starting problem when hot - Page 2

paulbarrick · #21 (**permalink**) 03-02-2009, 04:23 PM

I appreciate everyone's interest in my hot start problem. I believe I have solved the mystery!!!I took the negative battery grounding cable loose where it connects to the roll cage bracket...that runs to the frame. It seemed tight, but when I cleaned it and reconnected it guess what....the car starts better than ever and after running for awhile it starts great. The more I studied my problem, the more I became convinced that it was a grounding problem. I cannot overstress the importance of checking grounds especially with these fiberglass cars. I am going to check and clean all of mine because I hate being redfaced when the Snake won't start. The sun is shining bright on my Ol Kentucky Home!!!!!!

Blas · #22 (**permalink**) 03-02-2009, 05:03 PM

I can not stress how many electrical gremlins can be explained by improperly crimped wire ends and the worst offender by far - poor grounds. That's why I always suggest checking them first before spending any money....Congrats on the excellent detective work...

CBattaglia · #23 (**permalink**) 03-02-2009, 07:30 PM

When in doubt, listen to Blas first....!!

undy · #24 (**permalink**) 03-03-2009, 03:47 AM

Quote:

Originally Posted by Blas

I can not stress how many electrical gremlins can be explained by improperly crimped wire ends and the worst offender by far - poor grounds. That's why I always suggest checking them first before spending any money....Congrats on the excellent detective work...

Quote:

Originally Posted by CBattaglia

When in doubt, listen to Blas first....!!

Hmmmm... i thought that had been stated before the winning problem diagnosis was announced

Quote:

Originally Posted by undy

Do a couple electrical checks first:

A healthy electrical system is essential to good cranking, especially with a hot motor. A deficient electrical system can have enough juice to crank a cold motor that's not up to clearance specs, has a tad less compression and "looser" clearances. ...but when things are heated up and more cranking amps are required, it just doesn't quite do the job. I'm not saying this is definitely your problem but the basics need to be checked first.

1. When hot, car off, nothing running, put a volt meter across the terminals
and check battery voltage. It should be 12.0 to 12.5 or so. Next, with car
hot, have someone crank the engine while you check the battery voltage.
It should be around 10.5 to 11 volts. Measured in the same fashion, your
charging volts at idle with nothing running should be 13.2 to 14.5 volts.

2. If the voltage readings above seem normal then you need to make sure
you're getting full battery voltage all the way to the starter. Loose
connections, inadequate wire sizes and defunct starter relays can cause
voltage drops. These voltage drops can cause exactly the problems you're
experiencing. This is the easiest way to check for a cranking voltage drop.
Get about a 6' piece of light gauge stranded wire and strip one end back
an inch or so. Disconnect the negative terminal on the battery. Put the
front of the car in the air, on jack stands. Crawl underneath and loosen the
starter positive terminal stud nut (noting the connection and how tight it
was in the first place). Wrap the stripped end of the 6' piece of stranded
wire around the starter stud and tighten the positive terminal back down.
Feed the stranded wire out from under the car. Drop the car and
reconnect the battery. While cranking the car read voltage from that
stranded wire to the positive side of the battery. You should read less than
1/2 volt. If you read more then you have connection problems, inadequate
wire size or a defective starter.

Note: This type of test should also be conducted on the ground side too,
done in a similar fashion. While you're under the car, ensure the
starter bolts are tight and the same on the engine to frame
grounding strap.

I'm running outta go juice so .....

Dave

Ronbo · #25 (**permalink**) 03-03-2009, 04:13 AM

At some point you should just run the negative on the battery directly to the block and have a jumper from the block to the frame.

No-Lox and star washers on all connections.

(copper anti-seize is a good substitute for the No-Lox)

Fiberglass or not, relying on the frame for ground connections will provide hours of irritation.

Blas · #26 (**permalink**) 03-03-2009, 05:21 AM

Undy,
Your explaniation was excellent. I was just pointing out the fact that many gemlins electrical or otherwise, do not always require new parts and $$$ to fix... just some time and detective work...If we could just fine a way to make fibergalss conduct electrictity ...

paulbarrick · #27 (**permalink**) 03-03-2009, 05:29 AM

I will take that thought and run with it, certainly makes good sense, wonder why the guys when they build these toys, don't do these little things that seem to cause so many problems for us guys who just want to get in, start up and smoke some tires?

Wayne Maybury · #28 (**permalink**) 03-03-2009, 06:14 AM

I learned many years ago that when in doubt, check the grounds. I had a 24 ft house trailer that was driving me nuts. I had checked every electrical connection, fuse, whatever. The electrical gremlins would not be controlled. Finally I disconnected the main ground and found that the steel frame was rusty making a poor ground connection. I cleaned it up, reconnected the ground, and all of my electrical problems disappeared. I now always start by checking the ground connections if having any sort or electrical problem.

Side note; I also ran a ground wire from the Le Mans gasoline filler cap to the frame on the Cobra just to make sure that the filler is properly grounded. It may not be necessary but it only took a couple of feet of wire, a couple of crimp connectors, and 10 minutes of work. Better safe than sorry.

Wayne

undy · #29 (**permalink**) 03-03-2009, 07:34 AM

Quote:

Originally Posted by Blas

Undy,
Your explaniation was excellent. I was just pointing out the fact that many gemlins electrical or otherwise, do not always require new parts and $$$ to fix... just some time and detective work...If we could just fine a way to make fibergalss conduct electrictity ...

The point in my post was the advice to take some electrical readings before one just inadvertantly starts replacing, taking things apart, cleaning, putting things back together and hoping for the best. If you run voltage/continuity checks prior to taking things apart then there's no mystery on the fix.

Ya mean I've got to take all my fiberglass ground straps off??

Dave

Rick Parker · #30 (**permalink**) 03-03-2009, 07:37 AM

The Starter Solenoid, whether remote or built into the starter can often be the culprit.

Blas · #31 (**permalink**) 03-03-2009, 07:37 AM

Ya know, adding a ground to the gas cap is an interesting thought. The cap is bolted to fiberglass and isolated by a rubber connecting hose on the tube, at least mine is. I guess you could look at it two ways. The cap is isolated and should not be a problem or its grounded and should not be a problem...Think I'll run a test to see if it's grounded with an OHM meter tonight....Anyone who also has a vette in the garage could also check it to see if it's grounded. GM surely would have thought this issue out....

Ron61 · #32 (**permalink**) 03-03-2009, 08:27 AM

Blas,

The one on my Cobra when I had it wasn't grounded. I got under there and used a heavy wire and clamp to ground it to the frame. I had to remove the rubber hose that I had in order to get a good place on the caps mounting to connect to then put the hose back on.

Ron

Blas · #33 (**permalink**) 03-03-2009, 10:18 AM

Ron,
I guess the question really is: Should the LeMans cap be grounded?
If the filler is isolated, theres no way to get a static discharge when fueling up....
I know in the old days the filler pipe was part of the tank, and the tank was bolted to the frame...Especially so in metal cars...so everything is grounded.
It's an interesting question that I don't have an answer for...and could probably make an arguement for either way if necessary.
Something to do till spring comes....

Wayne Maybury · #34 (**permalink**) 03-03-2009, 11:38 AM

Blas

Here is the reason that I grounded my filler cap. I have a fiber glass sailboat equipped with a small diesel. When I had a survey done a few years ago for insurance purposes, one recomendation was to ground the metal fuel filler cap. I knew this was rediculous as there is virtually no way to ignite cold diesel fuel with a static spark. Nontheless, I did this since it was recommended in my survey and I didn't want the insurance company to have anything to complain about.

That got me thinking about the metal filler on my fiber glass Cobra. Since the Cobra is fed 94 octane, not diesel fuel, I thought that it wouldn't hurt to ground the filler cap.

Wayne

Joe Wicked · #35 (**permalink**) 03-03-2009, 11:52 AM

If you have a different static charge on your filler cap than the pump you risk a discharge. By grounding the cap, you ensure the cap has the same charge as the frame. When you get out of the car, you will generally equalize the car to ground, and thereby discharging any charge. Think of how many times you have gotten out of a car (espcially in the winter with the heater on) and gotten a small discharge/shock. If the gas cap retains this charge, it can discharge when you touch the gas pump nozzle to the filler cap. If the charge is the same, there will not be any discharge. It is a good practice to touch the gas cap area with one hand and the pump discharge plate with the other no matter what car you drive before pumping. This will eliminate a discharge chance during fill up.

Ron61 · #36 (**permalink**) 03-03-2009, 12:18 PM

Blas,

I didn't do mine because I thought it had to be or for legal reasons. I just did it to satisfy myself. I try to be extra careful when dealing with gasoline or anything that could cause a fire or explosion. True, I have only seen one car catch fire from a static charge and it wasn't a Cobra but a Chevy. But I also had more ground straps than most people use. My battery was in the trunk and I had a short ground strap from it to the frame. Then I had two big ground straps from the block to the frame. I then took a terminal strip and mounted it to a place I could get to easily and grounded it to the frame. That way if I needed a ground for something I could just go to that terminal strip and use one of the terminals. Just my being Paranoid I guess and overdoing the safety stuff.

Ron

Blas · #37 (**permalink**) 03-03-2009, 01:46 PM

All really good points guys...All in all a very interesting discussion...
Erroring on the side of safety is always a good idea...

Let me throw this thought out...
Lets say you and the car did in fact have a static charge, after exiting the car, you touching the gas pump should equalize that charge on you. Then, you take that gas pump filler nozzle and move towards the cars gas tank. Wouldn't the car still have the static charge like you had when you exited? You touched the pump and are now neutral, if the LeMans filler neck was grounded wouldn't it then discharge to the gas pump nozzle? Where as if the filler neck was not grounded, the static charge from the car is isolated from the gas pump nozzle.
I would still be cerious as to the grounding design on the filler on a regular fiberglass production car like a Corvette....
Anyone got a network contact to that TV program where they prove or Bust myths like this?

Blas · #38 (**permalink**) 03-03-2009, 04:01 PM

OK....
As I suspected, The LeMans filler is not grounded on my SPF...so I checked both my of my other cars and they too are NOT grounded....I'll check my other two cars tomorrow...but I'm seeing a pattern here...perhaps my reasoning is correct and they should not be grounded...further thoughts anyone?

Jerry Clayton · #39 (**permalink**) 03-03-2009, 05:28 PM

Blas as you know I have been in aviation for many years----all modern jet airliners are bottom fueled to eliminate the static discharge associated with free fall fueling----

And this is after grounding the aircraft to ground rods thru the ramps, grounging the fuel trucks, and then grounding the truck to the aircraft--

Back to a car---a static charge will build up on your car driving along ( if fact, the lamans filler at high driving speeds can build up quite a charge from the air flow around it), now you stop for gas---your charge gets transferred to the pump, along comes another car, ditto, ditto again and again----then comes a tanker that got a big static charge filling up at the refinery after a tunderstorm, drove 600 miles to the station and goes to offload his fuel-----there has been enought differential charge built up to ignite the truck--- do you want to be there?????

Bond the filler to the tank----someday it could save your life

Blas · #40 (**permalink**) 03-03-2009, 06:37 PM

Then why are both my Mercedes not grounded at the fuel filler? I'll check the Passat tomorrow and the Porsche over the weekend...Take an ohm meter out to your car and check it....I'm not doubting what you are saying, just compiling the facts...I think you can make a compelling argument either way...I can't speak for airplanes or boats as I have no first hand knowledge on them. Guess we need to check a few more production.cars..Anyone with a Kirkham care to add to this discussion?