ef to gq alternator problems

[olozmav]

OK. just done the ef 110 amp to tb42 alternator swap. Easy enough swap, modified bottom bracket, swapped pulleys, smaller bolt and nut in tensioner, bigger lug on charge wire others plugged straight in.
Problem is alt doesnt start to charge until motor gets a rev up to approx. 2300rpm. Once going though it seems to work fine still charging even at idle. Turn off and restart motor and nothing happens till it gets another rev. The alternator is a second hand mitsubishi 110amp out of an EF dont know whether to pull it out and put in some brushes or if its just normal for these alts to need a rev to get them going.
Any ideas would be much appreciated . Thanks.

[chimpboy]

I think this alternator has an exciter circuit that you need to wire in correctly, otherwise it takes a bit of time for it to start charging.

This is the "L" terminal (I think) which is meant to be wired to +12V (ignition power) via a lamp of up to 2 watts. The load from the lamp actually gets the alternator excited (electrically speaking).

Double check this before you follow the advice. However that is the area I think you need to look in.

Here's the diagram for a bosch:



It should be a similar deal for you mitsu one but I don't have a diagram for it.

Did you hook in the lamp correctly, I think it is IGN or CHG or some such in the instrument cluster and would have been wired in on the old alternator anyway. Does it light up when you first turn the key, before you start the engine?

[olozmav]

Thanks for the reply chimpboy. I think you might be on to something. When I turn the key before starting the battery light doesnt come on. I plugged the double pin plug straight into the new alt but had to stretch the wires a bit to reach. Im thinking I might have broken the warning light wire or the plugs are opposite in the new alt. Ill check it out in the daylight but i think you may have sent me in the right direction. Thanks again.

[chimpboy]

Any luck?

[mudmav]

ive got the same alternator in my gq and it does the same thing! have to rev it to about 2200rpm to get it charging but its only an initial rev and then it keeps on charging even at idle, i will watch this thread with interest so let me know who you go. thanks mate

[chimpboy]

From a little digging I think the Mitsu alternator should have the same basic S and L design, most likely. And the warning lamp should work in the same way - a small lamp in between a +12V ignition power source and the L terminal on the alternator.

[cooki_monsta]

i have the same alternator and it has the same problem, altho my car runs like a bag of shit when you first start it so getting it to idle properly generally kick starts the alternator

[mkpatrol]

From a little digging I think the Mitsu alternator should have the same basic S and L design, most likely. And the warning lamp should work in the same way - a small lamp in between a +12V ignition power source and the L terminal on the alternator.

Chimp boy is right on the money here, the alternator needs a slight load on the exciter (L circuit) wire circuit to get it to charge.

Any of you guys that is having the problem actually have the dash light hooked up?

If not how do you know its charging?

Anyway if you hook the light up & it still doesnt fix it Hella used to do a red lamp especially for the job, you could hook one of those up instead.

[olozmav]

Good to here its a normal thing. I did a few more checks; First pulled plug off back of alt and hot wired small wire to pos. on batt. to make sure dash light works and wiring is good = light came on all good. Next some volt tests probed plug while on alt. , ign. off 0 volts, ign. on (eng, not running)12.5v, eng. running before the rev 12.0v, and after a rev (idling) 14v.
So now thinking gq is either wired different re. the exciter light or maybe the EF just has a higher wattage globe to get the alt going. Anyway way now that I know its not the alt itself Ill probably settle for just giving it a rev.

[cooki_monsta]

From a little digging I think the Mitsu alternator should have the same basic S and L design, most likely. And the warning lamp should work in the same way - a small lamp in between a +12V ignition power source and the L terminal on the alternator.

Chimp boy is right on the money here, the alternator needs a slight load on the exciter (L circuit) wire circuit to get it to charge.

Any of you guys that is having the problem actually have the dash light hooked up?

If not how do you know its charging?

Anyway if you hook the light up & it still doesnt fix it Hella used to do a red lamp especially for the job, you could hook one of those up instead.

generally you can tell if your alternator is charging by looking at your volt guage on your dash, dont need a lamp to tell me that

[chimpboy]

generally you can tell if your alternator is charging by looking at your volt guage on your dash, dont need a lamp to tell me that

Of course but it's nice to have things working the way they were designed to.

[mkpatrol]

generally you can tell if your alternator is charging by looking at your volt guage on your dash, dont need a lamp to tell me that

Of course but it's nice to have things working the way they were designed to.

Yes Chimp, this is what I was getting at & its not such a silly question Cooki as my GQ doesnt have a volt meter











PS: I am a mechanic by trade so I do know a thing or two about cars.