Close



Page 1 of 2 12 LastLast
Results 1 to 25 of 30
  1. #1

    Default 85 Mustang will not start after it warms up or gets hot

    I have a stock 1985 Mustang GT. Just a had the carb rebuilt with a Holley trick kit. Put in plugs, wires, rotor, and also a new mini starter. The car starts up fine when cold. After it gets warm is when it starts to act funny. Once you kill the engine (if it doesn't die on its own) it will not turn back over. Once you let it set for 10-20 minutes it will fire up again. Any thoughts?
    Last edited by bwlsn13; 12-08-2019 at 02:44 PM.

  2. #2
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Location
    Grand Junction, CO/RR TX
    Posts
    14,206

    Default

    Most likely ignition related. On the TFI equipped cars it was not uncommon for the TFI module to overheat and cause a similar problem when they had some miles on them. Had the same issue with a 1984 Trans Am with the HEI setup. the ignition module inside the distributor would get hot and cause the engine to die and not restart until it had cooled down after 15 minutes or more.

    I would check out the ignition completely and look at the conditions of the current parts. The only other issue I had before similar to this was a fuel vapor lock issue again on the 1984 Trans Am because of the original routing of the fuel line. It would cause the fuel to boil in the line in stop and go traffic in Central Texas during the summer months. Finally sorted it out and changed the routing of the fuel line and insulated it. That fixed that problem. Good Luck!
    Last edited by wraithracing; 12-08-2019 at 10:11 AM. Reason: Spelling
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  3. #3

    Default

    Thank you for the help. I have suspected both scenarios. I think I will look into the ignition first hoping to find a simple solution. Maybe ignition switch in the column? Vapor lock has me wondering why would that occur with an all stock car. I will post any progress. Thanks again for the knowledge.

  4. #4
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Location
    Grand Junction, CO/RR TX
    Posts
    14,206

    Default

    If the ignition switch on the column is old, then I would recommend a replacement no matter the condition. They are notorious for failing at the most in opportune time.

    The vapor lock on our Trans Am was an all stock vehicle at the time too, so don't entirely rule that out. The use of ethanol mixed fuels today only make vapor lock a bigger issue on older carburetor vehicles in my experience. I still believe your issue is most likely ignition related such as the ignition module, coil, inside the distributor, but I mentioned the fuel issue as a something to consider. Good Luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  5. #5
    FEP Super Member xctasy's Avatar
    Join Date
    Jun 2012
    Location
    Dunedin 9011, New Zealand, South Pacific
    Posts
    3,961

    Default

    Most likely a HIC problem.

    Check the Hot Idle Compensator.

    It is a hot fuel handling device that leans out the fuel air ratio when heat soaks the engine, especially a problem with oxygenated fuels or when the A/C is on idling in heavy traffic. It may be leaning out the air fuel ratio after warm by adding too much emulsified air into the fuel supply.

    See

    http://vb.foureyedpride.com/showthre...pensator-Valve

  6. #6
    FEP Power Member Jerry peachuer's Avatar
    Join Date
    May 2014
    Location
    Royal oak Mi
    Posts
    1,447

    Default

    I think your experiencing a ground issue with ignition

    I was chasing hot start issue and turn out to be a ground

    Try to not touch too many things at one time to isolate if it was progress or added to the problem

    Use a good size wire and go to your negative post to a "clean" good ground

    Also make sure your gas filters are in correct flow direction

    It's a cranking issue so this leads me to electrical gremlins and isomething is getting hot like circuit breaker and resets


    (it's getting fuel and starts) not cranking and cranking and cranking and won't start issue

    Your ignition box (stock) does mess with your timing by making timing changes electronically
    Make sure all of your grounds are clean and tight with dielectric grease for overkill


    Timing and idle air mixture are directly related

    Sounds like you didn't touch timing so set carb to factory Base line because you had it apart

    Don't Don't don't touch your timing it ran before and starts up now
    You are messing with simple issue
    Frustration will set in don't let it beat you

  7. #7

    Default

    Thank you to all. I will definitely take everything into consideration and look into each possibility until I catch the culprit. I will keep this thread updated. Again thank you guys for all the advice.

  8. #8

    Default

    Mine is missing. The PCV is there but just a hose goes directly into carb.

  9. #9

    Default

    Thank you for the knowledge.

  10. #10
    FEP Super Member gr79's Avatar
    Join Date
    Jun 2009
    Location
    SE Michigan
    Posts
    5,141

    Default

    I use the yellowish-tan colored Ford F2AZ-19584A (XG-12?) Electrical Grease in low voltage connectors.
    Say if the old stuff is dirty, needs more, or in a new bulb socket.
    Not cheap but 2-3 oz tube goes a long way. box says Ford spec ESB-M1C158-A.
    Its the stuff that's already on there from factory. No silicone in it according to the MSDS
    High film strength silicone dielectric on high voltage. Spark plug boots for one.
    Low film strength electrical grease on low voltage. Switches, contacts, electric motor bearings.

    Read that if dielectric grease is gobbed on, it can prevent electrical contact.
    Not so with electrical grease within reason.

  11. #11
    FEP Senior Member
    Join Date
    May 2016
    Location
    Lake City Pa 16423
    Posts
    510

    Default

    What do you mean by "it won't turn back over"? Does it crank normal or slow like the engine is getting tight? If it's the latter, the starter's will heat soak and cause it to not crank over normally.

  12. #12

    Default

    It cranks fine. The starter is a new high torque mini starter. It just wont fire up. I am getting fuel to the carb though.

  13. #13
    FEP Member
    Join Date
    Jul 2010
    Location
    Winnipeg Manitoba Canada
    Posts
    133

    Default

    I'm surprised no one mentioned a bad coil.
    That's where I would look first with regard to heat related issues.

  14. #14

    Default

    If it’s a duraspark then I vote for the ignition module.

    I went through a similar random not start when hot or even die randomly when driving problem with my sons 80 cobra. Swapped almost everything else on the ignition system but the module and it turned out to be the module...go figure. Changed it and no trouble ever since.

  15. #15
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Location
    Grand Junction, CO/RR TX
    Posts
    14,206

    Default

    Quote Originally Posted by Monty78 View Post
    I'm surprised no one mentioned a bad coil.
    That's where I would look first with regard to heat related issues.
    Actually mentioned in post #4.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  16. #16

    Default

    Duraspark is what it has. I have read that those are rarely an issue. I will replace the battery ground wire and also replace the ignition module in the column and see where it leaves me. Those are fairly cheap components. Since I just got the car it may not hurt to replace that stuff anyhow. I really don't like the terminal connector that is on the ground wire any way.

  17. #17
    FEP Super Member bwguardian's Avatar
    Join Date
    Jul 2010
    Location
    Houston (Clear Lake), Texas
    Posts
    4,668

    Default

    bwlsn13, what part of H-town are you located?
    HAD
    '82 GT monochromatic (red)...black cloth

    HAVE
    '85 GT vert two tone (white on charcoal)...white leather
    '00 F350 two tone (white on silver)...gray cloth
    '00 Excursion Limited two tone (white on tan)...tan leather...wifes ride
    '08 Taurus Limited ice blue...tan leather...daughter ride
    '08 Edge Limited white sand tri-coat metallic...tan leather...other daughters ride

  18. #18

    Default

    Deer Park. I have seen your ride around town. Beautiful.

  19. #19

    Default

    Ok yeah we must have read basically the same info on the duraspark modules being bulletproof but wasn’t the case for me. That kind of influenced my decision not to replace it till the last and sure enough. Oh well live and learn a bit. I don’t think modules are that expensive necessarily.

    It may turn out to be something else too. Intermittent problems are not fun sometimes

  20. #20
    FEP Power Member Jerry peachuer's Avatar
    Join Date
    May 2014
    Location
    Royal oak Mi
    Posts
    1,447

    Default

    Quote Originally Posted by bwlsn13 View Post
    I have a stock 1985 Mustang GT. Just a had the carb rebuilt with a Holley trick kit. Put in plugs, wires, rotor, and also a new mini starter. The car starts up fine when cold. After it gets warm is when it starts to act funny. Once you kill the engine (if it doesn't die on its own) it will not turn back over. Once you let it set for 10-20 minutes it will fire up again. Any thoughts?
    I misunderstood the "not turning back over" as a starter luggin or not cranking
    So the ground seems less likely ..

  21. #21

    Default

    While the Duraspark may be fairly robust, mine lasted about 33 years, I would not say they are bullet-proof. I replaced it, not because it failed to run, rather the electrical potting oozed out of it. I would replace it first, as it is easily accessible and not overly expensive.
    1985 GT owned since new

  22. #22
    FEP Super Member Bryan Knebworth's Avatar
    Join Date
    Sep 2010
    Location
    Lexington, MA
    Posts
    2,777

    Default

    Not sure if anyone has touched upon this, but is your car experiencing heat soak? I had a car in high school, that would not immediately start back up after an hour or so of driving. You'd have to wait another hour for it to run again. Luckily that only happened once!! Might be heat soak. If its slow to crank, the starter is overheating. Cars with headers sometimes experience this problem.
    Last edited by Bryan Knebworth; 12-11-2019 at 07:13 PM.

  23. #23
    FEP Super Member erratic50's Avatar
    Join Date
    Dec 2016
    Location
    Nebraska
    Posts
    4,575

    Default

    What happens if you give it two good stabs of the accelerator pump before you try to start it?

    not firing? Could be something causing it to flood. Faulty float, float level too high, etc

    What happens if you floor it and hold it there and crank

    I would also read up on ignition test procedures and ohm everything out in detail

    Make sure of the ignition type — people swap that stuff all the time and there are different problems based upon ignition

    hell — old points setups need 12V when cranking and 9 when running. They start like **** on 9. They burn points up on 12.

    BTW — the term “hot wiring a car” actually comes from jumping a 12V lead to the ignition and forcing the starter solenoid to engage ..... damn good thing there weren’t more thieves and so many just don’t know this **** anymore

  24. #24

    Default

    I'll chime in on the Duraspark box, they are far from bulletproof. Usually when they fail it is like someone turns off the key. Driving down the road it just dies, you coast to the side it won't start. You wait, walk home, etc., come back and it starts right up. That is the sign of a failed Duraspark box.

    The distributor pickup can also fail. It usually fails one time and then it never works again.

    Coils? I have rarely seen a coil fail but it happens. The weirdest coil failure I remember was one that would run fine in all situations except when you went around a left turn at speed, then it would just fail. As soon as you were back straight it would catch on go. That took a while to figure out.

    Good luck.
    Kenny

  25. #25

    Default

    The initial fire up is okay. It's after it runs for a while and then get turned off is when it doesn't want to start back up. It doesn't seem to be getting real hot though. During the Christmas break I with make sure I have the solid ground and replace the ignition switch. After that if there is no improvement I may look back at the carb and do a bit more reading. I kind of got sidelined with the kids and all. I really appreciate all of the feedback. I cant tell you how cool it is to have people like you guys responding to a request for help. I'll keep this thread updated.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •