Weird idling issue....

[vish]

Hello all

Long time no post!

Finally got round to investing a bit into the old mk2 3vz and thought I'd run a weird issue past you all.

Had a funny idling issue in that the car would - sometimes - oscillate up to 2k ish and back to 1 then to 2 then to 1 - all when it is supposed to be idling at 7-800. So, I replaced the IACV with a used one from the states. This sorted the problem but, now, when I drive the motor, it idles OK accept when I come out of gears when slowing down - the car sometimes (maybe 30% of the time) tries to die. Can't see any noticeable vacuum leaks but shall look out. Do you think the replacement IACV is pish?

AFM has had issues and is being replaced with a used one from the states as well as the alt belt (hasn't been changed in a while and is squeaky!). Not sure if these will help but hopefully so.

Let me know your thoughts - might ask my pal at Arnies to price me up a new IACV if you guys think it might be that again.

Cheers

Vish

[aussiemr2]

Your original iacv probably had the pocvip mid done which keeps idle above 900
It's a known issue that causes the stall
The proper fix is to connect the Mrel wire from the Ecu correctly

http://www.twobrutal.co.uk/forum/sho...highlight=Mrel

[cdwood2010]

I've never had the stall issue. But I plumb a 3vz differently.

I run a 6mm pipe from the end of the acis to the IAC. Most people cap these off.

On the original cammy these two are T'd into the steering, so that when you steer left or right slightly the rpm picks up to cope with the steering pump load.

I would like to add the mrel to the wiring guide, as I'm becoming a big fan of all these additional bits on a swap. Bit late I know, but what the hell.

:)

C.

[Paul Woods]

Yep, the new ISCV will need to be modified or Mrel connecting up, either way works.

[vish]

Ideal gents. I shall have a look tonight. I prefer the pipe mod - despise wiring!

Chris - do you have a pic which shows where the pipe should go at the end of the ACIS, or is it pretty obvious (i.e. only one natural hole for it!)?

Cheers all

[cdwood2010]

I sure do baby.

Its fairly obvious. Its under the servo vacuum pipe on the acis:-



And it runs to the back of the IAC, you can just see it here:-



This is very low vacuum pressure, so no need for clamps. Just a 6mm (i/d) pipe pushed on each end, about 1m trimmed to size.

One thing that will happen, when the engine starts the rpm will blip up to about 1200-1500 and then settle back down again. I believe this is caused by the suction resetting the IAC, which is probably why i have never had an issue, or had to do the POCVIP mod. Paul Woods pointed out at JAE in 2013 that it should be capped. If you cap both ends (or just pinch the pipe) the startup is very different, the rpm's are static from the getgo.

Have a play, it might not be your issue. At least you have multiple solutions to tinker with here!

Chris.

[aussiemr2]

Just be aware that chris's mod probably works because it introduces a fixed air bypass between the ISCV and IAC

This pipe originally ran off a valve on the Camry cooling fan oil circuit and was used to idle up when aircon was turned on

I actually used this in conjunction with the original 3sge idle up valve to retain full aircon control on the 3vz swap

[cdwood2010]

Ah, i always assumed it was related to the steering as it interacts here on the Cammys:-

[Paul Woods]

It is for idling up when the PS pump goes full lock.

[vish]

Genius! Ran a 6mm pipe across those two and the idle was initially up at 1500 ish for a short stint but dropped nicely down. Couldn't take the car out because a) it's snowy and I'm in an uphill garage - wouldn't get it back in and b) the tyre place are complete idiots and cant fit tyres properly - full of slow punctures.

Will let you know how it goes.

Again - many thanks gents. Here I was thinking the 'new' IACV was duff/there was a big AFM issue etc etc. Nice to know it's a easily solved issue.