TCCoA Forums banner

1 - 20 of 21 Posts

·
Registered
Joined
·
2,923 Posts
Discussion Starter #1
All:
I could use some here. This weekend, I just picked up the tbird from my rollcage builder and darned if it's not lookin' like a proper trackcar. I went to work re-installing some stuff my rollcage builder had removed (factory seat belts -- to remain street legal for now, the one speaker that'll fit, my ducting to use the heater as a secondary radiator, the rubber door molding, etc).

I also hit the weld joints with primer and fabricated a nifty Kill switch mounting panel. Please note that the kill switch is NOT installed right now (just mounted).


BACKGROUND
Now, the problem occurred when I started wiring up the electrical connections for my instrument gauges (oil pressure, ATF temp, and coolant temp).

* Seeing as how I needed 12V for the gauges, I started checking all the random connectors I had removed (near the dash) using my multimeter. Basically, I'd touch one contact of the meter to the pin being tested and the other lead to chassis ground. I decided to use the 12V constant from the connector that USED to go to cigarette lighter. To make sure that the gauges wouldn't run down my gauges, I wired a switch in series with this power line so I could cut off power to the gauges (I have a central instrument panel I fabricated with lots of switches on it).

* Mistake #1: At some point, I left the headlights on and ran down the battery. This necessitated a trip to the autoshop to charge up the battery. Allegedly, it's good.

Problem
When I came back and hooked up the battery again, I turned the car ignition to the "ON position". All the factory electrical stuff (trunk release, fuel filler door release, fan, etc) worked just fine. The problem is that once I tried to "start the car", everything went to hell. The shut down and it was like I had the battery completely disconnected.

If you shut the car off (move the ignition to the OFF position) and try again, the car remains dead.

Things I tried
* I checked all the underdash fuses w/ my multimeter's connectivity test. None were blown.

* I checked all the underhood fuses (including the 175A on one on the side of the power distribution block). None were blown.

* The multimeter still says the battery has 12V in it. It's not dead.

* I hooked up my other car via jumper cables and tried starting the tbird again. The behavior was exactly like the "original" (worked fine in the ignition on but everything dies when you try and start the car).

* I disconnected ALL of my additional wiring (power to the gauges, ground to the gauges, etc) and the problem still remains.

* Finally, I tried with my Honda's battery. The poles were reversed but I simply turned the battery around and managed to find enough slack to hook up the tbirds power/ground cables to the appropriate pole. Electrical devices are operational when you move Ignition to "ON" but everything dies again when you try to start the car. I reinstalled the Honda's battery back into the car and the Honda has no problem starting so whatever is causing problems in my tbird did not damage my Honda's battery.

* Yes, I verified the fuses again after each trial. None were blown.

Q: Is there something I'm missing? Perhaps an inline fuse I don't know about?

Q: Could I have fried something (maybe the ECU) in my testing of the various ports?

My gut feeling is that I have a short somewhere but I'm not sure where that could be.
- I know that even though the car is completely "dead" (no response from any electrical attachment), at some point (reset condition unknown), I can get the car to respond again.
- There is something in the car (perhaps a short) that is preventing the car from starting.
- I have no idea what I did to "reset" the system so that the car works when the ignition is ON.
- At the current point in time, I have the Tbird battery reinstalled back in the tbird with all the electrical items I installed (12V line for gauges, ground line for gauges, etc) removed.

Any suggestions would be graciously accepted. I'm supposed to take the car on the track on June 10th so I need this car back up and running again ASAP. :)

Thanks again for your help.
Regards,
-g
 

·
Registered
Joined
·
3,902 Posts
Well, this may be way off base, but anytime you turn the ignition key to start, you may notice that things in the car turn off for just a second while in the start position. Does the engine spin over with the starter? What does it mean when "everything went to hell?" I would focus on one serious problem. Once you find the culprit, it may be related to the other electrical problems.
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #3
Well, this may be way off base, but anytime you turn the ignition key to start, you may notice that things in the car turn off for just a second while in the start position. Does the engine spin over with the starter? What does it mean when "everything went to hell?" I would focus on one serious problem. Once you find the culprit, it may be related to the other electrical problems.
The starter doesn't even engage. Everything shuts down like you pulled the plug (or more realistically, some circuit breaker/fuse blew).
The funny thing is that I checked all the underhood and underdash fuses (in the boxes).

Are there fuses / some kind of time delay circuit breakers somewhere else in the car?
-g
 

·
Super Moderator
1994 Cougar XR7 DOHC/5-Speed
Joined
·
17,501 Posts
I assume you were able to start it after the cage was put in but before you wired in the gauges?

How many connectors did you test exactly? It sounds possible one got left unplugged or wasn't fully plugged back in. The one that immediately comes to my mind is transmission control harness connector since it's right by the dash to console connector the cig power comes from. If that's unplugged the starter circuit is open.

As Rob said, power is cut from many things under "start".
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #6
Hello

I would keep looking at the ing. Switch.

Where was a problem with them.
My car had a fire,(how I got the car)

So look there.

:wavey:
tbirdtess:
I think you are correct and this is my culprit. I took a look at the car with fresh eyes this evening after dinner and started going through the steps again.

1) I confirmed that the battery still had 12V in it and re-attached the leads.

1.5) I also confirmed that none of the fuses were burnt.

2) I noticed as I was walking around the car that the passenger side door lock had
a glow about it (I've sold my dome light and don't have any courtesy lights so your standard tests won't help me here.

3) To confirm if power was propagating through at least some of the car's electrical systems, I took a deep breath and pushed the electric trunk release and the fuel filler door release buttons. Both worked repeatedly.

4) As soon as you mess with the ignition switch though, the trunk/fuel filler release buttons cease to work. No gauges (the factory cluster) light up and nothing else happens.

5) I can "reset" things by disconnecting the battery and reconnecting it. The door light comes back on and the cycle may begin all over again (i.e.: all electrical stuff goes dead after you try moving the ignition switch around).

I cannot explain exactly what is going wrong here but it definitely looks like my ignition switch is going wonky. My buddy, the previous owner of this car, had a problem with the key ignition so he just pulled this ignition switch out of the steering column. It might have been on its last legs and my unluckiness just happened to coincide with me screwing around with all the electrical wiring (just to add fancy gauges).

Q: This is the part I should be targeting, right? I apologize for the over saturated picture. I was kinda excited about having my first legit lead to this problem.



Ford Part # F4DC-11572-AA

Oh, I can also get this part from autozone for $16.95 w/ a nice return policy (to confirm if it works). I know where I'm going tomorrow morning!

-g
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #8 (Edited)
Unlikely. The fuel door and trunk release circuits are part of the power seat circuit, thus go directly from the power distribution box to the 20A breaker and to the switches.
Just for some clarification:
1) I was able to drive the car back from the rollcage builder w/o any fuss. I did look like a bit of a doofus though w/ the white rally-style helmet in this gutted out car. Lots of strange looks driving from Sacramento to SF.
2) The only circuit I recalled unplugging was one of the two connectors going into the shifter. One was for the OD button (left it connected) and since the other one seemed to go right underneath where the shifter illumination would be, I figured it was for lighting. I went ahead and reconnected it. I'm seeing the same behavior as I reported in #6 (fuel door, trunk release, and door keyhole illumination work, you try and run the starter and all power in the car dies.
3) The only connectors i tested looking for power were ones I have disconnected already or didn't have something already plugged into them. Example: cruise control amp (removed from car), airbag diag modules (removed from car), OBDII, some of the small plugs that went into the glove box lighting, etc.


Hrm. Thanks for the suggestions, everyone.

Tonight, I plan to do the following:
* Ill check the manual and look for the transmission control harness tonight. Maybe I did unplug something inadvertently.
* Im going to try a new ignition switch. f the power is cut from a bunch of other electrical devices when you try and run the starter, that might explain why all the other electrical circuits (like the one you outlined for the fuel filler/trunk release latches) cut out... and stay cut out until you disconnect/reconnect the battery.

-g
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #9 (Edited)
Alright, I played with the car some more tonight.
Replacing the ignition switch didn't work.

Q: What is this box? It looks like some kind of relay but what system is it related to?

I noticed it hanging loose; I suspect it came out when my rollcage builder was cutting up the dash.

Finally, at the risk of further embarrassment, I decided to make a quick and (pretty awful) video. I'm hoping one of you folks might be able to better diagnose the issue for me. FWIW, the mike in my phone makes me sound like I'm 12.

Procedure in Video
1) Attached power leads to battery posts.
2) Noted that we have power to the car (illumination around keyhole, trunk release, fuel filler door release).
3) Switched ignition back to "Accessory" position. Stereo works.
4) Thought about leaving stereo on to show car dying but realized that this would mask any other (potentially useful sound).
5) Moved ignition switch to Ready position.
- Gauge cluster lights should be on but they aren't
- Note you don't hear anything from the fuel pump. IIRC, there should be a whirring sound as the fuel system gets pressurized.
- Fuel filler door/trunk release circuits still work.
6) Tried to start the car.
- Heard a "whirr.. chunk"
- Then the car goes dead.
- Nothing electrical works anymore even if you move the ignition switch back to the other positions.
7) The only way to reset things and start the cycle all over again is to disconnect and reconnect the battery.


I'm supposed to take this jalopy on the track next Friday to rest its reliability and handling before my 24 Hours of Lemons race.
Help!

Regards,
-g

PS. If anyone in SF wants to take a crack at it in person, PM me. I'll be glad to compensate you with any of my spare/takeoff tbird parts (from my sales thread) and/or beer.
 

·
Premium Member
Joined
·
1,150 Posts
Top pic is your flasher relay.

I would try jumping the solenoid too, good way to bypass a lot of things that could be affecting it. Check anything electrical you may have unmounted/disconnected that should be connected to make a ground (open circuits). Also get a trouble light and see if the welder inadvertently melted something behind the dash (if you haven't already). Pull the cluster out and see if anything looks melted or if the blue circuit stuff got torn somewhere. Also make sure the clips to the cluster are both all snapped in tight.

It's weird because it stays that way unless you disconnect the battery then it's able to reset itself. Like the computer is receiving a fatal error that shuts down the car to prevent you from harming it by trying to restart it. Do you have a scanner to check for codes?
 

·
Super Moderator
Joined
·
5,131 Posts
I'd walk through ALL the battery cable connections (hot and ground) and verify there's no corrosion or paint or anything in them.

That's exactly what a bad connection will do to you - when the current hits it for the start, it opens, and doesn't close again until you remove the power (the removal / reattachment of the battery causes it to move enough to break through the corrosion).

Possibly paint on the motor where the ground wire goes?

Maybe a bad battery clamp (if it's one of those replace-the-ends?)

If nothing else, I'd try a new ignition switch (or at least another one!)

RwP
 

·
Registered
Joined
·
2,073 Posts
I agree with Ralph check your battery connections and cables. And yes in the video you did sound like you were 12
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #13 (Edited)
1) I will recheck the battery connections. I remember that one of the clamps was worn (the one of metal clamp arms was cracked due to fatigue). I understand that resistance in a circuit can go up if a connection isn't solid so I'll deal with this issue tonight.

2) No painting was done in the engine bay.

3) I will also take a look at the starter solenoid as you folks have suggested.

-g

PS. A rollcage makes working underneath the dash a more acrobatic affair.
 

·
Super Moderator
1994 Cougar XR7 DOHC/5-Speed
Joined
·
17,501 Posts
I'd walk through ALL the battery cable connections (hot and ground) and verify there's no corrosion or paint or anything in them.

That's exactly what a bad connection will do to you - when the current hits it for the start, it opens, and doesn't close again until you remove the power (the removal / reattachment of the battery causes it to move enough to break through the corrosion).

Possibly paint on the motor where the ground wire goes?

Maybe a bad battery clamp (if it's one of those replace-the-ends?)

If nothing else, I'd try a new ignition switch (or at least another one!)

RwP
Agreed, otherwise I'm honestly stumped. I'd check around any of the mounting points of the cage to make sure any interior ground straps or buses weren't damaged as well.
 

·
Super Moderator
1997 Thunderbird 4.6, 1998 Mark VIII LSC
Joined
·
9,525 Posts
I definitely agree about the battery connection. On the Cougar it has one of those universal style battery clamps on the positive lead, which was a bit loose but I didn't realize it until one day I went out to the car to try to start it after work. Put the key in, turned it to ON, lights came on like usual but when I went to turn it over, everything died. There was no power, even if I shut the key off/removed it and tried again. I jiggled the connections and I knew it was the culprit when the underhood light came back on. A few tries later (died a few times like it did initially) and I managed to get it started so I could get it home to tighten the clamp back down.
 

·
Registered
Joined
·
3,902 Posts
I still say, pick one of the circuits that is giving you a problem and get a wiring diagram for it, from power distribution (battery, PDC) all the way to the components and ground buses. From there you find out what is not showing up where it is supposed to be. I could possibly help you with a diagram if you gave me the year and engine the car is wired for and which circuits you want to check. You will need a multimeter at least to get to the bottom of this on your own. Let me know about the diagrams. :D
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #18
I found my problem and you guys were correct, it was the battery clamp connection.
I knew something might be up when I took some sandpaper to the poles and the inside of the clamps and a serious amount of oxidation came off of them.

The car works again... and just in time for our shakedown track day next Fri.
Thanks for all the input, guys!
-g
 

·
Registered
Joined
·
2,923 Posts
Discussion Starter #20
Glad you got it going in time. Whens the race?
I have a shakedown track day next Fri.
I'm targeting the

Items left:
* Finish the suspension tweaking (to be done before the trackday)
* Sensors are installed; need to wire them to the gauges
* Kill switch + Panel installed; need to wire it into the car and possibly relocate the battery
* Passive aerodynamics
* Active aerodynamics
* Painting the theme

-g
 
1 - 20 of 21 Posts
Top