[94Trans-Am]

Well I just had the intake off to do the well documented oil leak from the lifter valley and although it was a f%^*^"£%g pain it went pretty straightforward.
So feeling smug thinking most of the annoying jobs are getting sorted out up pops another one.
When the car has been on a run and for instance, you stop for fuel, the car will barely turn over. Give it a couple of minutes and it spins over fine. Its perfect from cold but it only starts this when hot. Battery and starter were new at the end of last year all wiring has checked out ok, the car is running at normal temp.
The headers are about a quarter of an inch from the starter solenoid.
I'm sure its heat soak, has anyone else had this and what did you do to cure it ie, make a heat shield, exhaust wrap , mini starter etc.

 

[cocobolo95]

I had the same problem with my 90 camaro dd. After checking what I thought was everything, I decided to clean off 23 years of gunk where the - lead of the battery connects to the engine. Sure enough, once I could see the bolt holding the - batt cable to engine, it was just loose enough to add enough extra resistance to the circuit. So when engine was hot, starter wouldn't turn over very well. Cleaning and tightening solved my problem.

 

[94Trans-Am]

Well that's sounds a possibility, will get on it asap. Thanks.

 

[94Trans-Am]

Had a look underneath at the earth cable, sorry to say it looked pretty good and tight, I undid it and cleaned it and tightened it as much as possible just to be sure.
I cut a 10" length of exhaust heat shield of some scrap stuff and using a single worm drive clip [around the middle of the tube], I now have that between the downpipe and the solenoid just in case.
When I get round to taking the headers off [it needs new header gaskets at some point] I will make a neater job.

 

[1_black_LT1]

Get a voltmeter.
What does your battery read, with car off.
What does it read with the car running?

Gotta start with the basics, just to make sure.

 

[94Trans-Am]

Before all this started I had trouble with the moulded [mouldy] battery positive terminal. I had to fit standard new terminals and went through all the connections, the charging rate [after starting] is about 14.75, battery voltage is fine. [I also fitted a new starter and battery as the old starter tended to "rattle" if you shook it].
This only happens when the car is very hot, like after a long run, it will stop and start all day long if its not red hot, although I let it sit and idle until the fan almost kicked in, and it did start immediately after shutting it off. So i'm hoping my cheap heat shield or cleaning the engine earth might have helped. Wont find out until I go to a car show this sunday as i'm working flat out until then.

 

[94Trans-Am]

Ok this is weird, I went out this morning, [fairly cool day] it started first time, drove 3 quarters of a mile to get fuel, switched off, topped up, paid for it, came out [total time 5 minutes] and it sounded flat again, slow to turn over no start, waited about a minute and it fired up. Drove 40 miles to show, [won best Pontiac out of 5] and it failed to start immediately after getting there but started 1st time when leaving, drove back 40 miles, parked in driveway, started first time ????

I should add the voltmeter seems to go very low when this fault occurs.

I'm thinking of renewing the battery cables as i'm getting stumped, does anyone know what diameter the terminals are ?
And roughly what ampage the cable is?
Thanks.

 

[cocobolo95]

With battery cables, bigger is better. The factory cables are just adequate for the job when new. So if you can go with a bigger cable, you may have buy bulk cable and crimp your own ends. But if your problem is due to the cables, the bigger ones will give you better service.

Factory + cable is 19mm which equals 4 gauge wire. Factory - cable is same size.

I would go to a 0 gauge cable for both + and - This will give a big enough reserve to overcome heat soak, if you have no other problems to overcome.

I don't know what metric size 0 gauge translates to.

 

[94Trans-Am]

BATTERY POWER EARTH CABLE 16mm STRAP STARTER MOTOR LEAD, VARLEY, LUCAS BATTERY | eBay

These are what i'm looking at I can get them with only one end and can sort out the battery terminal myself.

 

[terminal_crazy]

I had the same problem with my 90 camaro dd. After checking what I thought was everything, I decided to clean off 23 years of gunk where the - lead of the battery connects to the engine. Sure enough, once I could see the bolt holding the - batt cable to engine, it was just loose enough to add enough extra resistance to the circuit. So when engine was hot, starter wouldn't turn over very well. Cleaning and tightening solved my problem.

I suffered for years with my '78 Camaro. Eventually traced it to a worn stud in the solenoid. Always fine cold. Hot starts were rare unless you left it for 5 mins to cool off.

I always attributed it to the headers & Battery in the trunk.

My '95 Z28 also suffered since I put on Mac Midlength Headers.
After the cam upgrade it got worse.
I plan to have it sorted after the Rebuild.

Mitch

 

[cocobolo95]

The cable shown in your link will be taking a step backwards as 16 mm is even smaller than the 19 mm cables the car came with.

Funny thing about wire, US gauge sizes, the wire gets bigger the smaller the gauge number.

With metric wire, it's exactly the opposite of US gauge sizes. In mm the bigger the number the larger the wire size, as metric wire numbers give the exact conductor size.

 

[94Trans-Am]

Great.
But thanks for pointing that out, I will search out some thicker cable.

 

[94Trans-Am]

BLACK BATTERY POWER CABLE 16 25 35 50 70mm2 EARTH STRAP HEAVY DUTY STARTER LEAD | eBay

As these are 16mm to 70mm I was going to go for the 25mm which is 170 amp.

 

[cocobolo95]

Now your on the right track. The 35 mm diameter would be ok, but as stated before, in battery cables bigger is better. If you spend the extra money on the 50mm or 70 mm, they will give you that much extra reserve. So as they age and get battery acid corroding them, they would still have enough power carrying capacity to start your car and run your equipment.

Point to remember, factory + cable has the alternator lead built in. So it's a double cable. But you can use a new single cable and just make a new alternator cable. Factory alt cable size is 8mm. It wouldn't hurt to go a little bigger on that also. Like the 16 mm you were looking at for the starter cable.

 

[94Trans-Am]

Fortunately when I converted to standard battery terminals I separated the 2 positive cables so fortunately that's already sorted, but I will be renewing any other cables that look a bit tired.
The reason I went 25mm was because that's the biggest cable that will go into the battery terminals I use without having to trim them down.
Thanks again for the pointers.

 

[94Trans-Am]

Sorry to dig this back up but just to let you know it now starts first time every time.
I couldn't see anything physically wrong with the cables but I renewed basically all the cables that come off the battery, making the smaller ones myself.

 

[cocobolo95]

That's the thing with wires, a visual inspection only shows some of the problems. In wiring, what you don't see, can hurt you.