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Not enough juice :\

Posted: Thu Feb 05, 2004 9:22 am
by Ferwoaza
Okay, I'm having an electrical issue with the FJ40.

If everything is wired up normally, the car won't start. Starter motor turns fine, and there is voltage getting to the coil (test lamp tested) but not enough current is getting through to the coil and onto the spark plugs to make them fire (pulled a plug and tested).

If I take the +ve wire going to the coil, and run it direct from the car battery, turn the starter over, the engine starts and runs fine.

I've cleaned up all terminals I can find and replaced all fuses I can find but when connected up normally, there just doesn't seem to be enough amps getting through to the coil in order to get the thing running.

Should I start replacing wires? Just thought I might post this here incase someone has a good idea for me to try :)

Posted: Thu Feb 05, 2004 10:43 am
by murcod
Murray, is the right type of coil installed? Some are designed to run with a ballast resistor in series (ie at a lower voltage)?

I think there is also circuitry to bypass the ballast resisitor at start up if one is used? (might be wrong there- someone else will know)

Posted: Thu Feb 05, 2004 11:40 am
by Ferwoaza
I figure the coil and everything with it is fine as it works when hooked direct to the battery...

Something is stuffing up when it goes through the normal car circuitry..

Posted: Thu Feb 05, 2004 12:57 pm
by carts
Murray,

Does the positive to the coil run straight from the ignition barrel, or does it run through a fuse? Either way, have you checked the ignition barrel or any terminals inside the car for corrosion? Any amount of corrosion will cause a voltage drop in the loom, therefore limiting current that the coil can pull. If connecting it straight to the battery fixes this issue, then I would suggest the fault lies in the loom back to the ignition barrel or even in the barrel itself.

If you have a multimeter, test the resistance across the terminals on the barrel.

Posted: Thu Feb 05, 2004 2:19 pm
by Ferwoaza
This is what I'm trying to track down, there is a red wire that connects to the +ve on the coil.

The other end of this wire, joins a black/yellow wire that is part of the loom and by the looks of it, goes through the firewall on the drivers side.

I'm trying to trace it to see where it goes exactly, should go to ignition barrell, but having trouble as the wires are a bit dirty and I can't tell the colours :oops:

Will look for a fuse, and will attempt replacing the wire from the ignition barrell to the red cable.

Posted: Thu Feb 05, 2004 3:14 pm
by carts
Before you destroy the loom, from the back of the ignition barrel, (if you can get to it easily) put a jumper wire between positive and ignition (thus bridging out the internal switching mechanism) and see if the car will start. Obviously if it does. then the problem exists in the barrel!!

Posted: Thu Feb 05, 2004 6:29 pm
by murcod
Murray it appears the FJ40's do have ballast resistors in the ignition wiring somewhere. Read the following link for an explanation of how it works and then you'll see why I mentioned it may be a problem (it's a Triumph site but the theory of operation is still the same):

http://www.vtr.org/maintain/ballast.html

Here's some info on converting a FJ40 over to HEI. I take it the same engine is in yours?

http://www.geocities.com/calcide/fj402fhei.html

Posted: Thu Feb 05, 2004 6:41 pm
by murcod
Just found this - sounds familiar!

http://www.funinbc.com/forum/topic.asp?TOPIC_ID=1885