Mustang Forum

Technical & General Discussion Area => Tech Torque Pre 1973 => Topic started by: Gabs64 on November 13, 2020, 09:49:39 PM

Title: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 13, 2020, 09:49:39 PM
Hi All first post.
I have recently picked up a 67 coupe and I need to press and hold the brake pedal whilst turning the key to start the car. If this is not followed the ignition seems dead when the key is turned as if no power to the switch.  I have progressively changed the starter solenoid, brake switch on the steering Column and lastly the ignition switch but I have not succeeded in resolving this issue. Any thoughts or suggestions would be appreciated.
Thanks
Title: Re: 67 Coupe 289 Auto starting issue
Post by: GEOFF289 on November 14, 2020, 01:03:08 PM
Your '67 must have an option not generally seen on cars until several decades later. Modern cars, some at least, with a starter button and you just leave the "key"in your pocket require the brake to be held on for it to start.

I take it the car is an auto? Fox bodied manual Mustangs had a switch on the clutch pedal that prevented starting unless the clutch pedal was depressed. Autos just had a normal nss.

Unless someone has wired in some modern trickery to the starting circuit, I wonder if the brake pedal is interfering with some part of the wiring such that the starting circuit is only complete with the pedal depressed, something got pinched or something? Anyway, that's a weird one, even on these old cars that often throw up electrical issues.

Hope you get it sorted.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Megzee67 on November 14, 2020, 03:13:35 PM
Hi Gabs64,
As an ex sparky, I find the best way to approach a fault finding exercise is to progressively tick the boxes....so to speak.
1. When you turn the key [ before ignition ] do your instruments energize? [ Or do you need to press the brake pedal to have power to the instruments]
2. Are your brake lights working?
3. As the brake light switch is a " normally open " contact it should be simple to disconnect and bridge the two wires. This then may allow you to start without depressing the brake pedal......and should lead you more clues.
4. To meet Aus. compliance, the indicator/brake/reverse light circuitry needs to be modified so it could be that someone may have taken an under dash short cut. US cars have indicating tail lights. AUS cars have the reverse lights as indicators.
Try point no.3 as a simple initial test.
Curly one, but there may be a simple solution as opposed to a complex one.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: scollist on November 15, 2020, 08:32:32 PM
Sounds like a great anti-theft tool to me.

If it isn't a fault that is dangerous and likely to cause a fire (after investigation), maybe leave it as it is?
Title: Re: 67 Coupe 289 Auto starting issue
Post by: pgold on November 15, 2020, 08:58:08 PM
Was the car a auto originally? VIN number or TAG on drivers door ( left door ) will tell us?
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 16, 2020, 09:15:07 AM
Hi All thanks for your replies. I realise really tricky to diagnose over messages. I donít know the history of the car as it has been freshly imported and technically I am first owner here.Dash lights up, fuel gauge moves and indicators work but brake lights donít come on.Turning the key to start I get nothing. Hold the brake turn key starts. I can also start the car by turning the key and then bridging the solenoid and it ticks over without holding the brake. Interestingly if i unplug the dash bezel brake lights work when pedal pressed but still wont start normally. Very late last night I did find that one of the wires (Green) from the brake switch has been taped with the white and black stripe i that goes to the 5 pin solenoid near the fuse block. When I press the brake pedal I hear the relay click in so its supplying 12V to the circuit. I think that is where the issue is in the wiring that is not normal, itís definitely not factory. Not sure where that white wire originates from as it looks like it has been cut but i am guessing it should be either constant 12V or Switched 12V. Plans is to run a hot wire seperate from the switch to the relay and test that theory. P.S. what is that relay for?
Title: Re: 67 Coupe 289 Auto starting issue
Post by: scollist on November 16, 2020, 10:45:33 AM
I'm no expert, but it sounds deliberate to me.   There were no relays in 67 Mustangs as far as I know.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 16, 2020, 11:42:32 AM
I have nothing to compare but the the relay is 100% plugged into the factory loom that has to black wires from the loom. I couldn't quite work out the stripe on one of them.. The splice is deliberate though agree. Two additional wires have been added to that relay plug though. One going to ground and the other to the brake light switch wire that has bee spliced in. I am going to disconnect them tonight and see what happens.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: GEOFF289 on November 16, 2020, 12:29:35 PM
I guess it would be good to figure it out but as Shane suggests in his two posts above, it's starting to look like its a deliberate mod, and might be worth considering keeping it as an anti theft measure.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: scollist on November 16, 2020, 01:52:05 PM
From this 1965 diagram the relay would be on the Red-Blue (32) wire from the Ignition Switch to the Starter Relay (though most people call this the Starter Solenoid) - possibly even in place of the Starter Neutral Switch, which is exactly what the relay is emulating. 


The relay is standard-open, and is only energised when the Brake pedal is engaged - energising the brake light switch and therefore the relay become closed - enabling the connection from Ignition Switch to Starter Solenoid (presumably your two 'black wires' that are really dark blue with red stripe?).


I tried to find an equivalent diagram for 1967 Mustang, but the links I found want a free account created, so I didn't bother.


Maybe someone else has the diagram for 67 they can share? Or confirm it is still the same Red-Blue wire.


Electricals - only special people get the buzz!
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 16, 2020, 03:57:03 PM
Hi Scollist, thanks for the diagram. Its is a relay under the dash tucked up near the fuse box. I had a quick look again just before and I need a second pair of eyes and hands and I actually think its the factory air relay as one of the loom wires runs out through the firewall and leads to the compressor unit but don't hold me to that yet. I would leave it and still might but I still don't have brake lights so need to keep searching to at least fix that and if I fix both issues that would be a bonus. I disconnected the brake switch and jumped the wires but still no lights which I guess means the problem is further up. I am leaning to replacing the turn switch assembly of which I have ordered one.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Dwayne on November 16, 2020, 04:59:57 PM
I'd delete this thread and enjoy having a simple security measure  :leaving:
Title: Re: 67 Coupe 289 Auto starting issue
Post by: GEOFF289 on November 16, 2020, 05:52:32 PM
If the '67 brake light switch is the same sort of set up as a '66, they can be a pain. After having brake light problems I replaced mine with a micro switch from Jaycar. Much more reliable.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: 67FBGT on November 16, 2020, 07:56:46 PM
FWIW, IIRC when sorting my cars out there were several different brake light switches used on '67s, different spring rates (ie. sensitivity) and two installation configurations, from which to choose.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: pgold on November 16, 2020, 08:22:22 PM
are your turn indicators flashing red stop lights or a flashing amber reversing light?
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 16, 2020, 09:34:18 PM
Red stop lights.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 17, 2020, 08:36:44 PM
Just an update. Stumbled onto if the hazards are on it tryís to start when you turn the key every time the hazards flash. I guess its completing the power circuit just as by pressing the brake pedal. I have a turn signal switch on order and I will give that a try next. I give up after that providing everything else works and deal with it when I strip it down for a respray and engine refresh
.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: scollist on November 17, 2020, 08:47:46 PM
Itís not likely to be the brake light switch as you prove it works when you hear the relay click. So I think turn switch is a better bet (though I have no idea why  :ouch:)
Title: Re: 67 Coupe 289 Auto starting issue
Post by: scedd1 on November 18, 2020, 07:20:26 AM
if you want to know the ins and outs of your wiring loom, send an email to Midlife on the Stangfix forum. He has many customers in OZ and will give you good advice
Title: Re: 67 Coupe 289 Auto starting issue
Post by: pgold on November 18, 2020, 09:13:51 PM
are your rear left and right indicators working with current indicator switch.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 18, 2020, 10:15:35 PM
Hi Paul yes, indicators are working fine. Itís a real strange one. There is either a short or an open circuit somewhere in the starting power system and by pressing and holding the brake pedal the 12v going through the switch completes that circuit allowing the car to start via the key. As i noted earlier as well, putting the hazards on completes the power circuit as well every time the light flashes and turning the key to run it will turn the engine over every time the lights flash on. Interestedly turning the headlights on doesnít make a difference.  I donít hold much faith in the turn switch fixing it but I have read that they do cause some strange issues and there is a fair amount of voltage traffic through that switch to different areas of the car. Should have a new switch by the weekend so see how we go.
                                                                                                                           
Title: Re: 67 Coupe 289 Auto starting issue
Post by: unilec5544 on November 18, 2020, 11:25:08 PM
You seem determined to fix this problem by yourself and thats a good thing. If you have a multimeter you need to do a bit of wiring tracing. Fortunately early Ford cars where well colour coded. If you look at this diagram, you will see that you need to do some tracing. If you do not have a meter you can just make up a test light via a 12v feed or a small battery. There are only two wires going to the brake light switch. One from the light switch green/red and one to the brake lights, solid green. First trace these two wires and see where they go.

I do not seem to be able to post a diagram










Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 19, 2020, 03:58:36 PM
Nailed it!!! solved.

In my earlier posted I mentioned that there was a relay under the dash near the fuse box and it looked like a factory loom. I took a deeper dive under the dash and found that relay had been deliberately added. From my limited knowledge it appears the wire running from the loom under the dash to the ignition coil had been cut and the relay put in between. This is where the wire to the break switch comes in as there was a wire spliced into the 12v switched side of the switch to the relay so when the brake pedal was pressed it supplied 12v to the relay energising it and sending the voltage to the coil. I removed the relay and wire bridged those two terminals and wouldn't you know it starts as any normal car now. i will need to do a permanent fix but I will just wait and see if I have created any other issues that that set up was masking.

Thank you all for your support and suggestions as they all really helped.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: mwizz on November 20, 2020, 08:40:29 PM
Good job
Title: Re: 67 Coupe 289 Auto starting issue
Post by: evan on November 21, 2020, 09:26:02 AM
Nailed it!!! solved.

In my earlier posted I mentioned that there was a relay under the dash near the fuse box and it looked like a factory loom. I took a deeper dive under the dash and found that relay had been deliberately added. From my limited knowledge it appears the wire running from the loom under the dash to the ignition coil had been cut and the relay put in between. This is where the wire to the break switch comes in as there was a wire spliced into the 12v switched side of the switch to the relay so when the brake pedal was pressed it supplied 12v to the relay energising it and sending the voltage to the coil. I removed the relay and wire bridged those two terminals and wouldn't you know it starts as any normal car now. i will need to do a permanent fix but I will just wait and see if I have created any other issues that that set up was masking.

Thank you all for your support and suggestions as they all really helped.
Is the car auto? If so, does it start in gear? If the answer is yes, the Neutral safety Switch has been bypassed & the brake pedal switch/relay is doing its job.

Evan.
Title: Re: 67 Coupe 289 Auto starting issue
Post by: scollist on November 21, 2020, 09:43:30 AM
Nailed it!!! solved.

In my earlier posted I mentioned that there was a relay under the dash near the fuse box and it looked like a factory loom. I took a deeper dive under the dash and found that relay had been deliberately added. From my limited knowledge it appears the wire running from the loom under the dash to the ignition coil had been cut and the relay put in between. This is where the wire to the break switch comes in as there was a wire spliced into the 12v switched side of the switch to the relay so when the brake pedal was pressed it supplied 12v to the relay energising it and sending the voltage to the coil. I removed the relay and wire bridged those two terminals and wouldn't you know it starts as any normal car now. i will need to do a permanent fix but I will just wait and see if I have created any other issues that that set up was masking.

Thank you all for your support and suggestions as they all really helped.

So we determined it is was a deliberate addition, and removing it makes starting the car work as per factory (your original stated problem).

But later on you mentioned that you didn't have brake lights. In removing the relay has this problem been fixed?
Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 21, 2020, 09:51:40 AM
Hi Evan,

No wont start in gear neutral switch doing its job. I can only think that maybe it was set up that way to make it child proof or something like that. I might actually tuck up switch away somewhere and turn it into a kill switch set up.

Title: Re: 67 Coupe 289 Auto starting issue
Post by: Gabs64 on November 21, 2020, 10:10:37 AM
They are back as should be but i feel that may have been a seperate issue as I got them back by playing around with the turn switch connector plug and just unscrewed and reseated the switch itself in the steering wheel around the same time i sorted out the other prob. I cant give a definite answer on that one. I have a turn switch coming (due Monday) and I will replace it anyway since I have the steering wheel off and the seats out so access is better just to be sure.