Re-routing AC Idle up vacuum hose Gen 3 Now with pictures

Re: Re-routing AC Idle up vacuum hose Gen 3 (nick12)

Mon, 03 Feb 2014 23:11:05 GMT

With vibration and age, even solder done well, can fatigue. Perhaps try these double heat shrink crimp connectors:

Raychem Duraseal

http://australia.rs-online.com/web/p/crimp-terminal-kits/4089681/

which should outlast the original wire.

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Mon, 03 Feb 2014 21:47:03 GMT

P E T E
FYI - I'm not a fan of those crimp plugs. I have had them fail due to vibrations in the past. I'd recommend getting one of these wiring looms from Jaycar if you run into any trouble: http://www.jaycar.com.au/productView.asp?ID=SY4069
Its cheap and worthwhile!

This also stops you from incorrectly plugging all the wires back in if you ever have to relocate the relay!

Thanks PETE. That does look like a good idea - I'm not a fan of using crimps either, prefer to solder and then heat shrink but in this case I had all of the materials at home and wanted to get it done fast.

I'll definitely keep an eye on it.

Re: Re-routing AC Idle up vacuum hose Gen 3 (P E T E)

Mon, 03 Feb 2014 09:37:10 GMT

FYI - I'm not a fan of those crimp plugs. I have had them fail due to vibrations in the past. I'd recommend getting one of these wiring looms from Jaycar if you run into any trouble: http://www.jaycar.com.au/productView.asp?ID=SY4069
Its cheap and worthwhile!

This also stops you from incorrectly plugging all the wires back in if you ever have to relocate the relay!

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Sat, 01 Feb 2014 22:45:23 GMT

All good mate. I'm getting the nipple welded onto my BOV joiner pipe this week so should all be back to normal.
Do the AC mod, took me around half an hour :)

Re: Re-routing AC Idle up vacuum hose Gen 3 (artymr2)

Sat, 01 Feb 2014 21:35:03 GMT

Apologies, I have given you a bum steer, the gen 3 in our car does have the nipple below the BOV. I have been playing with modifying a hot pipe but it is a gen 2, I must be getting old ....

I have all the bits to do the AC mod, just haven't had the time to do it.

Cheers

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Fri, 24 Jan 2014 23:20:25 GMT

Ok, so with all the effort Mrskylighter went to helping me fix this problem, it's only right I put up pictures on this problem was fixed.
Problem: After conversion from a NA to a 1995 Gen 3 3sgte, the AC idle up did not work properly due to a difference in electronics between the NA and Gen 3.

With the AC on, the idle dropped and the engine struggled (when the idle should actually increase).
With the AC off, the idle increased and the engine revved slightly higher than it should.

Hence, the AC idle up was not working as it should.
(The following is credited to Mrskylighter and will only work if the negative is being switched, not the positive. Also, for some strange reason the red wire on the AC plug was actually negative, and the black and yellow was positive).

This is the AC idle up (VSV) plug.

I cut the negative lead (in my case it was the red wire) and soldiered on about 200mm of wire to each side. I kept the colours of the wires the same to avoid confusion.

Put some heat shrink on to cover up my dodgy soldiering haha.

Crimped the other ends of the red wires with some male connectors.

Stripped back some of the black and yellow wire (didn't cut) and soldiered on a piece of wire. (Note: this was my positive lead.) Couldn't heat shrink this one so I put some tape on.

Put a crimp on the end of that one and hooked them up to the 5 pin relay.

Red wire, ecu end - terminal 86
Red wire, plug end - terminal 30
Black and yellow wire - terminal 85
Earth lead to body - terminal 87a

I also put an earth lead on...you can see it bolted to the body on the right in the picture above.

Finally, made it look legit haha.

All works fine after plugging the AC idle up plug back in :)

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Fri, 24 Jan 2014 20:04:03 GMT

Congrats! Glad it fixed your problem :)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Fri, 24 Jan 2014 19:09:20 GMT

Done!!! It works now like it should, idle increases when AC is turned on, then decreases when AC is off.

Nick, I did it pretty how you explained it above... I had a look at doing it in the boot near the ecu but was too much of a stuff around to find the right wires.
I'll post up pictures tonight :)
Now I just need to get a nipple welded on the BOV joiner.

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Fri, 24 Jan 2014 17:45:30 GMT

If you haven't started the wiring yet I would probably tackle it as follows.

Cut the neg/ground wire about 4-5cms back from the a/c plug and extend both sides of it to the relay.
- Connect the wire which goes to the back to the plug to terminal 30 on the relay.
- Connect the wire which comes from the ecu to terminal 86 which is the relay coil.
Tap into the pos wire and run to the relay. (no need to cut through it completely)
- Connect the wire to terminal 85 which the other side of the relay coil.
Make a short length of black cable up with a ring terminal on the end and connect this from a bolt on the body somewhere to terminal 87a on the relay.
Final step is to plug the a/c plug back into the a/c valve and see what happens.

I think a 5 pin relay, some wiring and assorted crimp plugs shouldn't cost much more than about $25-30 if you have none of it already.

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Fri, 24 Jan 2014 00:02:27 GMT

Sweet. Well then good to know the AC guys didn't stuff things up. Hopefully I've got some time tomorrow to give this a go. Chopping into the wiring is going to be the hard part haha

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Thu, 23 Jan 2014 23:26:02 GMT

Yep you can do the fix at the ecu harness instead. That's where I did it on mine.

You just need to decide where you are going to chop into the wiring.

Re: Re-routing AC Idle up vacuum hose Gen 3 (artymr2)

Thu, 23 Jan 2014 23:14:56 GMT

Have the same idle issue after the gen3 swap, have not gotten around to sort it. I understand it's the signal in the gen3 that the ecu receives is reversed. Is it worth applying a similar fix above to the trigger wire to the ecu instead of the valve itself? I guess the final outcome will be the same.

Cheers

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Thu, 23 Jan 2014 22:51:24 GMT

i believe the reason it happens is because the a/c amp in the early models puts out a different signal than the a/c amp in the later cars.
its the a/c amp that tells the ecu that he a/c is on via a/c pin on the ecu harness.

if you build the cheap relay above you will be sorted. this idle issue is not due to a fault, just a difference in electronics.

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Thu, 23 Jan 2014 22:42:02 GMT

Thanks Nick, you are a legend. Really appreciate it.
Last question, when you had this same problem (AC idle up) on your car (and I'm guessing you did a conversion too), was it due to the conversion to gen 3 3sgte and not the AC amplifier?
Just making sure it's not worth my while having a look at the AC amplifier.

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Thu, 23 Jan 2014 18:33:23 GMT

Okay this circuit diagram is the one you want to reverse the neg/ground at the A/C idle up valve.

Once again happy for someone to critique my design to confirm it works or simplify it.

So with the a/c switched off in the car the neg/ground will not be sent to the a/c valve as the relay will be energised.
With the a/c on the relay will not be energised. As a result of the normally closed relay the neg/ground will be sent to the a/c valve which will cause it to operate.

I will delete the earlier diagram so as not to confuse anyone who finds the thread in the future.

Re-routing AC Idle up vacuum hose Gen 3 *Now with pictures*

Re: Re-routing AC Idle up vacuum hose Gen 3 (nick12)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Re: Re-routing AC Idle up vacuum hose Gen 3 (P E T E)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Re: Re-routing AC Idle up vacuum hose Gen 3 (artymr2)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Re: Re-routing AC Idle up vacuum hose Gen 3 (artymr2)

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Re: Re-routing AC Idle up vacuum hose Gen 3 (MIDN1T3)

Re: Re-routing AC Idle up vacuum hose Gen 3 (Mrskylighter)

Re-routing AC Idle up vacuum hose Gen 3 Now with pictures