Guest FullAttack Posted September 6, 2014 Share Posted September 6, 2014 Yo dudes, Iv got a supra that had 1 type of Ign barrel plug, bought a lock set off some dude, the plug is different... So.. I pulled the back off my one and put it on the new one.. It's looks the same on the inside, the plug shape and pin pattern on the back is different, it fits straight on... The car starts and runs... Now the issue.. I'm seeing 18volts at the battery... I don't know how this is even possible.. I don't know if this is an issue directly connected to the Ign barrel plug swap, or something like the alternator about to poo itself.. I never saw the car run until i fitted the new barrel so don't know if it was doing it before. It's a decent volt meter that iv checked on another car to make sure it's reading right. The question is, has anyone else done this with the Ign barrels, without the 18v issue? Kind regards Dale Quote Link to comment Share on other sites More sharing options...
straightsix Posted September 6, 2014 Share Posted September 6, 2014 I wouldn't have thought changing the ignition barrel would give you 18v as it's only a switch that completes a circuit. Personally, I'd probably start by cleaning all the earth points and make sure there's good ground on the alternator Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 6, 2014 Share Posted September 6, 2014 If you are seeing 18 volts and the wiring to the alternator is good, I would suspect the regulator inside the alternator has failed. They are available separately if you or anyone fancies dismantling the alternator and replacing it. they can also be tested away from the alternator with the right gear and knowledge. Quote Link to comment Share on other sites More sharing options...
Guest FullAttack Posted September 6, 2014 Share Posted September 6, 2014 Ok sweet, I could just unplug the Alt while it's running and see what the voltage does.. I do have a new reg pack with the circle plug, havnt looked to see if the supra is circle or oval. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 6, 2014 Share Posted September 6, 2014 If it stays at 18V with the alternator disconnected you have a most unusual "12 volt" battery in the car Quote Link to comment Share on other sites More sharing options...
jagman Posted September 6, 2014 Share Posted September 6, 2014 It's unusual to over volt from an alternator , the regulator inside the alternator is fed with a sense wire , usually marked "s" , check the wiring diagrams for its route - this is where the voltage is sensed , if this wire is high resistance or corroded or loose , the alternator always senses low voltage , so it pushes up it's output to max . Max output is usually circa 18v , limited by a surge diode inside the alternator . I don't have the diagrams to hand but check the sense line run and see if you have disturbed any part of this run doing the ignition switch Quote Link to comment Share on other sites More sharing options...
jagman Posted September 6, 2014 Share Posted September 6, 2014 A very quick check is to remove the 7.5 amp ALT S fuse , this is where the voltage is sensed from for the alternator - check the fuse blades are not corroded and the fuse sits in it slot nicely , maybe clean the terminals with emery paper . And wiggle a bit - see what happens to the voltage Quote Link to comment Share on other sites More sharing options...
Guest FullAttack Posted September 6, 2014 Share Posted September 6, 2014 Yeah I'll have a go on with the Alt.. I almost always wire the alt wires direct to the positive post of the alt on driftcars, so they constantly charge flat out.. They usually only make 14.5-15.0 volts. I have just noticed aswell that its making 15v at the battery when engine is off.. Wtf.. Quote Link to comment Share on other sites More sharing options...
MC_Bob Posted September 6, 2014 Share Posted September 6, 2014 Batteries float and take a while to show idle voltage. Its an alternator fault. It should regulate to max of 14-15v regardless of sensor wire. Quote Link to comment Share on other sites More sharing options...
Guest FullAttack Posted September 8, 2014 Share Posted September 8, 2014 This is irritating to say the least.. Started engine and connected the volt meter to the battery, it climbed slowly upto about 20volts.. Engine didn't run to smooth.. Unplugged the 3pin plug off the Alt.. It steadilly dropped down to 9.5 volts over about 2 mins.. Engine ran sweet between 15v & 10v.. Plugged the plug back in and it didn't charge.. Obviously wasn't seeing enough volts on the signal to tell it to charge.. Put jump pack on and it immediately started charging again and jumped voltage back upto 20v straight away.. So.. I had a look through my spare alternators, iv got 7 or 8, mainly 1j ones and mainly broken.. I only have one spare NA 2j alt so I chucked it on.. I don't know for sure that it works(I'm 80% sure it does), but it only takes 10mins to swap so thought I'd try it.. It did the exact same thing as the original Alt.. Same voltage while plugged in, same thing when unplugging it, etc.. I can't see that 2 alternators would do the exact same thing if they were both broken.. I think I have a problem with something else.. Either the insides of the ignition barrel switch(probilly not), or somewhere along the wiring for the alternator maybe.. I'm lucky in the fact I have another supra that runs sweet.. I'm going to swap alternators just to be sure.. Then see which type of ignition barrel my other one has, possibly swap them if it's the right one.. If this fails, I'll start investigating the alternator wiring.. It actually wouldn't take long to rewire it from end to end.. I think all 3 wires go back to the fuse board in engine bay so could rewire with 3 new wires in a new sleeve so to not disturb the original loom. Quote Link to comment Share on other sites More sharing options...
Guest FullAttack Posted September 15, 2014 Share Posted September 15, 2014 Tried another alternator.... BOOM! Fixed... Lol So yeah, Ignition Barrel plugs CAN be swapped.. Car is still running lumpy, probilly the fact it's on old fuel, probilly wants spark plugs, etc.. I'll crack on and do all this now the voltage is sorted:thumbs: Quote Link to comment Share on other sites More sharing options...
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