Really weird Starting Problem

[Justin]

This is obviously a very common problem. Its easy to bypass by using the black/blue wire to trigger a relay to provide the solenoid direct power from the battery.

Its a bandaid and does not address the actual problem. To my knowledge no one has discovered the actual problem. I had to do this modification on my Supra that has a brand new wiring harness on it. I also have a brand new ignition harness (the 1 ft section between the key cylinder and the rest of the body harness)

 

[ForcedTorque]

This thread has almost convinced me to just do the bypass, although I hate a bandaid. Justin, your comments have come very close to pushing me off that ledge. BUT, not only do I have a starting problem, but something is draining my battery. I have been carrying the multimeter everywhere I go, and testing every time I have a problem. Most times, I have 12.5 - 12.8 volts with the car not running, but still not starting. The Neo usually shows 11.4 11.5. So, it may not be draining as bad as I had thought. Most of my driving is 2 miles or less, so I don't give it much time to be get much more than what I get. I guess I'll go look up that bypass thread.

 

[ZoomZoomZoom]

This is obviously a very common problem. Its easy to bypass by using the black/blue wire to trigger a relay to provide the solenoid direct power from the battery.

Its a bandaid and does not address the actual problem. To my knowledge no one has discovered the actual problem. I had to do this modification on my Supra that has a brand new wiring harness on it. I also have a brand new ignition harness (the 1 ft section between the key cylinder and the rest of the body harness)

No one has discovered the actual problem because there is not just one problem. There are combinations of problems that can create the same result - starter won't crank. So that's why I posted the solution to my car's issue, it might help someone else. I like troubleshooting, so the by-pass was not a solution for me, but a handy troubleshooting tool if needed.

 

[jetjock]

Yeah, no cranks are a huge mystery alright. Any possible failure of the starter circuit on an old car is totally beyond anyone's comprehension or the ability to effectively and intelligently troubleshoot. Maybe NASA could help. Nah, probably not. Time to break out the bag of chicken bones and eye of newt...

 

[ForcedTorque]

^OK, now I don't feel so bad. Going to buy a relay tomorrow when I pick up my new spark plugs. I hope that I don't still have a battery drain once I get it done, but I'm betting I do.

 

[Justin]

^OK, now I don't feel so bad. Going to buy a relay tomorrow when I pick up my new spark plugs. I hope that I don't still have a battery drain once I get it done, but I'm betting I do.

If you think there is a load on your battery then you should test that to confirm. No bypass/bandaid/trick is going to help start the car when there's not enough juice to do so

As mentioned earlier, disconnect the negative terminal then use a multimeter set to the 'current' setting to measure the draw. IIRC toyota recommends a .08 amp draw with the ignition off. That seems way high as both Supras I have tested measured .02.

 

[MKIII TURBO60-1]

ive been having the same problem, ive changed starters, wiggled wires, used a jump box and sometimes the jump box wont even work, i was thinking my starter might not be strong enough in torque cuz it gets stuck in the flywheel and i have to shake the car while in gear or turn the crank pulley to get it free, im going to try to replace the starter harness and see how that goes, wish me luck

 

[ZoomZoomZoom]

Yeah, no cranks are a huge mystery alright. Any possible failure of the starter circuit on an old car is totally beyond anyone's comprehension or the ability to effectively and intelligently troubleshoot. Maybe NASA could help. Nah, probably not. Time to break out the bag of chicken bones and eye of newt...

Are you getting old and crabby too??

:: IJ. ::

 

[Kckazdude]

It's not a problem with your battery.....<snip>

Not picking on you, just using your quote as you were the first one to post this.

My question is why in the hell anyone would think it a good idea to use a relay to trigger a relay in the starter circuit? Did anyone even think this one through? Seems to me it would be easier to perform a voltage drop test isolate the issue.

 

[ForcedTorque]

Two things changed today, and the car did great all day. 4 attempts, 4 starts.

1. I tightened the battery cables down good. They have been pretty snug, but not super tight, as I have been swapping batteries a lot.

2. The weather did not go down into the the mid twenties last night. I wore two jackets to work yesterday, and shorts today. I don't know if it is the starter or the wiring, but something must not like the cold. My guess is starter, but I'm gonna bypass the wiring anyway.

I just have one question on that bypass that I have not seen addressed. If you are powering the relay with wire off the starter how do you eliminate the bad wiring problem? OK...Second question, and one I haven't mentioned in the thread. I have tested the the wire going to the starter before this problem ever became an issue. It always showed 12V+.

 

[jetjock]

My question is why in the hell anyone would think it a good idea to use a relay to trigger a relay in the starter circuit? Did anyone even think this one through? Seems to me it would be easier to perform a voltage drop test isolate the issue.

Why indeed. In fact I thought I said that a few posts back. Used different words though

 

[Justin]

If you are powering the relay with wire off the starter how do you eliminate the bad wiring problem?

You don't, that's why its a bandaid. The relay takes miliamps to click over, the starter solenoid requires many amps to operate. Even with whatever the problem is, the relay will still click over, allowing the starter solenoid to operate as well.

 

[ForcedTorque]

thanks Justin!