the WUR lowering the control pressure when the intake manifold vacuum decreases.
     

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