IACV/TPS/ECU replacement: slightly high idle & low timing

[rgk]

IACV/TPS took out the ECU. Replaced IACV, TPS, and had the ECU repaired.

Now getting an idle around 850-900 in park, and timing is 5-8 degrees.

Short term fuel trim is -10% per bank (rich condition?).
Long term fuel trim is 0% (needs drive cycles?).

Performed idle relearn several times with no success.

Checked for vacuum leaks, properly set TPS per FSM.

Does the computer have to OK all datasets (EVAP, emissions, etc.) via completed drive cycles before it will idle correctly or even perform idle relearn?

Cleaned out throttle body with IACV removed. Perhaps I dislodged some carbon and am now letting in too much air? There is still some carbon left on the sides that I could not clean. Perhaps clean this?

Any ideas? Thanks.

[rgk]

SOLVED!

They really mean it when they say you have to drive the vehicle for ten minutes before conducting the idle relearn procedure. This was one of two things I did differently when it finally worked. The other thing was to toggle the a/c on and off a few times.

On my 10-minute drive, I made sure to fully open and snap the throttle shut a few times, and tried to drive in a variety of conditions (fast, slow, idle).

Idle is ~750, and ignition timing is 15 degrees. Perfect!

[01pathfinder7]

Can you explain the reset procedure steps? I used it idol at about 760. Now sits around 775-800 after removing throttle body as well. Change a vacuum line too a very small one off the front of the engine with a very slightly larger diameter hose. I'm blaming that at the moment but would like to try a re teach

[rgk]

Which engine do you have?

[yngw13]

did you have to remove the upper plenum?
Im about to embark on replacing the IACV.
Was your battery disconnected during the removal?

[01pathfinder7]

It's the 3.5. I've seen it idol at 750 a few times since but once warmed up and foot off the clutch in neutral it's sitting at 850-900. I think it needs a re teach just not sure how

[rgk]

did you have to remove the upper plenum?

I suppose I didn't have to, but I've done it so many times now that it was easier for me to remove it than struggle to gain access to the upside-down IACV bolts.

Was your battery disconnected during the removal?

Yes. I also had to remove the ECU and have it repaired.

[rgk]

01pathfinder7: here is the link to the relearn procedure: http://nissanhelp.com/diy/pathfinder/pr ... arning.php

Remember to warm up the car by driving it a minimum of ten minutes before trying it.

[Brian VT]

Lots of great info. on this site!
I've read several posts that mention the IACV taking out the ECU.
Will replacing the IACV now (110k miles on my 2000 PF) prevent this from happening or is it a random event that is beyond our control?

[Brian VT]

Also, is it safe to wait until I get a code P0505 to tell me I should replace the IACV ?
I'm doing a timing belt/water pump/etc. now so don't really have an extra $170 at this time.

[Buzzman]

Lots of great info. on this site!
I've read several posts that mention the IACV taking out the ECU.
Will replacing the IACV now (110k miles on my 2000 PF) prevent this from happening or is it a random event that is beyond our control?

If yours is a 2000 model Pathfinder, then I assume you have the 3.3 engine??!! If so, then you are fine.
This whole IACV problem only applies to the 2001 and newer R50's with the 3.5 engine.

[Brian VT]

Whew. I do have the 3.3
Thanks! I'll sleep better now.

[walkabout]

How can we tell if the TPS cause the ECU to fail?

[oldhess]

I have a 96 pathy and the throttle was sticking. I cleaned the throttle body and now I have the high rpm idle and when in gear get fluctuating rpms as well (no more sticky throttle though). Tried adjusting the tps. Tried leaving the negative battery disconnected to"reset" the ecm. It's throwing tps code, knock sensor and O2 I think. P0120,P0135 and a P05XX. Any advice? This is my hunting rig and I only have a couple more weekends to get this kitty purring again.

[sonnyc]

I have a 96 pathy and the throttle was sticking. I cleaned the throttle body and now I have the high rpm idle and when in gear get fluctuating rpms as well (no more sticky throttle though). Tried adjusting the tps. Tried leaving the negative battery disconnected to"reset" the ecm. It's throwing tps code, knock sensor and O2 I think. P0120,P0135 and a P05XX. Any advice? This is my hunting rig and I only have a couple more weekends to get this kitty purring again.

You may have to take it to the dealer to have it reset. I tried everything I cleaned my throttle and replaced the distributor and ended up with high rmp. I did the relearn steps many times without success. It finally worked whenK took it to Nissan

[oldhess]

Thanks for the reply, do you know what the dealer does to fix it. I mean there are Consult II emulators you can buy for cheaper than taking it to the stealership.

[sonnyc]

They adjusted a bit of stuffs but I don't recall exactly. They spent about 2 hrs and they also did a bunch of tests?? It was $160. I think it's worth it since it got the truck running really smooth now and I didn't have to buy some tools and hope to emulate the consult 2 machine or spent alot of time to adjust and guest.