View Poll Results: Who did the IAVC Bypass??
I did it.
15
51.72%
I did not do it.
12
41.38%
My IVAC shorted out my ECU before I could do it.
2
6.90%
Voters: 29. You may not vote on this poll
Who did the IAVC Bypass???
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 1,329
From: South Jersey
Who did the IAVC Bypass???
Just wondering if this is something everyone has done or just few? For those that did it, did you replace the two hoses with one longer hose to bypass the IAVC or just connect the two hoses? Any problems after doing the bypass? If you don't do it, when do these leaks start--after 100K miles??
Thanks--with only 83K on the I30 not sure its worth doing it.
Thanks--with only 83K on the I30 not sure its worth doing it.
Last edited by sascuderi; Mar 13, 2012 at 12:02 PM.
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 1,329
From: South Jersey
yes ..could be IACV...it is where the hoses that supply antifreeze are disconnect from the IACV to prevent the fliud from leaking into the electronics and shorting out not only the IACV but the ECU.
Member
Joined: Jan 2012
Posts: 229
I removed both hoses and ran a new hose from where the inlet came from and where the outlet went to. When I started the car when it was warm sometimes it would shut right back down or stutter for a second and after that idle perfectly. After I did this I no longer had a problem with that.
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 1,329
From: South Jersey
I removed both hoses and ran a new hose from where the inlet came from and where the outlet went to. When I started the car when it was warm sometimes it would shut right back down or stutter for a second and after that idle perfectly. After I did this I no longer had a problem with that.
Any others interested in voting??? I know we have more than 7 members on the org!
That mod is called 'coolant bypass' and has nothing to do with the IAC Valve itself.
I've done the coolant bypass for free. Just re-route the hose from the tb back to the male end of the pipe below it. simple
I've done the coolant bypass for free. Just re-route the hose from the tb back to the male end of the pipe below it. simple
Spacer kit not needed for the mod...
My understanding of why coolant is cycled around the Throttle Body is to use the heated fluid to warm the TB in sub-zero temperatures so it doesn't stick. Right? Wrong? IDK for sure, really. There's some funny in the idea of using something called "coolant" in order to heat things up... but there it is.
NWP gives you this adapter so you can easily disconnect the inlet and outlet hoses that go to the TB, which is nice and all, but not required for phenolic spacer installation. It also leaves a lot of rubber hose lying around.
An alternative is to simply loop one of the hoses back around. Same net effect... less rubber. Here's a picture:
I live in Upstate NY, which only sees 1 or 2 sub-zero days a year, so I'm not really worried about that.
As to performance increases because of cooler air... who knows? I've got spacers, you see.
NWP gives you this adapter so you can easily disconnect the inlet and outlet hoses that go to the TB, which is nice and all, but not required for phenolic spacer installation. It also leaves a lot of rubber hose lying around.
An alternative is to simply loop one of the hoses back around. Same net effect... less rubber. Here's a picture:
I live in Upstate NY, which only sees 1 or 2 sub-zero days a year, so I'm not really worried about that.
As to performance increases because of cooler air... who knows? I've got spacers, you see.
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 1,329
From: South Jersey
I always thought that the coolant circulates in the IAVC to help set the idle speed. As the coolant temp goes up, the IAVC lowers the idle speed. No? Or is it just used to heat up the throttle body?
I almost did the coolant bypass myself by just connecting the hoses
together with a splitter. But didn't know what the consequences would be
so i left it alone.
Newbie - Just Registered
Joined: Feb 2013
Posts: 14
From: Alaska
When you do the coolant bypass, you should, in my opinion, cap the nipples on the IACV in the event your internal seal leaks you won't have an intake leak causing erratic idle.
I bypassed my IACV with a single hose.
I bypassed my IACV with a single hose.
Surprised me and made me laugh to see that old picture re-posted here by MrEous. Sometimes I miss how active I used to be in this forum.
Last edited by Rochester; Feb 23, 2013 at 04:38 AM.
Senior Member
Joined: Jan 2003
Posts: 1,446
From: California
Do I have to take the Throttle Body off? (it seems like I have to ... )
Any other suggestions?
Thanks!
Senior Member
Joined: Jan 2003
Posts: 1,446
From: California
Well, indirectly, yes.
The direct cause is a failed (= shorted) motor wiring in the IACV, causing too much current to be drawn from the ECU, which leads to the Mosfet in the ECU to fail/fry. Unfortunately, Nissan designer never thought of using a fuse to protect the ECU.
Most of us think that the coolant, or rather a coolant leak in the IACV, is a major reason (but not the only reason) for the IACV motor shorting.
There are several solutions to this problem .... search for "IACV" or "ECu".
The direct cause is a failed (= shorted) motor wiring in the IACV, causing too much current to be drawn from the ECU, which leads to the Mosfet in the ECU to fail/fry. Unfortunately, Nissan designer never thought of using a fuse to protect the ECU.
Most of us think that the coolant, or rather a coolant leak in the IACV, is a major reason (but not the only reason) for the IACV motor shorting.
There are several solutions to this problem .... search for "IACV" or "ECu".
Senior Member
Joined: Jan 2003
Posts: 1,446
From: California
Need advice re. Coolant Bypass
I am trying to do coolant bypass for my 2000 SE. My understanding is that I have to remove the Airbox. Do I have to also remove the "cross-member" to which the the MAF housing is attached on one side, and the "hose" leading to the TB on the other side? If so, what's the best way to do it?
There is a lot of stuff connected to this cross-member, so removing it looks like a lot of pain .... that's why this post.
I appreciate your help and suggestions.
Senior Member
Joined: Jan 2003
Posts: 1,446
From: California
One more thing: My mechanic refused to do the throttle bypass for me. He claims if he does that, the IACV will overheat and fail.
Is he right? Anybody has experience with IACV failure after doing a coolant bypass ??
Is he right? Anybody has experience with IACV failure after doing a coolant bypass ??
There are way too many people that have done this to prove him wrong.
Member
Joined: Oct 2009
Posts: 140
From: Birmingham, AL
Has anyone ever tried using the coolant lines on the TB to actually cool the air? For example, run the incoming coolant line through a separate fluid cooler before going to the TB? or maybe even a closed system using an auxiliary 12v pump? Of course this is after the MAF, so such a mod would require engine management.
also, there is something called non-conductive coolant that is used in computers.
also, there is something called non-conductive coolant that is used in computers.
Last edited by 2003MaximaMan; Aug 4, 2014 at 01:20 PM.
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