A little while ago I purchased a low milage Idle control valve, as I suspected mine had seen better days.

At first glance everything looked okay.

It wasn't until I compared them side by side that I noticed some subtle differences.

My question is, although they are different, can I fit the newer one without any issues?

The later one is the one that looks fairly clean as opposed to the grubby one I have just removed.

Unfortunately, only the newer of the 2 valves have any part numbers on it.

Pictures below....

http://www.importpartspro.com/2378140p10.html

https://conceptzperformance.com/nissan-oem-23781-40p10-iacv-idle-air-control-valve-aac-nissan-300zx-90-96-z32_p_573.php

Edited May 24, 20178 yr by AndrewG

Thanks Andrew.

 

Will I need a different gasket to isolate the the two ports? (as opposed to just the single square orifice of the original one?)

May have answered my own question, fortunately I have a spare.

 

http://www.importpartspro.com/ni30oemaavag.html

So, in summary.

It appears that the new, albeit second hand, will indeed fit without issue.

Why the difference? older/newer designs?

So, in summary.

It appears that the new, albeit second hand, will indeed fit without issue.

Why the difference? older/newer designs?

 

Who knows - maybe a different supplier or redesign during production.

 

Amazingly expensive in the UK:

 

http://nissangenuine.com/nissan/nissan-not-available-2378140p10/

 

Amazingly expensive in the UK:

 

http://nissangenuine.com/nissan/nissan-not-available-2378140p10/

 

Jesus! Hopefully my low mileage used one will be up to the job, only cost £45

Who knows - maybe a different supplier or redesign during production.

 

Amazingly expensive in the UK:

 

http://nissangenuine.com/nissan/nissan-not-available-2378140p10/

 

That part number isn't available. There seem to be several part numbers for that valve floating about, would need some clarification of compatibility.

 

http://nissangenuine.com/nissan/nissan-valve-assy-aac-2378140f07/

Edited May 24, 20178 yr by Joely P

That part number isn't available. There seem to be several part numbers for that valve floating about, would need some clarification of compatibility.

 

http://nissangenuine.com/nissan/nissan-valve-assy-aac-2378140f07/

 

The part# is valid, it is the part itself which is showing NLA on NG. It is however still available in the US with that part#.

There seem to be several part numbers for that valve floating about, would need some clarification of compatibility.

 

With this in mind, is the general consensus that I should or shouldn't fit the second hand unit?

I've checked the OHMS readings, and they tally with the manual.

Dave, the links I posted earlier show 23781-40P10 being sold for Z32 applications by two reputable vendors. Provided your

s/h part is serviceable you can fit it. Captain Slow is muddying​ the waters.

Cheers Andrew.. :thumbup1:

 

I'll fit it today and report back.

Prior to fitting the valve, I thought I might as well give it a good internal clean.

Considering the relatively low mileage, it was a tad sooty.

One thing I did notice whilst doing so, was the very free movement of the larger solenoid valve piston.

I mention this as the one on the existing did not move at all. (seized me thinks)

I'll know more when I fit the newer one I guess.

The part number I listed (F07) appears to be for an S13, it is essentially the same part but the pipework is different. The original part has 2 different manufacturers which are separated by 2 part numbers (you have one of each in your pic). One of them is still available in the UK which maybe cheaper than importing one if you really get stuck. Hopefully your used jobbie will do the business.

 

http://www.allcarpartsfast.co.uk/nissan/nissan-2378140p00-valve-assy-aac/

 

 

Have you got a replacement gasket for it? The same part number is compatible with both.

 

http://www.allcarpartsfast.co.uk/nissan/nissan-2378540f00-gskt-aac-valve/

Thanks Joel, appreciate the help and advice.

Luckily, I do have a spare gasket to hand.

So, after a fiddly few hours re assembling everything, DataScan looks like this...

To be honest, I'm not too sure what to make of it all really.

The only odd thing I did notice was that when my pesky misfire occurs, the RH O2 sensors drops right off and then jumps back.

Would this be a reaction to the misfire? or possibly the cause?

According to the picture/screenshot, your base idle is probably set too low.

AAC value needs to be a steady 15% @ idle.

 

try setting base idle to 850 rpm..this is usually ok for most 300's

Thanks Lymon, :thumbup1:

 

I will make the adjustments as you suggest either later today or sometime tomorrow.

I did set the base idle a little low at 600-650rpm to be honest.

According to the picture/screenshot, your base idle is probably set too low.

AAC value needs to be a steady 15% @ idle.

 

try setting base idle to 850 rpm..this is usually ok for most 300's

 

Well, after a bit of patience and a lot of adjustment, I finally got close to 15% @ idle.

Figure is very sensitive to engine temperature I found. (makes sense I guess)

 

Thanks again Lymon.. :thumbup1:

 

 

 

Still chasing my intermittent misfire though.

One thing I did notice again, was the correlation between the RH o2 sensor and the misfire.

The drop off of the o2 reading was instantaneous with the misfire, very in sync.

That's got to point to something specific, surely?

Still chasing my intermittent misfire though.

One thing I did notice again, was the correlation between the RH o2 sensor and the misfire.

The drop off of the o2 reading was instantaneous with the misfire, very in sync.

That's got to point to something specific, surely?

 

The O2 reading is likely a symptom of the misfire not a cause. I guess you have already checked the plugs etc already?

You can disconnect the O2 sensors, the ecu will run a means setting, no O2's are better than dodgy ones. As Dougal said its likely a sympton because of the misfire. Check the coil connectors and injector connectors again to make sure they are clean, then seated all the way home.

The O2 reading is likely a symptom of the misfire not a cause. I guess you have already checked the plugs etc already?

 

Hi Dougal200,

So far I have checked both the fuel injectors and the coil packs, both seemed okay.

As for the plugs, I did do a basic continuity test along with an insulation test.

Both again seemed okay.

May swap the plugs over from left too right and see what happens.

Fingers crossed.

You can disconnect the O2 sensors, the ecu will run a means setting, no O2's are better than dodgy ones. As Dougal said its likely a sympton because of the misfire. Check the coil connectors and injector connectors again to make sure they are clean, then seated all the way home.

 

Thanks Graham, I will double check the connectors again, although I have completely cleaned and greased them with dielectric grease.

You never know though.

Can't think of what else could affect just the one bank.

Hopefully it may be as simple as a failing plug.

Is there a way of checking the harness to both the injectors and the coil packs?

Say voltage or continuity?

If memory serves me right, I think Jeff once mentioned that there is a type of insulation that breaks down.

Check the ptu connections and cas plug too :thumbup1:

 

You can do a continuity test from the ecu end with the + probe and use some extra wire connected to the - probe and buzz through. The ecu pin out diagram is in the tech faq section or online manual.

I did have a pin issue on one of my injectors at the ecu end, in which i had to solder a jumper on the board as the track had burned out slightly, it caused my issue at the time.

Have you checked the injectors themselves? Free and doesn't take long. Maybe Ines a bit out of spec and throwing things about

Check the ptu connections and cas plug too :thumbup1:

 

You can do a continuity test from the ecu end with the + probe and use some extra wire connected to the - probe and buzz through. The ecu pin out diagram is in the tech faq section or online manual.

I did have a pin issue on one of my injectors at the ecu end, in which i had to solder a jumper on the board as the track had burned out slightly, it caused my issue at the time.

 

Thanks again Graham.. :thumbup1:

Checked the CAS connection, all appeared good.. no change.

Swapped out the TPU for my known working one.. no change.

:confused1:

 

Have you checked the injectors themselves? Free and doesn't take long. Maybe Ines a bit out of spec and throwing things about

 

Thanks also Stephen..:thumbup1:

I did a ohms test across all six and all came back good.

:confused:

 

So, at this point I decided to fit a spare set of old plugs, they are not the correct ones exactly, but I thought they would suffice for a test.

 

Guess what!.... No more bl''dy misfire!! :blushing:

Can't believe it as I had checked the originals several ways.

Could this be simply down the the plugs being over gapped? (I will need to check them)

Maybe one of them is just simply on the way out.