alternator probs!!

[Lambomr2]

bit off topic with you mk1.5 owners but your better than the other forums so...
i have just done a supercharger conversion and am having some probs with the alternator. 1988 s/c engine into 1988 mr2

The car started first time and ran lovely ;) but after stating the car a couple of times battery started dying. i left the car running and after about 10mins the stereo turned off. Tested the battery and it was only running 11.5v.
Tested the battery after recharge and all was ok! started the car and checked the voltage whilst running and was still 12.1v. for the battery to charge voltage should be ~14v.
i have moved the battery to the front and was wondering if the earthing could effect the alternator?
I have a v.thick cable running to the back for the b+ and have earthed the old b- teminal to the strut top.(paint scratched away) at both ends.

The second thing is that i dont get a ignition light before startup? what would cause this.

And finally the Starter Cranks very slowly? this isn't due to the b+ wire as there is very low resistance though it.

What could it be? (i havent tryed cleaning the yellow plug yet)


p.s
If the alternator is faulty i have the alternator from the old 4age engine but the connections are slightly different.

The agze alt has a wire with a yellow plug and the battery wire coming out.
The age alt has a black socket and the battery wire. are these compatable if i change over the plugs?

Thanks guys

Mark

[BSM]

I would be looking at the fact you have no ign light first. You may have an issue with the wiring in the car not being the same for S/C as N/A and the Alt not getting a feed from the ign to energise and thus start charging. If the starter is slow I would also add an earth or 4 and see if that improves it. check and re check your connections for cleanliness and if in doubt use a meter to check resistance NOT continuity you shoulod get 0.2 ohms on thinner loom type wires and a little more on the thivker ones but def not a lot of resistance as that shows either a break or fault witht he wiring. Also check resistance to earth as well as to live to make sure you haven't got relays int he wrong way round.

HTH

BSM

[Paul Woods]

The SC has an external voltage regulator,not an internal one like the NA has,so the wiring circuits are completely different.

What you need to do is check 3 wires on the regulator,this is a small black box in the boot on the right hand side.

The plug on the regulator has more than 3 wires,but check these colours out with your meter,B/Y should have 12v showing with ignition switched on,so should the Yellow wire,lastly the white wire should show 12v permenant live with no ignition on.

If all 3 of those check out then you need to check continuity between the regulator plug and alternator plug.

The white,green,white/black and black wires from the regulator should all show zero resistance to the alt.

Do these simple checks first and get back,if this all checks out then its either the regulator that has failed or the alternator.

[Lambomr2]

Thanks guys

Will have a looky tonight.

I take it it would be the lil box next to the cooling fan box in the boot.

Will test the wires. hopefully not the alternator or reg though. if so have you got spares paul.


Cheers Mark

[Marksman]

If you run the NA alternator on the SC loom then you'll need to unplug the reg in the boot and bridge out two pins on it's connector. (You will lose the check engine light by doing this though.) Not sure if you can bridge out anything else to restore it though?

Owen.

[Paul Woods]

ive learned something here! you lose the CEL? really? bugger me.... i wonder why? cant see any sharing circuits between the CEL and alt? most curious!

[Lambomr2]

Second problem the supercargerv relay isn't working.
haved tryed an new relay but still dosent seem to click on!

any ideas.

will test the continuety between the wires and ecu!

thanks/

[Lambomr2]

sorry me being an idiot. s/c i working fine now.
Tested all the wires for the volt regulator and is all correct so it must be the alternator. doesn't explain the battery(ignition) light not working. will have to check the bulb.

:idea: as 'marksman' said If i was to bridge the three wires form the volt reg plug in the right order... would i be able to use the old 4age alternator?
and would it fit as the mounts are slightly different?

Cheers Guys

[Marksman]

Physical fit is OK, and you can use the same belt :thumbsup:

I think my memory may be off too on the check engine light. It may be that the CEL light works but the others don't with just one pair of wires bridged, that might make more sense :blush:

Owen.

[Mr2some]

Anymore news on this LamboMr2 ?
My car has a very similar prob and if you have got to the bottom of this it may solve my problem or give me pointers.
On my car i have the 3 lives at the standard oval plug (3sgte rev1 alt) but no dash lights only CEL . If i earth the yellow wire (i think) i can get the batt and oil light on :icon_conf :