Question about 1985 Ford Mustang

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Old style starter relay wiring

This is in a dirt track car , where we are using a key switch to simply power everything. The rest is a toggle/push button set up. My question is this...on an old style solenoid/relay, which is what we are currently running, what is the friggin "I" post used for? I know that my push button goes to the "S", and I have my coil powered of off its own toggle, but what is the purpose of the "I" post on the relay?, is this for and older application?, maybe a points ignition?

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Normally on the old style starter solenoid/relay you have two large bolts for the battery and starter cables to attach to. There are two other smaller bolts that are used for the starter actuation. The "I" is used to add voltage to the points so the engine will start while the solenoid is in the start position, the other "S" goes to the start button or start side of the ignition switch. Old style ignitions used to drop the voltage to the coil during start and the engine would turn and turn until the key was released and then the engine would catch and start. To cure this they made the solenoids were designed to give temp power to the ignition system when cranking and starting. Hope this helps, RAC

Posted on Apr 13, 2009

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The I is ignition usually this runs from the ignition switch to the solonoid which in turn activates the solonoid and kicks it in to power up the starter.

Posted on Apr 13, 2009

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We need the schematics, to also put toggle switch for starting

Fitting a toggle switch for starting used to be a budget method of overcoming starter switch and other problems on older cars but will not work where the standard ignition key contains a transponder.

You haven't provided enough detail for a good answer but wiring a (spring return type) toggle switch to operate the starter motor is relatively easy and requires only a battery live and a wire to the starter solenoid or to the coil of the starter relay if you wish to use a relay.
Mostly these wires can be extended from the existing harness to the new switch.

Apr 19, 2015 | Cars & Trucks

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94ford probe won't start

Well Sandra , the thing to do would be to get it to turn the engine over with the key , Then diagnose the no start problem . Look at a wiring diagram (do you know what that is ?) When you turn the key to start , the electrical part of the ignition switch sends B+ voltage to the starter interrupter relay through the clutch switch to the starter motor solenoid . Testing the electrical circuit with a DVOM - digital volt ohm meter with the help of a wiring diagram ,so you know where to test is the proper way to diagnose the problem . Not guessing ,an rigging the stuff . You can find free wiring diagrams here
Enter vehicle info. year , make , model an engine ! Under system click on engine ,then under subsystem click starting . Click the search button then the third blue link .
Electric Testing Techniques You Need to Know
Do you know what a relay is ?
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If you look at the wiring diagram you will see the relay is controlled by the CPU - engine computer .
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I have a 1982 dodge ram w150 318 4 speed when i turn the key i lose everything let me start from the beginning my truck started up then died then when I went to restart I heard a thunk then nothing last...

What happens when you turn the key to on? Do the warning lights and gauges come on? Turning the key to start, do the lights and gauges stay on? Just nothing at the starter?

Or does power just shut off when you turn the key to start, everything goes out, no warning lights or gauges? Then check cables, battery terminals, grounds for clean tight connections. There is a problem between the battery and the ignition switch.

If the switch still receives and sends power out (to the dash, for one) but start circuit is not working (from battery to ignition switch to clutch switch to starter relay to starter solenoid to starter to ground-and back to battery), then here's where we at: with key off, use a small screwdriver and short the big cable at starter to the starter solenoid small wire connection, or use a small jumper wire to do the same-battery cable at starter to the small wire connection on the starter solenoid. Starter motor should spin and crank engine. Does it? If so, start checking the start wire out of ignition switch for power when key is held in start. If you have a clutch switch, check for power in with key in start. Should have battery voltage to the clutch switch with key held in start. Keep checking the start wire along the start circuit. Not sure how the start relay is wired into the circuit, would have to see a diagram, but if you pull the relay out and use a test light or multi meter, could check for power on the terminals where relay plugs in. Key off, should have one terminal that is hot. With key held in start, at least one other terminal should also be hot. This would be the start wire out of ignition switch sending a signal to the relay.
Good luck, hope you find it. Sorry I don't have a wiring diagram to help you more.

Aug 30, 2013 | 2000 Dodge Caravan

1 Answer

I have 93 dodge power ram and it wont start it has power to the starter but not any where else even with the key in the on position

ignition or starter relay should be checked first.
Faulty ignition switch might be an issue.
You will still need an ignition source before you think about the push button start.
A friend has the same problem, and its a computer issue. (underhood, pass side low on firewall)
best of luck to ya.

Dec 10, 2012 | 1993 Dodge Ram 250

1 Answer

Won't start

So it's a no crank condition? Do dash lights, gauges, and everything else work when the car won't crank over? If so, buy a cheap $5.00 testlight, and when the car won't crank, pull the small black wire off the starter solenoid. While someone holds the key in start (cranking) position and clutch pedal depressed, see if the black wire has power as it should. (Ground the testlight and just touch the wire's end terminal. If powered, the testlight will light up.) If power there, then the starter solenoid is failing. Toyota starters are very good units, but the solenoid's internal contacts get old and pitted.
If no power at the black wire, then the start circuit from ignition switch to clutch safety switch (on the clutch pedal) to starter relay to starter solenoid will have to be diagnosed. To double-check: take a single battery jumper cable and put it on the positive battery post connection. Put the other end of the jumper cable on the solenoid terminal where black wire was removed. Key can be off. Make sure car is in neutral, brake set. If starter now operates, solenoid is O.K., and it is a problem in the start circuit, -ignition switch, neutral start switch, or in the wiring.
Now find a grounding place for testlight under the dash. When car won't crank, check for power coming out of ignition switch on the black wire with white stripe. This is the start wire for the starter solenoid. Key must be in crank position. Wire shoud be powered-ignition switch is working. If no power, switch is failing. You can do the same for the clutch start switch-it's a simple switch, that when clutch is depressed switch is closed and passes power on from ignition switch to the starter relay (thus allowing power to the starter solenoid). Black wire, red stripe-this is wire from clutch switch to starter relay. When key is in crank, clutch depressed, this wire should be hot.
With me so far? Still haven't found a problem, or any loose connections? Next and last is the starter relay. It is located under dash, close to gas pedal, but under the center console, just forward and left of gear shifter. It can be tested and the wiring diagnosed there, but relays are cheap, so just swap in another and see if that helps.
If you have tried everything, and still no help, you could try a new wire from the relay to the starter solenoid. This is that black wire we started with. Older toyotas sometimes have a problem with degraded wiring not passing enough current to operate the starter

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1 Answer

2nd Accessory Power??? Push button Ignition

like your style but a simple dash mounted old fashioned ignition lock would do the trick then a padlock and chain .if no key chip is used on this vehicle that is ,if so then a hook to hold the key next to the original lock so the transponder can pick it up.All these relays and things are more to go wrong at a later date and not necessary ,Whatever you do make sure the steering lock mechanism is removed so it cannot lock the steering up when turning ,their is only three main cables to worry about power feed -feed to ignition and starter motor hence in the old films they join the wires up to steal a car bit more copmplicated on a modern car with a chipped key it just doesnt happen,a breakdonw pick up truck is used to lift a vehicle and nobody bats an eyelid ,then scrapyard for all the bits to make it run again .Now i know nothing about this but when the shunter driver has lost the key to customers car on the airport parking service -say no more

Feb 07, 2012 | Chevrolet Cavalier Cars & Trucks

2 Answers

Car will not try to turn over using key but will start if push started. have already replaced starter

If the new starter is no better than the old starter, I would still consider removing and having the starter tested on a bench to see if it is functioning correctly. Check the connections from the battery to the starter to make sure the cable in between is not causing this problem.

The fact that push starting the car will start it, tells me the ignition and fuel systems are ok. It's a possible bad starter again if the wiring is alright.

Good luck on this repair.

Jan 14, 2011 | 1994 Acura Integra

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Is there anyway to hard wire my ignition in my 1989 camaro rs

Sure. Not sure what you mean by "hard wire", but if you don't like the ecu control over the timing and spark advance, you can simply revert to distributer that either has points or a self contained electronic ignition that uses a standard coil. One way to do that is to buy a distributer for a boat that uses the same engine. Marine applications don't use a separate ecu, so all you need is a marine distributer and an ignition coil. Cost about $275. I have done it many times when the whole ecu, harness, etc., is too much of a mess to work with.

If you are speaking of the ignition switch, that is also easy. You can just buy a universal ignition switch for $5 and run the basic power, ignition, starter, and accessory wires to that.

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1 Answer

I need a simple diagram on how to install a push button starter switch using a toggle switch, push button and resistor. The only thing I need is to start the car. Its an old VW and I want to bypass the...

its hard to provide a schmatic without pictures but here is what you would need ... i assume you are using a three position toggle switch with a spring loaded position for start ... all contacts would be off at first .. contact #1 would be off, on , on ... that would switch 12 volts to the ignittion ballast resistor that is in series with the coil (normal running position).. contact #2 would be off, off, on (spring loaded) ... that would jumper the ballast resistor only for starting (that compensates for normally low battery voltage while running the starter) .... the third contact would also be off, off, on (spring loaded) . that would cnnect 12 volts to the starter relay .. that contact would have to be rated for the current drawn by the starter relay .... if you wanted a different switch arrangment a toggle switch for ignition and a seperate push button for start .. then the ignition toggle would just provide 12 volts to the balast resistor that is in series with the coil ... it would only need one contact off,on .. the push button would have to have two contacts both operate at the same time .. one conntact would jump the balast resistor when on (start) .. the second would provide 12volts to the starter relay.. the second switch configuration might be easier to find than the first ...

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93 mustang 2.3 liter starter relay wiring

This may help.A relay is just a switch that's used to isolate a control circuits power source from the device's that it's being used to switch.On motor vehicles the relay is genarally grounded to the chassis and all you need to supply is a positive lead to turn it on.Here's a quick schematic,The negative is to the chassis,the positive leads need to be kept on separate circuits,but note the relay can switch either direction.f7e76fd.png

Apr 13, 2009 | 1985 Ford Mustang

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