Non starting issue back along with headlights not going up.

[1989 406]

I was having starting issues a few weeks back and thought I had the problem fixed. I put a new starter, battery and heat shield around the starter. I now go out in the morning and drive the car and it is fine until I turn it off. If I go to turn it off and try to start it again, it cranks very slowly and then does not start. If I let the car sit for a while, it starts right up. I am not sure where to go at this point. Obviously something heat related is the issue, that is why I put the heat shield on the starter.

While starting it up tonight after it cooled down, the car was running and I decided to put on the headlights and they are only opening up half now. I am guessing the motor is on the way out. Is there anything else I should check for. At this point I do not even know where the headlight motor is.

Thanks.

 

[John Robinson]

I would guess that you have a ground problem. You need to check the grounds on the frame rail on each side of the engine. There should be four of them. The two front grounds are for the headlights horn etc up front. Then there are two grounds (If it is like my 93 behind the battery). You will have to remove the battery to get to them. Next there should be several wires grounded to the bell housing on the drivers side. You will have to get them from below. I believe this group of grounds contains the ground for the starter. I am not an electrical engineer but I would think that if the starter was not getting a good ground it would not want to function when hot. Maybe someone else with more knowledge and a schematic for your year car can chime in. In my experience with the wiring systems for the c4 I have found that several different systems are controlled by the ECM through ground bundles. For that reason do not discount the headlights and the starter being interconnected.

 

[John Robinson]

The new starter you put in was it a heavy duty model for a 406 engine. I mentioned this in your first thread. Think about it when the engine is cold the starter is turning it over with the cylinders purged of compression but when it is hot the starter is then trying to turn over the engine against some of the cylinders being under compression.

Sorry to keep beating the same drum but If it were my car these are the things I would be looking at.

 

[boomdriver]

if thats a 406 motor....I'd expect the stock starter to drag and die...weekly.

hi-torque mini. And loose the heat wrap...thats like wrapping a hot branding iron in a blanket. a real heat shield would be a metal shield/plate that deflects radiated heat, not a wrap that holds heat.

headlites....coincidence..Motors wear out everyday. Easy rebuild.

 

[gmjunkie]

My guess is that John Robinson is correct on the grounds!~!!
Specially on the ones behind the battery and the ones on the bell housing!!! The strap from the frame to bell housing is a woven copper wire and has a tendency to corrode badly and turn green from heat and corrosion!~!! Clean the GROUNDS,ALL of them!~! High Resistance and Non-Existent GROUNDS make electronics do weird Sh*t!~!!!

 

[boomdriver]

My guess is that John Robinson is correct on the grounds!~!!
Specially on the ones behind the battery and the ones on the bell housing!!! The strap from the frame to bell housing is a woven copper wire and has a tendency to corrode badly and turn green from heat and corrosion!~!! Clean the GROUNDS,ALL of them!~! High Resistance and Non-Existent GROUNDS make electronics do weird Sh*t!~!!!

Regarding the grounds...

Knowing how sensitve these cars are to ground issues, being a plastic car, I cleaned up the natural grounds(GM) and added a cable from battery neg to the block on an ex stud, and a wire from battery to frame. The dual-post type battery is perfect for this. The top post is a direct path to frame/block.

 

[joe paco]

both head light motors failing at the same time, same failure mode? not likely a motor(s) problem.
from my memory the starter grounds to the block via the two mtg bolts. IF the main battery grnd cable is grounded to block, all things grounded so should be ok.
light motors ground to chassis, different ground wires.

start problem sounds like a voltage/current flow issue, battery drained below about 11 vdc. or the neg bat cable/eyelet is corroded. or, something seizing the engine...

no idea how both headlights can fail the same exact time, same way, esp with engine running, supposedly charging. Recently had some start issues with my '91, both headlights behaved erratically when battery voltage dropped below about 10 volts, relays chattering, motor mechanisms clicking, etc.

that issue was dead cell in battery.

also had a horn issue, cleaned four grounds, incl 2 under battery mounting tray. all were ok, grounding thru the two coats of black chassis paint via nibs under the terminal, as all of them are. I guess a shortcut would be to use a trouble light and touch each eyelet, but didn't have one at the time.

I'm always interested in these problems, 'cause we all are due!
joe

 

[1989 406]

The new starter you put in was it a heavy duty model for a 406 engine. I mentioned this in your first thread. Think about it when the engine is cold the starter is turning it over with the cylinders purged of compression but when it is hot the starter is then trying to turn over the engine against some of the cylinders being under compression.

Sorry to keep beating the same drum but If it were my car these are the things I would be looking at.

It is a general reman for a Vette. I spoke with some techs and they said that was all that it needed. I had thought as you did, that it would need a more powerful starter but I am not sure at this point because when it is cool it will start right up. After driving it a while it does not want to start again until it cools down.

 

[John Robinson]

It is a general reman for a Vette. I spoke with some techs and they said that was all that it needed. I had thought as you did, that it would need a more powerful starter but I am not sure at this point because when it is cool it will start right up. After driving it a while it does not want to start again until it cools down.

Also because the cylinders are hot the min. a fresh charge is put into them the heat makes it expand. so when you hit the starter it is coming up against super heated air and it will take a lot more starter to overcome that.