4 year electrical issue

[shua57]

OOOO....this is what I need:
http://www.quickcable.com/products.php?pageId=451
made of nylon and is split. Sweet!
Josh

[shua57]

Yep no "R" post. Must have been why I wire it like I did. I'll come up with something or just use AAW's switch.
Josh

[chevynut]

If there is no "R" post you can just use a relay, like you did before. Connect the "sol" wire from the ignition switch to the coil of the relay. Connect the switched terminals to the battery and load. It should only be activated while cranking. Just make sure it can handle the current you need to run your ECM and whatever else you connect to it.

[shua57]

That is my plan Laszlo. I will use a 5 prong relay (has 87a), take my current 12V power to the switch and attach to #30, the attach 87a to the BAT side of my ignition switch, come off th IGN side of my ignition switch to #86, run #87 back to the IGN side and then ground #85. I wonder though, when I do this, could I possibly over load the circuit while in start mode? I have my radio, ECM and maybe a few other things powering in RUN....shouldn't bother it.
Josh

[shua57]

Went and bought a relay after work. Figured I would check to make sure I was losing power to the fuel pump relay, had to wire a few things back up, but for some reason I'm getting power to the ECM and fuel pump relay during cranking. It does drop to 9V though. I tried it multiple times an even tested back at the switch. I thought the 57 switches didn't have power in IGN during cranking. Not true?
I guess the true test would be to unhook the oil pressure switch and see if it fires?
Josh

[Rick_L]

I thought the 57 switches didn't have power in IGN during cranking.

That was what I was told recently by someone I trust but that could be wrong. It actually makes more sense for it to have power in both positions.

It's easy enough to check.

If the IGN terminal had power in both run and start, then you'd have reduced voltage to the ignition (because the power would always go through the ballast resistor). The problems start when you don't need the ballast resistor any more.

[shua57]

Rick do you think a voltage drop of that magnitude will cause issues for the ECM?

What about using the relay that I don't need to create a redundant 12v to the ECM?

Or would going ahead with installing the relay to provide 12V to the IGN during cranking?

A little info as to how it is wired right now. "S" terminal on starter is powered off the SOL on the switch, IGN has the ECM, fuel pump relay, and some other things that I can't remember right now (I need to go back through and check all this, I have a 12V ignition wire running to the IGN that I can't remember why).
I'm not sure a ECM can take a voltage drop like that and not sure if the ignition switch or something else is draining that much voltage.
What I do know is that I metered the IGN prong while cranking and it dropped down to 9V, this makes since since I am only getting 9V at the ECM and fuel pump relay which is feed off the IGN. I do have 12v+ in IGN when in run. What is odd id that it drops to just 9V, like the circuit is has a resistor in it when in the crank mode.
I may be way over thinking this but I don't think the ECM likes not having 12V.
As far as the car actually starting, first attempt after sitting for a day is a little slow because it doesn't start till oil pressure hits 20psi. After the first start it starts faster as the oil pressure builds up quicker. This main reason for my revisiting this problem is because the fuel pump relay is suppose to be the first signal to the ECM to start the car and the oil pressure switch is suppose to be the secondary or the backup. If the fuel pump relay fails the car won't start till the ECM sees 20 psi which is what is happening.
Josh

[chevynut]

for some reason I'm getting power to the ECM and fuel pump relay during cranking.

I thought that's what you were trying to do.

It does drop to 9V though.

The voltage drop indicates you have a high resistance in the circuit. How much current will your relay handle?

Why did you connect the IGN side of the switch to the relay? You don't need a relay in the run mode, as everything should go through the switch.

[chevynut]

What I do know is that I metered the IGN prong while cranking and it dropped down to 9V, this makes since since I am only getting 9V at the ECM and fuel pump relay which is feed off the IGN.

What is the voltage at the "BAT" terminal while cranking? If it stays at 12V, the problem is your ignition switch can't handle the current needed for the ECM. You might need a relay in the "RUN" mode too. If the BAT terminal drops to 9V as well, your problem is between the ignition switch and battery. If the battery drops to 9V while cranking, you have a bad battery.

[shua57]

[QUOTE]

I thought that's what you were trying to do.

Yes that is what I am trying to do. Prior to yesterday this was not happening with the stock switch, therefor the relay setup. It is highly possible I did not have the wiring correct and since I have a desire to actually fix the slow starting issue, I may have switched some wires around as it should have been

Why did you connect the IGN side of the switch to the relay? You don't need a relay in the run mode, as everything should go through the switch

The relay is not currently hooked up. I'm not sure why it is working without the relay as I was almost positive the ignition switch was not giving me power to the ECM during cranking and for some reason it is now. This is bringing back memories of studying current calculations in physics....lol
Josh