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shua57
07-28-2014, 04:57 AM
Quick back story.....1957 210 Sedan, ground up garage restoration by me, FI 350 TBI, 200R4 trans, 3.73 Explorer posi traction rear, EZ wiring 21 circuit harness, Autometer gauges and a bunch of custom stuff.
Problem that I thought I fixed:
1957 Chevy ignition switch drops power from ign when turned to start which causes ECM to loose power. Power is need to ECM and fuel pump relay to tell ECM to fire.

My previous solution:
Installed relay - constant power to relay, feed output power to ECM, relay activated by key switch.

Result:
relay fried (after a couple years trying to find the problem). Must have burnt the contacts up because when switch was in run power was backfeeding into relay. Now post 87 (power output) is not showing power during start. ECM is not getting power during cranking because the key switch on a 57 does what it does. For some reason AWW (I think) rebuilt the 55-56 switches so they supply power in both run and start but didn't do the 57's.

Solutions (aka ideas):
Option 1
What is I relayed the key switch? If I install a relay so as when in start mode I feed power back to the run mode.

Option 2:
Install a RFI keyless start kit. I could drop $400 on a kit that just detects when I'm getting close, unlocks my doors, disables the alarm and powers the push button start. Then just hop in and push the start button. Sounds like fun. Might try to just relay the thing till I get the 79 Camaro done.

Question:
Will using a relay to power Run while in start be a problem?
Josh

shua57
07-28-2014, 09:50 AM
Ha, finally a solution that I did not know exists. I got in touch with AAW and they already make a 57 switch that they sell in their kits that is bussed in crank and run. I gave up looking 4 years ago and just designed a work around that failed. New switch has been ordered. I'm excited.
Josh

chevynut
07-28-2014, 09:54 AM
Josh, I don't know what happened to cause your solution to fail but I don't understand what "power was 'backfeeding' into relay" means. Current runs one direction....from power to ground. I don't understand what the term "backfeeding" refers to.

This is not a new problem and anyone with an electronic ignition system has to deal with it. 55s and 56's have two terminals, "ign 1" and "ign 2" and you just tie them together to make it work. I am not familiar with how the 57 switch works but i do know the starter solenoid supplies power to the coil during cranking, bypassing the ballast resistor.

Do you know how others have solved this problem? Can't you just tie the "R" terminal on the starter and "ignition" terminal on the ignition switch together? All the solenoid is is a relay.

Rick_L
07-28-2014, 10:33 AM
I don't see how applying power to both power contacts on a relay "burns it up".

Seems to me that the relay was either defective, or it was not rated for the power it had to handle during cranking.

The "R" terminal on the started solenoid is functionally the same relay. I've never seen an R terminal contact burn up.

chevynut
07-28-2014, 11:24 AM
You don't need a new ignition switch, just tie the "IGN" terminal and the solenoid "R" terminal together. That will give you power in both run and start positions of the switch.

shua57
07-28-2014, 11:53 AM
Backfeeding is probably not the technical term but what was happening was I was using a 5 prong relay - #30(12V) #87a(12V) #85(ground) #86(switched) #87(output). I had #87 running to the power to the ECM and Fuel pump relay.Since the 57 switch brakes power from run when in crank, I was loosing power to the ECM during cranking, meaning no ECM, no injectors, etc. When I wired the relay in I now realize I wired it wrong but I digress. What was actually happening was during run the wire to the ECM had power which was feeding back into #87 (might of not burnt it up but I think it had something to do with it since I no longer can get 12V from the #87 terminal) but my intent was to feed power to the ECM through the relay.
What I should have done was do like Laszlo said but never even thought of it.
What is going to happen now is I will replace the stock key switch with the AAW switch (it's just the housing, not the tumbler). I may just try to feed power back from the R terminal and send the AAW switch back. Who knows.

Side note.....30 Amp relay, with what looked like acid corrosion around the terminals, car has not been out of garage in 4 years and relay is inside car.
Josh

shua57
07-29-2014, 06:41 AM
So no luck last night getting everything to work. When I jumped a wire across the SOL to the IGN car would crank in run. I think I will have to go back through my wiring harness and change a few things. Here is a picture of how my ignition switch pins out:
3278
Correct me if I'm wrong but doesn't turning the key from OFF to RUN power the IGN and turning the key to START powers just the SOL? If this is the case then I run a start wire from the S terminal on the starter (through the nuetral switch) to the SOL side of the ignition switch, 12v constant power to the BAT. Then the ECM, fuel pump relay, etc off the IGN???
This seems wrong because when I jumper the SOL and IGN, then I am giving power to the SOL while in RUN. This is why I relayed it in the first place, I got stuck here because it seems like I need a IGN2 set of prongs that would only power in the start position but would keep the power to IGN1 (aka bussed).

Brain meltinggggg
Josh

chevynut
07-29-2014, 07:43 AM
You can't jumper across the "sol" and "ign" terminals because it will do exactly what it did...crank in run. That's not what I suggested you do. You need to jumper the "ign" terminal and the "R" terminal from the solenoid together. The solenoid is just acting like the relay that you put there and supplies 12V while cranking.

Do you have anything on the "R" terminal of the solenoid now? If not, add a wire and connect it to the "ign" terminal or jumper it where you power your ECM.

shua57
07-29-2014, 08:17 AM
Ahh, I see what you are talking about, I was under the dash trying to wire it from memory of this conversation and well got my wires crossed...hehe. I didn't attach anything to the "R" post. It is a high torque mini-starter and I can't even remember what it looks like...lol. I'll give it a shot tonight. I appreciate the help.
Josh

shua57
07-29-2014, 08:26 AM
Another quick question if you don't mind, under my dash is a complete wiring mess do to the IDIDIT column, Autometer gauges, stereo, computer,etc...I want to clean it up. Has anyone used wire loom mesh? I love it when I'm building computers and it would be easier to flex than plastic loom. Of course I would have to disconnect all my wiring and run it through a mesh loom.
Josh

shua57
07-29-2014, 08:29 AM
OOOO....this is what I need:
http://www.quickcable.com/products.php?pageId=451
made of nylon and is split. Sweet!
Josh

shua57
07-29-2014, 02:49 PM
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
07-30-2014, 07:42 AM
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
07-30-2014, 08:11 AM
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
07-30-2014, 04:28 PM
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
07-30-2014, 05:43 PM
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
07-31-2014, 04:40 AM
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
07-31-2014, 07:30 AM
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
07-31-2014, 07:36 AM
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
07-31-2014, 08:38 AM
[QUOTE=chevynut;19440]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

shua57
07-31-2014, 08:46 AM
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.

I'll check voltage drop on battery tonight. I have a number of theories about what could be the problem such as ignition switch drops voltage to 9V during crank to IGN (which I could relay the IGN prongs to boost it back up to 12V), the mini starter may be draining to much voltage (but to just 9V???) or since my battery is in the trunk the 2/0 cable isn't carrying the required load or my battery could have went weak though I do all my testing with the battery charger hooked up.
Josh

shua57
07-31-2014, 03:37 PM
Voltage drop across battery during cranking was to 10V. Car fired almost immediately like it is suppose to. I may be out of gas but car did not stay running. Did it several times car would start, idle for various times then die. As long as I was feathering the gas it was fine. When it did idle it almost felt like a miss but was more like a stumble. I'm also not getting computer controlled idle adjustment at start up and braking. I get a flat idle whether it is freeze cold temps or hot. Something just isn't right.
Josh