# Starter won't crank after engine is warmed up



## 1967pontiac400 (Dec 10, 2020)

Hi all!

I'm new to the forum and I'm finishing up the restoration of a 1967 GTO Convertible.

The car starts okay, but after she's warmed up the starter does not really crank. Using a volt meter I can see that the current draw gets really low when I attempt to restart the vehicle after being warmed up - I'm not sure if it's a battery issue or a starter issue. I've heard that it's not all that uncommon for 400s to have starter heat soak issues but wanted to get some input here.

Thanks!


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## PontiacJim (Dec 29, 2012)

1967pontiac400 said:


> Hi all!
> 
> I'm new to the forum and I'm finishing up the restoration of a 1967 GTO Convertible.
> 
> ...


Often, there can be corrosion in the batter cables IF you did not replace these. But seeing you restored it, #2 problem can be that the replacement "new" cables are too small of a wire diameter. The store bought cables are not for our older cars, they work fine for today's vehicles. So this would be the first place I look.

Second would be the grounds. Make sure you have all your grounds - engine to frame, engine to body. You can check continuity on this as well. Make sure no paint is under any of the grounds.

How about the "purple" wire going to the solenoid? New? If not, another big area for corrosion to attack. Casing looks good, but inside up into the wire gets loaded with corrosion.

If all looks good with the above checks, then I would look at the starter for your problem. Starter solenoid's do go bad, but if new, your really should not have an issue this soon if you don't have many miles/time on it. Same for the starter.

If you have not had the starter rebuilt and/or new solenoid installed, I would do this. Keep the original starter if it is and have it rebuilt. It will save some grief with regards to shimming the starter as some remanufactured starters need to be shimmed so they don't grind - which could also be your problem. The pinion gear in the starter has to mesh correctly with the ring gear or it can bind, and when the engine is hot, it can be harder to turn.

Timing setting is also important. Just as a head's up. Too much advance and it'll want to crank hard. Assume the carb is not flooding as excess gasoline in a hot engine causes issues on starting.

So go for the wiring checks first, then starter, then possibly timing.


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## Noangelbuddy (Dec 6, 2017)

My 65 GTO had that problem. When cold it would start fine, but when the engine was hot it would barely turn over and failed to start. In my case, the headers were very close to the starter. We installed a home made heat shield, which solved the problem. Info may, or may not, be relevant in your case. I also experienced the timing problem Pontiac Jim cited. I had more power with an advanced setting, but then started having starting issues.


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## 66GTOHahira (Sep 5, 2019)

I am not a mechanic. I considered a heat shield for my 400 but the problem solved itself. I think there may have been some corrosion because the car had not been cranked in a while. It cranks very well now Hot or Cold. I replaced the battery but according to the store clerk, the battery was old but not bad.


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## Bob J (Sep 5, 2020)

I have had similar issues with my 64 GTO. Pontiac Jim's suggestion that the wires to the battery are too small would be where I look first. I believe that to be my issue. My battery is in the trunk, and while the wires are new (i think 2 gauge but not sure) a friend of mine who is really into the old GTOs and Firebirds said i should upgrade to a heavier cable. I think he said 0 gauge would be good....I'm not a mechanic either, but his suggestion makes sense to me. I just have to find the time to do it....BTW, while I have had problems with it not starting when the engine is hot, it does not _always_ happen... not sure if this helps or not


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## Droach6498 (Nov 1, 2020)

1967pontiac400 said:


> Hi all!
> 
> I'm new to the forum and I'm finishing up the restoration of a 1967 GTO Convertible.
> 
> ...


I had a 67 that had headers and if I drove it a bit I would have to park on a hill to start it eventually it fried the starter. I bought a smaller higher cranking one didnt have any problems for a year then I sold the car.I put a metal shield on it, no help. I thought of putting wraps on the headers but seeing the damage they can do I balked. Maybe wrap the exhaust at the starter.


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## Dukes67 (Jun 19, 2018)

I had the same issue with mine. All of what Jim mentioned was checked and still the problem persisted. I ended up getting a geared starter for the engine and have not had a problem since. The starter spins so fast now you could probably drive around on it.


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## 1967pontiac400 (Dec 10, 2020)

Hey all - thanks for the replies, this gives me a lot to look into. I have a high torque starter that I will be installing since the original one is super old and I'm also starting to suspect a battery issue.

The current battery is an inexpensive duralast and I hook up my trickle charger every few days to keep it topped up but it does not hold a strong charge for long.

Yesterday I finished replacing the power steering pump after some leakage issues and per the manual, I started the car off the ground and turned the wheel lock to lock several times while holding it on each lock to vacuum bleed the power steering system. Today, the battery has been charging all day and is not topping up, I'm thinking a quick trip to the auto parts store for a battery health check can't hurt at this point.Even after one or two starts the chugging got pretty bad and the volt meter indicated a drop to around 7 or 8 volts when it was chugging. 

I'll keep everyone posted and check out some of the other suggestions to try and knock out as many potential issues here as possible.


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## Droach6498 (Nov 1, 2020)

Did you install power steering? Im purchasing a 65 that doesnt have it so I am looking for tech data to help thats more detailed than the Restoration guide


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## 1967pontiac400 (Dec 10, 2020)

Droach6498 said:


> Did you install power steering? Im purchasing a 65 that doesnt have it so I am looking for tech data to help thats more detailed than the Restoration guide


I replaced an old leaking pump, happy to help with what I can but I susptect adding it to a non-power steering car is a much bigger job.


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## Droach6498 (Nov 1, 2020)

Me too. Thats why Im asking and searching. I do have the GTO Repoduction book iot doesnt say how to but it shows how its done, blowup. All parts right down to screws and nuts. Its a great book for referance.This is a 65 gto with a 67 Raim air 3 engine. Strange it doesnt have PS.


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## 64since65 (Dec 11, 2019)

OK, this isn't exactly an answer to the question in this thread but the issue reminded me of a problem I had years ago ('68/'69) with my '64 GTO when I was at General Motors Institute - in other words, there were lots of guys around that were into working on cars but nobody had an answer in this case. Hopefully some of you will enjoy the story and maybe even have an answer for why it happened. My roommate and I, along with a few other guys at school, never could make sense of it.

My car always started very easily hot or cold but one day it started having a problem where after driving long enough to get it up to a normal temperature (10-15 miles??) it wouldn't restart after a quick stop. The first time this happened I thought someone stole my battery because nothing worked - headlights, radio, interior lights, parking lights. It was like someone pulled the battery but the battery was still there and after about a 20 minute cool down the car started up just fine. This happened every time for about 2-3 months while we kept trying to find the problem. Since I could walk to classes and knew how to handle the problem, it wasn't a big deal but it was really annoying.

One day I wanted to stop at a corner store on my way home and decided to see if the starter would work so I put the car in neutral while going down a slight hill at about 50 MPH, shut off the engine and hit the starter. Nothing! So I put it in gear and let out the clutch to start the engine. No luck! There was apparently not even any juice to energize the alternator so no spark and the car just came to a stop in the middle of the road - just before dark of course and now with no lights! Luckily a passing motorist stopped and helped me push the car off the road. About twenty minutes later the car started just fine.

Eventually we replaced the regulator on a whim to see if that would solve the problem. It did! So I drove it a couple weeks with the new regulator not fully buttoned up to test it. Once I was convinced the problem was solved, I buttoned it up - AND THE PROBLEM CAME BACK! We went over what was different and the only thing we could figure out was that we didn't have the static suppression condenser installed during the 'test' period. So we took the condenser back off and the problem went away. Finally, I installed a new condenser and never had the problem again.

As far as we could see from looking at the electrical diagram, the regulator has nothing to do with the headlights so it shouldn't have caused an open circuit and if the condenser short circuited enough to drain the battery then it would have fried the wires. And everything worked without the condenser (other than static on the radio occasionally) so the condenser must have been shorting out when hot but we still couldn't see how that would kill everything including the headlights. So we never did figure out how that condenser could cause a _complete _loss of electrical power but it definitely did.


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## Droach6498 (Nov 1, 2020)

Sounds like a job for Superman! No really maybe an electrical engineer? I sure as hell dont know, ask me about building a house or a structure no problem, remodeling, but cars, all I know iof something goes wrong I find someone to fix it. Which leads to I need someone to install power steering in my 65 goat with manual, or a coach possibly.
Im currently watching a guy do it on youtube wow does he have a dirty mouth I thought mine was bad. Fukina.


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## mikelly2 (Nov 24, 2018)

Just wanted to add: I covered all the things PJ mentions but still had the same heat soak issue. I decided a mini starter would solve my problem. Being the cheapskate that I am I bought the Summit house brand. It had plenty clearance compared to the OEM and worked better but I still had the problem occasionally. I went round and round until I finally bought a Powermaster starter and never looked back...and yes I had to shim it.


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## Droach6498 (Nov 1, 2020)

mikelly2 said:


> Just wanted to add: I covered all the things PJ mentions but still had the same heat soak issue. I decided a mini starter would solve my problem. Being the cheapskate that I am I bought the Summit house brand. It had plenty clearance compared to the OEM and worked better but I still had the problem occasionally. I went round and round until I finally bought a Powermaster starter and never looked back...and yes I had to shim it.


That is exactl the same as what I did eccept I was offered a really good price for the car 5 years ago & sold it. I bought another yesterday, with a 400 & headers.


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## 1967pontiac400 (Dec 10, 2020)

Thanks everyone for you input. I ran every test and in the end, swapping in a new mini hi-torque starter did the trick. Starts right up hot now, thanks!


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