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Help!! - Bundy 4WD wont engage

Posted: Mon Mar 01, 2004 9:07 pm
by Skip
Some of you may know I just completed an engine conversion in my jap import bundy. When doing the conversion I unplugged the loom to the transfer case when pulling the motor out. After the conversion was finished I hooked it back up and it all worked fine. In the mean time ive had a few electrical gremlins which have just be solved, but my electric 4WD engage wont work now. If I push the button the switch does not light up like it used to, the light wont come up on the dash and I definitely dont have any 4WD. Checked the loom and that is still plugged in, pulled the dash off and the switch is plugged in, what else should i look at to find the problem? Are there any fuses?

Cheers

Posted: Mon Mar 01, 2004 9:08 pm
by Bluey
if this is electric activation, do you have wiring diagram (manual?)

Posted: Mon Mar 01, 2004 9:18 pm
by Skip
Yes to electric activation, no to wiring diagram, i dont even have an english manual, just a japanese one with lots of interesting cartoons :)

It's an LJ71G, so the wiring would probably be pretty similar to a LJ70 Bundy. Anyone got a diagram?

Posted: Tue Mar 02, 2004 11:10 am
by BUNDERA
Heya skip good to hear that your conversion went/is going well. Anyway I am pretty sure that you havnt connected up the vacume lines which are shown in the picture below (your 4x4 actuator) to the inlet manifold.

Hope it helps.

Good luck with it all.

Regards,
Nick

BTW you cant actuate 4x4 while boosting with our setups..

Mine is living 14PSI BOOST!

Posted: Tue Mar 02, 2004 3:09 pm
by Skip
Thanks BUNDERA, im pretty sure I had the 4WD working when it was originally finished, but maybe I didnt, I will check those vacuum lines.

BTW im running 15 psi, car made 200rwhp @ 4000 rpm before ignition started to break down. Putting a new set of igniters on, should get a tad over 300 rwhp :shock: :twisted: :armsup:

Posted: Tue Mar 02, 2004 6:22 pm
by +dj_hansen+
200 rwhp, thats huge! :twisted:
What engine are you running?

Posted: Tue Mar 02, 2004 7:45 pm
by Skip
Toyota 1JZGTE with Haltech computer, custom dump pipes, exhaust and big intercooler :)

Posted: Tue Mar 02, 2004 9:42 pm
by Bundytime
mmmm can u still get high range when u engage the stick????

Posted: Wed Mar 03, 2004 9:22 am
by Skip
BUNDERA: Thanks man your a legend!!!!! I didnt hook the other ends back up to the manifold, I just looped them round to each other. Anyway the 4wd is working again now, only problem is it wont engage/disengage at idle. I assume this is because the signal of the manifold is not as strong as that from the old vacuum pump. If i give it a few revs it works though.

Posted: Wed Mar 03, 2004 7:22 pm
by BUNDERA
Awesome man glad to hear you are back on the road again.

As for the disengage at idle I had the same problem but i seem to have fixed it. You need to connect the vacume hose to a place on the inlet manifold AFTER the throttle body and that should fix your problem.

I still find that it requires a little rev or three every now and then.


Regards,
Nick

Posted: Sat Mar 06, 2004 10:39 pm
by dumbdunce
BUNDERA wrote:
BTW you cant actuate 4x4 while boosting with our setups..



plumb it into the vacuum reservoir under the brake booster...

Posted: Sun Mar 07, 2004 12:32 pm
by Skip
dumbdunce wrote:
BUNDERA wrote:
BTW you cant actuate 4x4 while boosting with our setups..



plumb it into the vacuum reservoir under the brake booster...


Cant do that i turfed mine :)

Posted: Sun Mar 07, 2004 1:22 pm
by dumbdunce
Skip wrote:
dumbdunce wrote:
BUNDERA wrote:
BTW you cant actuate 4x4 while boosting with our setups..



plumb it into the vacuum reservoir under the brake booster...


Cant do that i turfed mine :)


good work :)

tee it into the brake booster vac line then. or I have a spare vac canister, free to pick up.

Posted: Tue Mar 09, 2004 9:20 am
by Skip
BUNDERA: Took the car for it's first proper drive since hooking the 4WD activation back up, and have a MAJOR problem. When I must get to a certain vacuum point usually after I shift into third, the 4WD tries to actuate without the button even being pressed, this causes alot of gear grinding noises and me slamming on the brakes, at which point it stops trying to engage again. I know one of the solenoids is for engaging and one is for disengaging, what the hell would be causing it to engage by itself?

It is all working fine at low RPM and speed, one thing I havent tried is engaging the 4WD, then driving the car and seeing if it tries to disengage by itself.

Posted: Tue Mar 09, 2004 3:04 pm
by bundyboy
sounds nasty!!!

Posted: Tue Mar 09, 2004 6:13 pm
by dumbdunce
Skip wrote:BUNDERA: Took the car for it's first proper drive since hooking the 4WD activation back up, and have a MAJOR problem. When I must get to a certain vacuum point usually after I shift into third, the 4WD tries to actuate without the button even being pressed, this causes alot of gear grinding noises and me slamming on the brakes, at which point it stops trying to engage again. I know one of the solenoids is for engaging and one is for disengaging, what the hell would be causing it to engage by itself?

It is all working fine at low RPM and speed, one thing I havent tried is engaging the 4WD, then driving the car and seeing if it tries to disengage by itself.


it is because you have positive pressure on the "wrong" side of the 4WD actuator diaphragm; you have to have it connected to a CONSTANT vacuum source; the cheapest easiest way to do this is to tee it into the brake booster line on the booster side of the check valve.

Posted: Tue Mar 09, 2004 7:37 pm
by Skip
dumbdunce: What booster line are you talking about, the one from the manifold? In that case I dont have a check valve in the line, the line goes straight from the manifold into the booster. AFAIK all brake boosters have a check valve in them internally.

Posted: Tue Mar 09, 2004 8:08 pm
by BUNDERA
ok mate I think I know what the problem is this time too!

Ok the crunching noise is because the freewheeling hubs arent loked in.....in your case I you probly dont want them locked in as u were on street i take it... correct me if i am wrong.

As for the cause of it having a mind of its own, going in and out of 4x4, would most likely be becuase you dont have a "one way valve" inline with the vacume hose going to the actuator(s). This oneway valve makes sure no air is forced into the actuator.

I will try and find a pic of one of these valves and post one up. I will also see if I have a spare one in my garage I could send for you to try.


Regards,
N i c k

Posted: Tue Mar 09, 2004 10:59 pm
by Skip
Yeah your dead right. Im pretty sure i can get a 4mm lump end one way valve from tyco, enzed, atkins etc.

It could be a pretty handy system if you think about it more. If it had the type of 4wd like the pajero which you can shift 4H up to 100 km/h, you could hook it up so when you came on boost 4wd instantly activated to stop wheelspin :) Or perhaps a torque sensing transfer does the same job but alot simplier :? :?: Is that what GTR's have?

Can you engage bundy 4WD when moving like a pajero as long as the hubs are locked? Is that what you were infering BUNDERA? I don't know cause my bloody owners manual is in Japanese.

Posted: Wed Mar 10, 2004 9:14 am
by dumbdunce
Skip wrote:dumbdunce: What booster line are you talking about, the one from the manifold? In that case I dont have a check valve in the line, the line goes straight from the manifold into the booster. AFAIK all brake boosters have a check valve in them internally.


some have internal check valve where the hose goes in, I just checked and the bundy is like this. you can get a inline brake booster check valve from a brake shop for a few bucks.

Posted: Mon Mar 15, 2004 1:54 pm
by Skip
Fixed it up with a non-return valve, working sweet now :)

Posted: Tue Mar 16, 2004 8:59 pm
by BUNDERA
Great stuff mate. Glad it worked.

Have a good one and if you have any other questions or probs dont hestate to ask.

Cheers,
Nick

Posted: Tue Mar 16, 2004 9:03 pm
by BUNDERA
ohh yeah and you can activate hi-range 4x4 (the electronic button that controls those actuators not the low-range lever) while moving. THE Hubs MUST be LOCKED in though. I have never had trouble even at excessive speeds :)

Nick