Yes it is strange but why I ask if it is a cheapo unit from Autozone, Pep Boys, etc

 

It is a 4L60E with a controller-the 700r4 uses a TV cable for a controller. That is my whole question -why does every change work for only a couple of months? When the starter works it starts immediately hot or cold. I just reach thru the window and don't even have to get in the car.

 

The transmission itself, of course is not the issue, we can rule that out.
The problem is either electrical, or mechanical, those are the only real choices.

We know that you have power supply, is it enough?
It is intermittent, kind of, so are the connections right? Are the grounds solid? Is the wire in good condition and routed, mounted properly? Is the power supply correct, as in cranking amps? If all of this checks out, then it is mechanical, yes?

Is the starter the right one? Does it have enough power? Is it aligned properly, or is it struggling to engage the flex plate? have you tried having someone turn the flex plate while you inspect the teeth for irregularities, shaved teeth, scrapes from the starter gear, etc.? These are the kinds of things that can cause stress on the solenoid and thus early retirement.

Then there is the heat factor. I know you said that it works better when warm, which might be strange. However, could the continuous heat cycling cause the springs and other internals to misshape, and perhaps this shows itself more when cold, as if when they cool down they contract out of shape, and loosen up when warm? That's just a possible theory I'm tossing out, and could be way off base.

I'm just trying to think of a logical explanation as to why it would work fine in the beginning and then degrade over a relatively short period of time.

Of course, faulty new parts is always a possibility.

 

OP - to fix since you're not interested in sharing information that's been asked. I'd do this. If the chassis is a custom tubular fabrication a ground to the chassis at rear might be assumed good enough BUT if this build is a combination of frame rails and cross-members being welded/bolted along with a multitude of bracketry I'd want a substantial ground all the way to the engine block - battery to engine block non-stop. In your case, regardless of how the ground is now I'd question it and do it to engine. I'd have a ground alternator to the engine NOT relying on the brackets and mounting. Multiple braided straps engine to chassis and the body sheet-metal.

I'd question all of the terminations on all of the cables that are in use now - all of them. What type of distribution buss/box is used? I believe that I'd redo the ignition switch terminations from the buss regardless. I'd do a new wire from the ignition switch to the S-terminal on the starter. You maybe need to question the condition of the contacts and plunger IF you used an OE style 'Denso starter - the click, click, click I believe is the result of poor terminations and likely poor contacts/plunger in the starter that get worse with every repeated click, click CLICK!

If the starter is still warranty maybe you exchange it and check the plunger/contacts of the replacement before install. Just buy new and do the contacts/plunger in the replacement if you question the appearance of either the NOW or the exchange.

I asked earlier if all cable was "fine wire welding" and you didn't offer up answers. If they ain't 2/0 "fine wire" they need to be - 1/0 ground I'd think satisfactory. What battery group is used?

I don't get the NO NSS - really - foolish!

You don't want to hear this but once done you do a "load test" of CRANK & CHARGE - I'd consider a "parasitic load test" also assuming this maybe, battery charge diminishes while sitting and after running and charging the wiring deficiencies are overcome with the higher voltage and you get the expected CRANK!!

****All of this assumes that there was no remote external solenoid added that would require substantial modifications.

 

Battery is 850 and 675 cold. I like your idea on the ground cable. It is a custom tubular frame. Does the ground have to be as heavy as the hot cable? I cant tell strands because the ends are put on so well you cant see the cable. I think your crank and charge is the removal of the surface charge which is hardly nil. I sold auto parts for years and checked , charged, and tested batteries a couple times a day with a carbon pile tester so I feel well versed in that department. I usually sold the hot rod guys 6 volt cables because of the larger size to cover the higher Amp draw. I will try your cable idea but it will probably be a while as we are going into a winter deep freeze starting this weekend. By the way I had a 90 ZR! which I sold 3 years ago and sometimes regret it other than the fact of replacement parts being non existent.

 

What is the part# and brand of the starter that is on the car NOW? Battery is what group? Side terminal or top post?

Part# from an invoice and not from a quick check for applications, there's many that would fit but only interested in "what's on the car now"! When I mention checking CRANK & CHARGE it's an evaluation of the complete system. You mention "selling auto parts" and should understand that #'s matter. You keep avoiding answers that require #'s LOL

 

Battery-24F70 CARQUEST top post. I took it out of my 409 Belair where it worked great since buying it 2 years ago. Worked great for the usual 2 mos.
Starter- Autozone Durolast DL 9981S. Worked great for around the usual 2 mos.

 

I had Durolast before. In short, it did not last. The fuel pump died in the middle of BFE and my starter wasn't the greatest until I had it rebuilt. Kinda why I asked you to have a rebuild shop disassemble it and check it out. Yes, they tested and declared that it was good.

 

That starter appears to be a PG 250(I think) and not a 'Denso as expected. Is it still in a warranty coverage? The 9981S seems to be a value-line product and not a "premium" product. I don't know exactly where you go with the starter! If you've got a quality starter and quality/efficient wiring you shouldn't have your issues. I really believe that wiring is the deficiency here. That starter doesn't have a serviceable plunger/contacts like the 'Denso so .....

If the starter isn't in a warranty situation maybe you just try a solenoid BUT there's a catch. A 250 doesn't generally have serviceable solenoid/plunger, there looks to be a couple possibilities. Would a marine unit be maybe more desirable? Maybe! Since a PG-250 seems to fit maybe you look further into a PG-250 - Here's a link that towards the bottom shows how a PG-250 is assembled note the **(for drive housing/solenoid/plunger). The PG-260 is directly below it and you can certainly see the reason for maybe considering either a PG-260 or an older 'Denso for the build. The PG-260 sometimes has a situation for mounting hardware. I believe I understand what to do there. I used a marine source so you can "visualize" the differences without going from "site to site" - see if yours doesn't appear to be like the PG-250. I know where to buy a PG-250 solenoid but the fork/plunger I'm not sure of.

http://www.boatfix.com/merc/techbk/95/95hga4.pdf

 

The 9981s is a value line product- the DL 9981S is the premium- the one I am using.

 

Let them replace it then. I guess it's very dependent upon the placement of the DL "DL9981S" does seem to change it LOL. You confirm your wiring and there shouldn't be recurring issues IF the starter is a quality build.

Understanding how the PG-250 is constructed maybe it makes sense that "heat" improves it's function. You supply a quality 12V signal to the solenoid you should expect the same cold/warm/hot!

 

Yes winter has set in and the 33 rests in an unheated garage. Replacing the starter will probably happen but the reason it is on there is because the starter that was on it when I got it did the same thing. Will probably replace the ground cable first but for now it is too cold to worry with. Thanks for all the info. and Merry Christmas.