86 GN won't crank when hot - starter good.

T

Tom Kelly

Active Member
Joined
Jun 23, 2016
Having an issue with my 86 GN - Equipped with kill switch and viper alarm system installed by original owner in 1991. (Might be relevant) Battery in great shape (Optima battery) When car is hot and has not had a chance to cool down (at least an hour) won't crank. Installed a direct line to starter as emergency start until this is resolved. Starts right away using that direct line. So it's not the battery and not the starter. My mechanic suspects a possible failed (or failing) relay used by one of the two security systems even though they are under dash and not exposed to engine heat. And so we will be trying to track this down but wondering if anyone has experience with this problem. It might save us some diagnostic time if someone else has same experience and a solution.
Thanks
Tom
 
The first thing I would do is try another battery.

This summer I have had 3 GN's with Optima batteries that checked good, but would not start the car.

The most recent one today after the POS was on the charger for 2 days, it is now in the junk pile?
 
GN Bob said:
Hot start problems

I have the same problem with an Autozone rebuilt starter.
If I had a few extra bucks at the time, I would have gotten the mini starter offered on this site instead.

I think our problem is due to heat soaking of the starter solenoid.

Once you stop moving, the starter cooks from all the heat coming from the exhaust crossover and the solenoid binds up and won't close the contacts to send power to the starter motor.

Its a fairly easy fix to install a remote starter solenoid to hopefully eliminate this problem. I got my kit from Summit for about $25 - $30.

Since you changed your starter once before you know how to do the first half of the job already. Solder all connections and run a new 0 guage cable from the new solenoid to the starter.
Click to expand...


Sent from my iPhone using Tapatalk
 
I don't think it can be the starter or solenoid or battery as it will start if I make a direct connection to the starter, That is why we are suspecting that perhaps a relay designed to shut off the connection (kill switch or alarm) is taking its time resetting when hot.
 
If the alarm breaks the starter signal it may be a bad relay or a bad connection.

Time to get out the test light.
 
TurboBuRick said:
If the alarm breaks the starter signal it may be a bad relay or a bad connection.

Time to get out the test light.
Click to expand...
Yup. That is our conclusion as well. The one thing that doesn't make sense is why it only happens when engine is hot. Relays are all safely tucked up under dash and not near engine heat. Oh well, I am sure we will figure it out. thanks all for your input.
 
First check the battery cable, if the ends, normally the end attached to the starter, if it is corroded. It will act like a power resister when heated. After cooling it will allow the current to pass thru again allowing the starter to function.
 
A voltage drop test on the solenoid circuit would be a good idea after you do a good load test on the battery. Positive voltmeter lead on the battery and negative on the solenoid start terminal, then crank the engine. Try to do it when the engine is hot and will not start. 1/2 volt drop from battery voltage is acceptable. GM always had hot no start problems in the 80's. Weaker solenoid return springs were one solution they came up with to let the solenoid engage easier. Any resistance in the circuit will be worse when the engine is hot. Power has to go through the ignition and neutral switches on it's way to the solenoid. Not sure if your alarm system will cause it.
 
TurboBuRick said:
If the alarm breaks the starter signal it may be a bad relay or a bad connection.

Time to get out the test light.
Click to expand...
Yup. That is our conclusion as well. The one thing that doesn't make sense is why it only happens when engine is hot. Relays are all safely tucked up under dash and not near engine heat. Oh well, I am sure we will figure it out. thanks all for your input.
ek02 said:
A voltage drop test on the solenoid circuit would be a good idea after you do a good load test on the battery. Positive voltmeter lead on the battery and negative on the solenoid start terminal, then crank the engine. Try to do it when the engine is hot and will not start. 1/2 volt drop from battery voltage is acceptable. GM always had hot no start problems in the 80's. Weaker solenoid return springs were one solution they came up with to let the solenoid engage easier. Any resistance in the circuit will be worse when the engine is hot. Power has to go through the ignition and neutral switches on it's way to the solenoid. Not sure if your alarm system will cause it.
Click to expand...
Thanks but the thing is when the car won't start, I have a wire to the starter and I just connect it to the old harness from the electric brake which still has live 12 volts and the car fires right up. So I don't think it's starter or battery related. The cutout circuits of the two security systems are a more likely culprit I think.
 
When you jump from a 12 volt source directly to the solenoid, you are bypassing the entire circuit. Somewhere that circuit is dropping voltage due to high resistance when hot. The resistance can be in the wiring or even in the solenoid itself. If there is only .5 volt or less drop, the solenoid could be your problem. I would disable and bypass the alarm system if you can to eliminate it as the cause. I hope you solve the problem. I have dealt with this issue many times on GM vehicles, and it is frustrating.
 
You've been doing a lot of thinking, but not listening. Don't mean to sound like a dick, but you have already been given the answers several times here. If you can't take advice, why ask?

Elky.
 
sounds like a bad relay. when the relay gets hot it stops working. eventually your relay will fail and it wont start cold
 
SHADOWII said:
First check the battery cable, if the ends, normally the end attached to the starter, if it is corroded. It will act like a power resister when heated. After cooling it will allow the current to pass thru again allowing the starter to function.
Click to expand...
I vote for this one.
 
Actually I HAVE been listening to everyone's advice and appreciate all of the comments. I am a big believer in troubleshooting in a way than minimizes backtracking and so I think the best way to proceed is to return the car to original format (I.e. bypass the security systems and start the car with the key as new. If that solves the problem then I can eliminate battery, solenoid, starter, wiring, etc. and concentrate on security systems and their relays. However, If the problem continues then I can focus on the more normal issues like battery, solenoid, etc. In any event, leaving Sunday for sunny Italy for my annual trip there. I will deal with this when I return late August and of course post my findings. Thanks again to all.
 
Probably less likely but you might also want to check the ignition switch located I believe at the base of the steering column. Turning the key at the wheel moves a push rod within the column that actuates the switch located at the base of the steering column. This is what sends power to the starter solenoid that is on the starter and heat soaks from the crossover pipe.
 
hi all. Well I am back from Italy and feeling refreshed. Here is on update on my intermittent starting problem. I removed all vestiges of aftermarket kill switches and alarms and set it up as Buick intended; a direct connection from key to switch to starter. All is well again in Turboland. No problems starting. Thanks to all for your advice. I decided I don't really need all that fancy security system as the car is garaged or in my sight all the time
 
You must log in or register to reply here.

Similar threads

F
Transmission crappy when hot...
Replies
12
Views
2K
WE4
WE4
WE4
Strengthening the 2004R - 2nd Attempt
Replies
1
Views
3K
REDS HOT AIR
R
Top