hitmanpty

iam away from the car now. But like to know more. What this will test tell me. Can you explaing a little more

hitmanpty

I getting frustraded with this ignition problem. It come to mind. Just to run a new wire direct from yellow wire to starter motor and be done .

No that is stuped idea. Dont want to do that realy

rodj

From the formula;
more resistance in circuit = lower voltage.

Bad /dirty connections will have hi resistance; hence the reason to test resistance on the wiring to starter

Easy test would be as you say to run a new wire from key to starter

3D87C4

When the yellow wire is disconnected no current is flowing so there won't be any voltage drop.

When you connect the yellow and green wires current flows and the voltage drops.

If the battery voltage isn't changing (please check this) then there is a 12.5v-11.6v=0.9v drop due to the resistance of the wires and ignition switch. I'm not sure that's enough to cause a problem.

With the yellow and green wires connected have you checked the voltage at other points in the circuit?

The most important place to measure would be at the solenoid itself: What voltage do you get at the purple wire when it is disconnected from the solenoid? What voltage do you get when it is connected?

Similarly, what voltages do you get when you probe at the transmission position switch, connected and disconnected?



Running a wire from the yellow wire to the solenoid would work but would eliminate the transmission position switch (a safety feature).

hitmanpty

Ok i will have to get back to the car and do all this test you are talking about. Unfortunately. I can only work in the car on weekends. I will try to go to my car some time during the week

Let sayi get low voltage on the starter after i do the test. What this de meenig of that

hitmanpty

Runnig a wire directly from yelow wire to starter will also disable the cool stard inje tor

oldalaskaman

then you buy a prom from a 89 vette and plug the cold start injector, car will start better

hitmanpty

I was reading about voltage drop test for the starter system. I find out there is a couple of test i have to do. The problem can be resistance on wire some where. May be on battery wire. Will do test first

3D87C4

By checking the voltage drop at various points along the circuit you learn where the high resistance section is---and that's the place you'll need to fix.

Sorry, this will take some math to explain:

The voltages should add up:

Let

Vsol= the voltage between the solenoid and ground
Vtran= the voltage between the transmission switch and ground
Vrel= the voltage between the start enable relay (the yellow & green wire) and ground
Vbat= the battery voltage

then

Vbat=Vsol + (Vtrans - Vsol) + (Vrel-Vtrans) + (Vbat-Vrel)

Right now, you know (Vbat-Vrel)=12.5-11.6=0.9v which is the voltage drop due to the ignition switch and wiring.

loaded vet

I had the same symptoms with my 87 and finally found the ignition switch was bad on the starter contacts inside the switch. My switch was the original unit so I replaced it with a new one and the problem went away. I have had no startup problem since replacing the ignition switch. Should you decide to replace the ignition switch, take your time and pay attention to the details coming apart and back together.

Gary

oldalaskaman

I vote this one

hitmanpty

yesterday. I pull out of the internet. a guia to test drop voltage on the starter system. it tell me what point sure I take measurements I will be preforming this varios test point. including yours this weekend.

hitmanpty

sound like a logical idea. but before I go and start changing part. is there any test I can do to the ignition switch. to find out of it is bad??? I all ready going to do some drop volt test on saturday. it will be a good idea if someone can tell me how to check this ignition switch

thank you for the sugestion

3D87C4

If the voltage drop is largest between the battery and relay then the ignition switch is suspect.

As an experiment you could try a wire (and switch) from the battery to the green wire. If that starts your car every time and the normal connection (yellow wire to green wire) doesn't then, again, your ignition switch or wiring is suspect.

AGENT 86

If your testing with solenoid connected, your going to see a voltage drop due to load at solenoid. Is this the case ?

hitmanpty

Yes solenoid is connected to the trigger wire

hitmanpty

Good idea. I will try that also on saturday. To bad i true away my old push buttom cable. I will get a new one tomorrow

3D87C4

I suspect you're learning why the previous owner installed that button in the first place.

Check the voltage at various points in the circuit & you should find the problem.

hitmanpty

I all ready have good voltimeter, also some extantion cables I got for the voltimeter. since some of the test I will do involve go from the battery to the starter. and every body knows the distance of the 2.

also just when out I got my self a cable. to try to connect battery to green and white wire.

here is a link of some of the test I will do. in case someone need to do some test also.

http://www.aa1car.com/library/voltage_drop_testing.htm

hitmanpty

Yes now I know why the use the old trick. push buttom cable.

but not me. I will finish this the right way.