1JZ RUNS!! need charging issue and grounds location help

[NecroCyde]

Hey guys,

about 5 weeks ago i got my 1JZ running!!! after 4 years of messing around and no progress, figuring out i had been given the wrong ECU, having to pull the head as we found out it had 4 stuck intake valves and no compression on 4 out of 6 cylinders because of that. Got a rebuilt head from a forum member, 2JZGTE HG and ARP headstuds from DM and a few broken connectors fixed and It fired right up!

Got it moving under its own power a few days later and it pulls hard and is running quite strong, idles good, starts easy. Temp stay good and oil pressure seems good as well.

I am trying to sort out why i dont think i am getting any charge from my alternator. I have a new serpentine belt and everything is connected. Good battery, new ground cable to the battery terminal, all electrics are getting juice from the looks of it, but it doesnt appear i am getting anything from the ALT. The car sits at 12.54 volts off and 12.08-24 running, slowly discharging lower and lower overtime. From the voltmeter in the car it looks like at the higher RPM it is going up, so that must mean i am getting something.

I am wanting to rule some things out before I order a rebuilt alternator.


Where do the two grounds go exactly on the jza70 1JZ? There is the one on the intake side which is currently mounted to the intake manifold as i seem to remember thats where it originally was, i am probably wrong. There is also the one off the harness by the alternator itself that is mounted currently to the fender well as thats the mounting point that looked like it would reach. This could also be wrong, should it be mounted to the frame or perhaps the engine?? Also is there supposed to be a ground from the engine to firewall like on the 7m's, i am thinking not from my research. There is also what i believe is a hot lead on the ma70 body harness near the fusebox that i suspect was supposed to reach the 7m alt or perhaps the positive lead from the battery, but i am not sure. I am going to put in a fresh ALT relay in and clean up the connections to the alt and dust it out with compressed air.

I have searched and found nothing useful, So where are the grounds supposed to go on the 1JZ? TSRMs were not alot of help either.

Thanks again!!!

 

[87supraguy]

The car sits at 12.54 volts off and 12.08-24 running, slowly discharging lower and lower overtime. From the voltmeter in the car it looks like at the higher RPM it is going up, so that must mean i am getting something.


Where do the two grounds go exactly on the jza70 1JZ? There is the one on the intake side which is currently mounted to the intake manifold as i seem to remember thats where it originally was, i am probably wrong. There is also the one off the harness by the alternator itself that is mounted currently to the fender well as thats the mounting point that looked like it would reach. This could also be wrong, should it be mounted to the frame or perhaps the engine?? Also is there supposed to be a ground from the engine to firewall like on the 7m's, i am thinking not from my research. There is also what i believe is a hot lead on the ma70 body harness near the fusebox that i suspect was supposed to reach the 7m alt or perhaps the positive lead from the battery......

so a couple things. your voltage reading with the car on, this was taken with a multi meter? should be seeing about 13.5v +/-.

as far as ground wires go (off memory) there is one: head to firewall, trans to firewall/chasis, harness grounds to intake manifold, block to battery, battery to chasis. (the ground you speak of by the alternator) in my experience i have not seen a ground wire in that section of the bay... could be the positive terminal for the alternator.

this leads to my next question... what wires are currently hooked up to alternator? i know on some harnesses (not sure if all do), the alternator wires are built into the harness and exit by the fuse box and in many case with importers these wires are cut here. did you extend your original alternator wires to the new alternator location?

 

[NecroCyde]

Yes, the readings were with a multimeter. The ma70 engine harness to fuse box plug was swapped in and 3 other wires were connected with clips done by the guy who did my harness. There is that other ring connector by the fuse box that i believe possibly goes to the alternator on the 7M that is just hanging there, I am wondering if this is the issue. I remember i was told that the bigger cable by the alt was a ground.

I should take pictures of what i am referring too and that could by chance help things.

Perhaps if somebody could take pictures of their fusebox plug, alternator wiring and grounds for reference that would be awesome. This kind of information would be invaluable and could be stickied as well.

Edit***, the three wires with clips were originally soldered together, when a pulled the head and put things back together i soldered in clips for future disconnection, They are insulated and shrink tubed. I recorded the color codes so they have not been incorrectly connected.

 

[xzeror]

my 2jz swap does the same thing but only when cold. The volts are low and move with the rpms, the car tries to die and i have to give it some gas so it doesnt. After a few seconds the volts rise and then it stays put. After driving the car it wont do it again on start up unless its been a while since i turned it off.

Going to check my grounds and sand it to the bare metal (recently repainted and cleared the engine bay).

 

[87supraguy]

yeah pics may help. but the "ring" connector from the original 7m alternator needs to be extended (you can buy the long thick guaged starter wire from autozone) so power gets sent back to your battery... i'll take a pic of what i mean...

 

[87supraguy]

the guy that did you harness. did he use or tap into the original alternator wires?

 

[87supraguy]

my 2jz swap does the same thing but only when cold. The volts are low and move with the rpms, the car tries to die and i have to give it some gas so it doesnt. After a few seconds the volts rise and then it stays put. After driving the car it wont do it again on start up unless its been a while since i turned it off.

Going to check my grounds and sand it to the bare metal (recently repainted and cleared the engine bay).

have you tried another battery? sounds like an old battery, weak battery with low electrilites?

 

[NecroCyde]

I am using a fresh battery, If the original alternator ring lead off the fuse box needs to touch the 1jz alternator on the other side of the engine bay then my guess is that is the culprit and first place to start.

If the engine harness intake manifold side ground is for the intake manifold then we are good. The auto tranny ground is connected. The ring connector on the 1jz harness is connected to the fender wall which seems right, unless somebody else can chime in. I will double check it and clean it up too. So I will look for a alternator wire extension at a parts store and use that if thats all that is needed. The alternator must be giving power to the engine harness, but not the battery. The battery must be giving power to the starter and chassis but perhaps not the engine? So we just need to get power from the alternator to the positive terminal and we should be golden then. What do you think, anything else that could be wrong? Should i also ground somewhere on the head to the firewall as well?

 

[NecroCyde]

I dusted out my alternator thoroughly, can i use brake cleaner to clean it up more? I am going to pick up an extension to hook up the ma70 alt cable to the alternator. Confirmed with a brand new battery it is getting discharged, i have my intelligent charger on it right now at 6 amps.

On a side note, i got my powersteering leaks fixed and started hooking up my boost guage. Hosetechniques hose off the intake manifold, through the firewall to where it will sit where the ashtray would be.

Shit if i can get the charging issue solved this thing is roadworthy, few more things and ill start driving it to work!

 

[87supraguy]

If the original alternator ring lead off the fuse box needs to touch the 1jz alternator on the other side of the engine bay then my guess is that is the culprit and first place to start.

The ring connector on the 1jz harness is connected to the fender wall which seems right, unless somebody else can chime in....

i want to see a picture of the "ground wire" going to the passenger side fender... the "ring" cable that was originally on your 7m alter needs to be hooked up to the little post on the alternator... this cable goes to your fusebox and from the fuse box to the battery.... what do you currently have hooked up to you little post on the alternator now?

So I will look for a alternator wire extension at a parts store and use that if thats all that is needed. The alternator must be giving power to the engine harness, but not the battery. The battery must be giving power to the starter and chassis but perhaps not the engine? So we just need to get power from the alternator to the positive terminal and we should be golden then. What do you think, anything else that could be wrong? Should i also ground somewhere on the head to the firewall as well?

yeah go to the parts store and look around the battery section there should be prepackaged long thick gauged starter wire. i bought a 5ft starter wire (rather have more than enough) only issue is you'll need to find a way to mate it to your old alternator wire. there is really only 3 things that will cause a "good" battery to not get a charge. alternator wiring (common after a swap), bad alternator and alternator fuse in the fuse box.


post a pic of your your alternator... i need to see what you have hooked up on it and also take a pic by your fuse box where the original alternator wires and connections were. want to see if i see anything that is not being used.

 

[87supraguy]

here's a link i posted questions i had about this specifically. this may help clear up some things. also has some pics.

http://www.supraforums.com/forum/sh...ternator-wires&highlight=1jz+alternator+wires

 

[87supraguy]

so right now you have the alternator plug from the harness plugged in but at the other end of those wires, where are they spliced or connected to?

if your using a 7m fusebox with a jza70 harness you still have to extend the original 7m 3 pin round plug to your new jz alternator. the power wire (ring wire with raised edges) needs to also be extended to the ALt. the reason your getting a reading of power from that wire is because that wire goes to the fuse box, to the alternator fuse in the fusebox and then off to the battery. once you Hook it up this way. i guarantee you alternator will start charging your battery. i've done two jz swaps now and this has to pretty much be done on every swap... you just extend the original 7m alternator wires so they reach the JZ alt location.

 

[NecroCyde]

Alrighty guys, solved!!!

The fat flat 4 guage ring lead on the alternator side of the 1jz is part of the alternator hot lead that should go to the fuse box. In the case of a 1jz swap into an ma70, the previously mentioned alternator raised edge ring lead at the ma70 fusebox. The raised edge ring lead on the 1jz alternator is apart of that fat flat 4 guage lead that at first glance looks like a ground. ITS NOT! I am unsure as to why that whole stock 1jz alternator cable is so short and comes no where near the battery. The jza70 must have had a junction on the passenger side that goes around and links up with the jza70 fusebox.

So when doing a 1JZ swap you can either tie into that fat lead, extending it over to the ma70 fusebox alt cable or cut that shit out and run a fresh 4 guage high strand cable from the 1jz alternator to the ma70 fusebox alt cable.

I am going to post up the pics i took and i also want to update that technical thread here on SM somebody else started regarding 1jz alternator wiring. There isnt alot of information on it and there should be. Hams on SF covered the voltage regulator wires, but the actual charging wasn't covered.
Regardless my problem is solved, I am getting 14 Volts out of this alternator, charges like a beast, that will probably drop a bit as the battery is recharged as it was down a bit from the previous nights tests.

So that leaves only one chassis ground for the engine, i am going to run one to the passenger firewall like the 7m, heard of some people doing this as well.

 

[xzeror]

pics please^ i think i might have the same problem