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Discussion Starter · #1 ·
Backstory-- Last season I was having a problem with the car just randomly shutting off, as in full gauge sweep shut off. It would usually come right back. Found that the power wire that goes in to the fuze box in the engine bay had come loose from the T block that I have that connects to the battery in the trunk. Fixed that and it was all good, for a while. Slowly it started to miss like that again. Wire was fine though where it messed up before. Most of the time it only did it under dramatic turns. Couldnt track it down due to really only driving the car on course like that.

Cut to this weekend. First run was fine, no worries. Second run it only did it once, going into a hard decreasing radius turn into finish. Third run it did it a lot more, mainly in the hard transitions from one side to the other.

Pulled the car out of grid and checked some things. The wire connections for the inline fuse were a tad loose, but still tight. I got a half turn on them and it was all good. Just for giggles i pulled the wire that was the problem previously and cleaned up the ends and put it back. Got back in grid and took a run. It did idling up to the line and then it was much worse on course. So much so that I cut the course short and followed in the car before me. On the long return road it did it under idle speed and it flat out died so i had to bump start it.

Ive been leaving the xcal turner plugged in due to a P0172 that i cant figure out either :banghead: but several times on course i could hear the xcal rebooting itself like it had just plugged in, so power is being completely cut to the system.

Most times when it cuts power the car starts to buck like a bronco. I push the clutch in and it goes away.

At first I thought it was fuel related. Ive checked/replaced the sock on the fuel pump, and fuel filter, and im running a full tank of gas.

I plan on checking the other end of the red wire from the T, normally its run to the battery, and see if its messed up in the fuze panel. Im open to ideas though. Ill watch the videos from this weekend and see if i have a good example. I did get a video from inside of the gauges, but i havent had a chance to look at it.

Since its cutting main power our thoughts are:
- the red wire going into the fuze panel
-ignition switch wiring
-clutch pedal wiring (mainly because it stops when the clutch is pushed in)

Its super frustrating because the car is basically not drivable at the moment.
 

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1999 3.0 SilFro
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When I first got mine back together and was driving it on the highway for the shakedown, it would do that when I hit a large bump. PATS light on, gauge sweep, the works. In my case, there was a loose connection at the battery on the positive cable.

I'm still using the OEM battery terminals, so the positive cable terminal has the requisite large wire, and a secondary smaller wire bolted off to the side of the big one. It turned out the smaller wire was not tight. Once I snugged that back down, it never did it again after 7 events, so like almost 50 runs. I apparently just missed that one in the re-assembly process.
 

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Discussion Starter · #3 ·
Connections on the battery are tight and clean. Ground wire is connected to a rear seatbelt nut. Power runs up the drivers side , under the carpet, under the door trim, through the firewall.

It is a fairly old battery, i wonder if there might be something internal to the battery thats off.

I havent really had a chance to track anything down, but ill explore any ideas. This is priority at the moment in all my craziness
 

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Try cleaning and reseating the three big harness connectors by the timing cover and the bolt-together connector by the brake booster.
 

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Do you still have an original battery cable between the T-block and the starter? If so, it would be worth taking a close inspection for corrosion under the insulation.
 

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Jason Speros was diagnosing my random dead battery issue. After lots of probing of wires (and swapping the alternator) it turns out the white harness behind the speedo vibrates enough to not make contact despite being locked in place. The green/black wire completes the loop for the charging system in the cluster.

It was something that worked fine and you'd attribute to a bad cluster. But when we swapped them out he noticed it was sweeping the gauges as we put it back in. There's no loose pins, and spreading the contacts on the cluster connector didn't keep it snug so he jammed the head of a couple small zip ties in to put pressure on it. It works better, but prolonged vibrations will cause it to loosen again. You have to test it by getting the cluster out and moving the white harness around while the car is on accessory and see if it causes the meter to change or the gauges sweep.

The only fixes are to either replace that entire harness, or disassemble the body side connector and try to repin it. Or figure out something to wedge into the cluster side while it's hooked up to keep tension on it.
 

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Discussion Starter · #8 ·
Do you still have an original battery cable between the T-block and the starter? If so, it would be worth taking a close inspection for corrosion under the insulation.
yes it is. that wire is such a pain get to, but ive got extras. wouldnt be a big deal to put a new one on anyway to eliminate it
 

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I think the supercharger is the problem. Send it to me.

Can you datalog and see what is actually happening?
 

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1999 3.0 SilFro
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You know, I have a spare 2-bolt subframe…
 

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is a pop sensation
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I know this is a bit old, but years ago I had issues with the car stalling under moderate to hard braking (guage sweep, would immediately restart). I never truely figured it out, but it went away after replacing the 5+ year old battery. Only thing I can figure is the battery had something loose internally that would short under load. Could be something similar since your battery is 10 yo now.
 
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