QuestionI have a ford 86 f150 pickup, when it is cold, it starts great, when it runs for a while, gets hot, it will drag and finally start. I had the time set at ford service center. I have replaced everything electrical, plugs, wires, three coils. Is it the cable coming from the starter. Could that be the problem? Or what is not working correctly not allowing it to function/start when it gets hot?
AnswerHi Danny,
When your engine and accessories get hot the tolerances for clearance vary also. When you start your engine cold, the aluminum pistons are looser in the bore as well as larger gaps in between the bearings and other valvetrain components which makes the engine turn-over easier. When everything heats up, the tolerances are reduced and your starter motor will require more amperage to spin the engine fast enough for it to start.
My first guess is that the starter has seen better days and is probably ready to be swapped-out for a newer model but before you go buying a starter, clean the battery terminals and make sure the cable is not frayed going to the solenoid and that from the solenoid to the starter cable is in decent shape also. If the cables are good and the terminals clean, good power is making it to the starter which means it must be the issue. The battery can have a dead cell too which would usually only act-up when warm, we'll address that in a sec.
If you have a good multi-meter that reads voltage, connect it to the battery when cold (record the reading) and have someone turn over the engine with the coil disabled so the engine does not actually start. Have them hold the ignition in the START position with the engine turning over for a count of TEN SECONDS while you observe the total voltage drop in the battery on the tenth-second. <-- VERY IMPORTANT! So, if you connect the tester and it reads 12.75 volts but at the tenth second of the engine turning over it reads 11.08, good, record the reading and move on. The numbers I have here are only for reference, if you get the same readings, I'd be surprised.
Next, warm the engine up by taking a ride or something until the engine gives you the slow-start. Then re-perform the test above and observe the readings at first hook up and at the tenth second of the starter test again. If the end reading drops below 9 volts (8.99 volts or less), replace the battery and start from the beginning again. If the end readings you get are nearly identical, the solenoid on the fender is most likely the culprit and if the reading drops more than the first one but stays above 9.00 volts, the starter is probably the issue.
I am assuming that when you say it 'drag' starts, that it is turning over fine, just slow. You don't mean that the engine is STOPPING while it is trying to start. Like a half-spin, STOP, half-spin, STOP, half-spin, STOP, etc. If it is doing that, then retard the ignition timing a few degrees (regardless of what the 'dealer' says the timing should be set at or is set at) because it is pre-igniting the fuel mixture in the cylinders and that will cause detonation and possibly engine damage pretty quickly. Your engine is not designed to spin backwards for any amount of time.
Good luck.
Looking for a reputable service technician? My advice on finding a good technician is: Steer clear of the dealership and 'chain' stores like Firestone, Sears, Pep Boys, Monro Muffler/Brake, Midas, etc. as they usually only employ ONE ASE Certified Tech just so they can say they do and chances are, that guy is the asst. manager or manager and is not in the store to diagnose/repair vehicles anyway. Find a service location in the link below or get some names out of the yellow-pages and do a drive-by. Garages that employ ASE Certified Technicians will be marked with the 'Blue-Seal' insignia. If unsure about whether a place employs Certified Techs, just ask to see their credentials. ALL ASE Certified Technicians will be PROUD to show and display their certificate(s).
Thanks for the question, I hope this information was helpful to you.
Fred
Knucklebusters Used Auto & Truck Parts, Inc.
www.knucklebusters.us
570-453-0910
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