Expert: Ernest (Ernie) Kenward - 5/3/2007

Question
QUESTION: I'm thinking that the car has the same attitude as it's OWNER (my 17 year old son) but he's just not convinced....so I'm looking around the net for help because the poor kid is all over the place with this car he loves so much.

Here's the problem.  He's got a 1989 Mustang GT 5.0.  Looks good, sounds fabulous and it's a great chick magnet.  The problem is that it randomly refuses to start. He's replace the battery and alternator already.  

Random is very random (I've driven it too and been stranded).  It doesn't matter if the car is hot or cold. Sometimes it will restart in 5 minutes, sometimes it takes overnight. When I drove it and got stuck it took a lot of creative cursing but I don't think that's a mom-to-child option I can offer to him (yet?).

What happens when you try to start it?  CLICK. CLICK.  That's it. Then at some point it will start up again just like it should.  Interior stuff is all lit and it's not flaky any other time except what you'd expect from an older car.

Any suggestions or directions to go next?  Did I mention that he's broke and I'm separated, broke and overwhelmed?  HELP PLEASE!  He's a good kid, doesn't ask for much and the car means a lot to him so I really appreciate any time anyone can give me so I can guide him from here.


ANSWER: Here is a "further-to" answer:

I had a chance to think a bit more about the problem, and it also helps that I reread your note; it answered a few questions I was going to ask.

The core problem, if I understand it correctly, is that the car's occasional not starting is that the starting motor will not turn over when the key is turned to "Start" on those occasions.  However, you do hear the "CLICK" each time you turn the key to start.  That click would be the starter contactor (solenoid too, in some cases - not sure about the 89 Mustang until I check a manual we are lucky enough have around) pulling in.

Happily, I think the problem will turn out to be quite simple to solve.  This is likely a matter of a loose or corroded connection in the high-current circuit feeding the starting motor.  

Most likely, the heavy lead from the contactor to the starter motor itself is going open.  A visual inspection might show that the connection of that cable to the terminal on the starter is loose, and perhaps a little heat-stressed.  If the connector otherwise looks okay, I would take it off, clean it, apply some terminal grease, and then reassemble it and torque it down to specifications - about 10-15 ft-lbs if it is a 5/16 nut.

Another place to check would be the connections at the contactor itself; clean, grease and retighten those if need.  Too, there may be an internal problem with the contactor itself; if the problem persists after dealing with all connections, consider replacing this.  They are pretty cheap bought as a part, (and your son could probably do with the experience!)  

Finally, how good are the cables and connectors right at the battery?   If in doubt, take them apart, clean and regrease.

All of the above is a part of a good preventative maintenance regimen anyway.  The best problem solution is those anticipated and applied BEFORE a problem has a chance to happen!

As to terminal grease, "Fluid Film" is one good product, available at many auto parts stores or jobbers, but there are many other good ones as well.  The grease to look for is a light product, non-conductive and suitable for use on electrical connections of all kinds.  The purpose of the grease is to act as a barrier to water and chemical elements that could cause corrosion and thereby increase the resistance of the joints.  High resistance joints also get hot (I-squared * R) and can begin to burn out.

This car could be the start of a good practical course in engineering for your son.  Lots of good books on automotive topics at those auto supply houses, and at the library.  The Haynes manuals are not bad either as a learning guide to many cars.  (On balance, they are not terrific either, as they tend to lack detail on systems unique to some cars, and they do have the odd error.  If one starts off with the Hayne's manual, and then graduates on to the manufacturer's shop manuals however, one will get to know the car well.)

Hope I helped.  There might be other avenues to explore, but this problem has all the hallmarks of one of those that just takes careful investigation to find and only properly-applied labour to solve.  Good luck.

UK?  A couple of generations ago.  Try west coast of Canada, as in greater Vancouver area.  There is a fairly sizable ex-UK contingent in the Yvr area, but "cheers" seems to get around everywhere ... or maybe it's just us in academia.  Who knows?

Have a good day, and I hope the problem is speedily resolved.

Cheers again ... EGK

original reply:
I have to give a lecture in the next few minutes, but let me make a comment for the moment, and get back to you further later.

I am thinking "electrical intermittence" as being the most logical culprit, followed by an electronics intermittence at the microcontroller circuit board.  Either can be thermally related, that is, as connectors and/or components expand with heating, non-bonded connections open.  Very irritating problem, as Murphy plays a role all too often - intermittent problems almost NEVER surface when one is actually looking for them.

More later.  Cheers ... EGK

---------- FOLLOW-UP ----------

QUESTION: You are an ANGEL Ernie, thank you so much( I gave you top ratings at the site of course!).  My son threw out the car manual --- you guessed right, I told him to keep it but as usual I'm the dumb mom who doesn't have a clue(although I do have a sense of humor-lucky for him!).

I tried to suggest last night that it might be a connection problem (I skimmed your answer and will print and read it more carefully once I finish typing) but my son didn't listen.  Maybe if you say it he will consider that before he throws even more money into parts and repairs.

Yes, you were right.  It clicks just as you would get if the starter was bad but my gut says that it's not the starter.  It's 100% random. He went 2 months without a problem then it started again. It's sporadic and the car springs back to life when it feels like it, not by any time or interlude so when it dies we just keep going back and trying it till it restarts again.  

Thanks again so much!  Your info was the inexpensive easy solution before we would have to move into replacing starters and cellunoids(sp?).  

This is my first time on this site and I'm very happy!

Rachael

ps.  I was selling online for quite a few years and only my treasured UK customers used 'cheers'  :0)  

Answer
Glad to be of help, and know that I am highly sympathetic.  Neither my eighteen-year-old son nor my about-to-be-sixteen daughter put much stock in my observations or advice  -unless they crash their computers or have problems with the DVD player!

As Samuel Clemens (Mark Twain) once said: "When I was fourteen, my father [any parent, of course] knew absolutely nothing.  However, by the time I was twenty-one, I was amazed by how much he had learned in seven years!"

This too shall pass!

Let me know how this works out.

Ernie Kenward
BCIT, School of Electrical & Computer Engineering
Burnaby BC Canada