Slow Cranking When Hot

[P.J. Romano]

We have this vendor advertising "Opel GT BOSCH Starter Relay Kit, Hard Start Cure" where he says:
"If your car is not responding (no click or very slow movement at starter) when engine is HOT and you are trying to start it...then you can fix this problem at your own by using this simple kit and save a big money."

This is exactly the problem that I have. When cold, starter will crank nicely. Once the engine is at the working temperature, especially after longer drive, the starter will crank very slowly or will turn a little and stop. After 5-10 minutes when it cools off, the starter will crank without problem. I have replaced the starter with the newly rebuilt one, replaced the contact switch at the steering wheel and installed Otto start kit. Still the same.

I do not see how is above starter relay kit any different from Otto start kit. So, what could be the problem?

[First opel 1981]

We have this vendor advertising "Opel GT BOSCH Starter Relay Kit, Hard Start Cure" where he says:
"If your car is not responding (no click or very slow movement at starter) when engine is HOT and you are trying to start it...then you can fix this problem at your own by using this simple kit and save a big money."

This is exactly the problem that I have. When cold, starter will crank nicely. Once the engine is at the working temperature, especially after longer drive, the starter will crank very slowly or will turn a little and stop. After 5-10 minutes when it cools off, the starter will crank without problem. I have replaced the starter with the newly rebuilt one, replaced the contact switch at the steering wheel and installed Otto start kit. Still the same.

I do not see how is above starter relay kit any different from Otto start kit. So, what could be the problem?

Has it always done this or is it a new condition?

[RallyBob]

I do not see how is above starter relay kit any different from Otto start kit. So, what could be the problem?

When was the last time you replaced the battery cables...if ever? They can corrode internally, which reduces conductivity. Heat only exaggerates the issue (more electrical resistance).

HTH,
Bob

[yellaopelgt]

Do a search on this issue.....there are a TON of suggestions. I will agree with Bob though....I had the same problem for YEARS and systematically going through the grounds etc. didnt help much. Then I finally realized all that was left to replace was the 35+ year old cables......VOILA....problem solved!! They looked perfectly fine on the outside,internally,they were GREEN!!!!
Joe

[P.J. Romano]

Has it always done this or is it a new condition?

This is condition since the restoration in 2007. Don’t know if it was the same before – car was not in a driving condition.

When was the last time you replaced the battery cables...if ever?
Bob

New cables, new battery, new cut-off switch, new 65A alternator. This car went through no money spared restoration (hope my wife is not reading this).

Do a search on this issue.....there are a TON of suggestions.
Joe

Couldn’t find any on this particular issue. Could you post the link? Thanks.


My last hope would be the engine ground cable. Will try to replace it later. Too cold now to work in the unheated garage. Thought that somebody experienced similar issue and will give me a magic tip. Man, it is embarrassing when you stop at gas station, everybody is looking at the attractive car and than it would not start!

[First opel 1981]

This is condition since the restoration in 2007. Don’t know if it was the same before – car was not in a driving condition.

I feel your pain about the not starting when everyone is looking. 1981 GT had the same problem. It would start perfect when cold but after being run, it wouldn't start at all. Being young and innocent I actually hooked up 2 batteries in series (yes, 24V) with the help of a Ford starter solenoid to operate with the flick of a switch for those emergency needs.

For the specs on the car. When I got it, the engine had just been rebuilt and had never been fired. I suspect the tightness of the engine contributed to the problem. With that engine, only, I had the problem. One day someone told me to change the thermostat. I put in a cooler thermostat and the problem was gone.

Over the years I have come up with a couple other possibilities to help this.
1) The cables (but that has been taken care of on yours)
2) Starter brushes (again, obviously not your issue)
3) Starter solenoid contacts. It's easy to overlook this one.
4) Use a synthetic oil. Less breakdown of viscosity at higher temps
5) Check the output on your alternator to insure it is appropriately charging your battery
6) Check the output on the battery and get one with higher CCA
7) Thermostat (covered that above)
8) NEVER put a pair of 12V batteries in series without isolating the rest of the electrical system away from the 12V you are supplying to the battery unless you want to replace every bulb in the car.

Or, you can just change the engine....~LOL~

[hrcollinsjr]

When cold, starter will crank nicely. Once the engine is at the working temperature, especially after longer drive, the starter will crank very slowly or will turn a little and stop. After 5-10 minutes when it cools off, the starter will crank without problem.

How much initial timing advance are you running? I'm assuming you are also running the higher compression pistons. If you’ve increased the timing advance and increased the CR , this could be your problem or at least part of it.

Harold

[hrcollinsjr]

Being young and innocent I actually hooked up 2 batteries in series (yes, 24V) with the help of a Ford starter solenoid to operate with the flick of a switch for those emergency needs.

8) NEVER put a pair of 12V batteries in series without isolating the rest of the electrical system away from the 12V you are supplying to the battery unless you want to replace every bulb in the car.

How about just wiring them parallel so you double [increase] the amps without increasing [doubling] your voltage or better yet figure the problem out and fix it. I've made my mistakes to with similar results. Adjusted a regulator and didn't test it before taking off somewhere. It's amazing how much those little alternators can put out when they aren't regulated.

Harold

[P.J. Romano]

How much initial timing advance are you running? I'm assuming you are also running the higher compression pistons. If you’ve increased the timing advance and increased the CR , this could be your problem or at least part of it.

Harold

Harold, I never thought that way but you might be spot on money here. I am running electronic ignition, 1.9l engine, DSD Webers and Combination cam. I adjusted the timing "by ear" and the car runs well. Let me retard the timing a bit and see if this will help cranking. Unfortunately with a huge amount of snow this winter, this will have to wait until the roads dry out.

[BQS4]

We have this vendor advertising "Opel GT BOSCH Starter Relay Kit, Hard Start Cure" where he says:
"If your car is not responding (no click or very slow movement at starter) when engine is HOT and you are trying to start it...then you can fix this problem at your own by using this simple kit and save a big money."

This is exactly the problem that I have. When cold, starter will crank nicely. Once the engine is at the working temperature, especially after longer drive, the starter will crank very slowly or will turn a little and stop. After 5-10 minutes when it cools off, the starter will crank without problem. I have replaced the starter with the newly rebuilt one, replaced the contact switch at the steering wheel and installed Otto start kit. Still the same.

I do not see how is above starter relay kit any different from Otto start kit. So, what could be the problem?

My Sportwagon was doing the same thing, when cold, it would start right up, but, when I drove it home, got out to move my mom's car, got back in a minute later, would not start. Wait 10 minutes and it'd fire right up. Turned out to be the ground strap was not attached at one end. attached both ends properly and no more problems....

[gtblast]

Did you rebuild the engine and if so, how long ago and how many miles ago? If it was a tight rebuild with only a few miles since, it may just be tight when hot and will loosen up with the more miles you put on it. Believe it or not, I had this happen once in a a car I built up tight. I finished it up one evening, and then that night I drove it from DC to Jacksonville, Florida without shutting it off, and it was still tight enough when I got there, that I had to wait for it to cool some before restarting. After a few more hundred miles, it began to loosen up some.

[P.J. Romano]

Did you rebuild the engine and if so, how long ago and how many miles ago?

Still original engine, approx. 45000 miles. I am preparing 2.0 l engine though.

Much good advice. Eliminated battery, battery cables, ignition switch, starter. I feel that I should focus on:
- Engine ground strap
- Timing (I have the gut feeling that this is it)

Will post the outcome as soon as I put hands on my GT, weather permitting.

[yellaopelgt]

The timing should really have nothing to do with the hot start problem(other than getting it to fire quicker IMO,I got my car to fire instantly when I dialed it in) Its an electrical issue, especially since its an older/broken in motor. IF I understand his question directly,it starts fine....but creeps over slowly when HOT. Grounds. grounds. grounds..
Expansion on wires can be tricky...
put a meter on the starter when at cold start up...then at hot not wanting to start mode...That should give you direction

[First opel 1981]

How about just wiring them parallel so you increase the amps with doubling your voltage or better yet figure the problem out and fix it. I've made my mistakes to with similar results. Adjusted a regulator and didn't test it before taking off somewhere. It's amazing how much those little alternators can put out when they aren't regulated.

Harold

Hey, what can I say? I was only 17 at the time. I will tell ya though, that sucker cranked over faster than you could imagine at 24V.

[P.J. Romano]

put a meter on the starter when at cold start up...then at hot not wanting to start mode...That should give you direction

Thanks, good tip as well.

[RallyBob]

The timing should really have nothing to do with the hot start problem(other than geting it to fire quicker IMO,I got my car to fire intsantly when I dialed it in)

But overly advanced timing will make an engine crank over slowly. And a hot engine is affected even more. It's a possibility.

[P.J. Romano]

Nice, warm day today, so I had a chance to recreate the slow cranking condition. Yes, the problem was still there, despite new ground cable for the engine. So, there was the last option left: retard the timing. Guess what, the problem is gone!
Harold, Bob, you were right. Thank you.

The Compufire will be installed tomorrow but this is the whole new story...