Plenum + clean throttle = troubles
 

First of all hello to all :) and greetings from the other site of the world ;)

I drive ^ g35 coupe 2003 and lately I've purchased plenum spacer (Motordyne 5/16 iso thermal).
During the installation I tried to be extremally carefull and with plenum I assume everything went well.
During the operation I've decided to clean throttle body (didn't know it's so tricky work in Infiniti - have done it couple of times previously in different cars and nothing bad ever happened).
After fixing everything to its place I've tried to run the engine - and here we are with my troubles... :

Car starts (RPM around 1,8k) but quickly engine shuts off (rotation constantly and rapidly falls to 0RPM).
Hitting the accelerator pedal makes thing worse, engine chockes much faster.

I've done everything I could:

1) removed plenum and put everything in place as it was oryginally - engine still stops, then I've put plenum once more - car behaves exactly thesame - that is why I assume it's not the reason)
2) put some more gas (just in case ;) )
3) rechecked multiple times all the connections and wireings
4) read all forums I could find - did'nt find anything symiliar
5) done troubleshooting - ECM returnet 0 0 0 0 (Just to check wether it works I've disconnected intake - it worked fine - ECM returned 0 1 0 2)
then I've reset ECM, and reconnected intake - ECM did not have any trouble codes: 0 0 0 0 )
6) tried to do the procedure of reseting throttle, but was able only to do first two steps of it (Accelerator Pedal Released Position Learning and Throttle Valve Closed Position Learning - actually don't know wether it worked), but I was unable to run Idle Air Volume Learning (Throttle Position Learning) - it requires running engine, and mine is not...

As for me the car acts like it is completely flooded with fuel - is it because of me cleaning the throttle body? Any suggestion will do - I was supposed to go to huge car meeting this friday - please HELP!

Solista (aka the Solist)

P.S. Don't laugh at my english - I've tried my best :P

Hi Solista,

I had the same problem awhile back. I'm never cleaning my throttle body again haha. I tried everything from reset procedures to simply giving it time to adjust back to normal, but nothing worked. However, recently I got very lucky. I decided to unplug my battery, hold the brake pedal down for 30-45 seconds, and leave it unplugged all night. The next morning, I hooked everything up and did a ECU pedal reset procedure. Before, my car was idling at 1000rpms. After, my high idle check engine light went away, and my idle was about 750rpms. Over the next days it returned to 650 RPMs and I haven't had a issue again. You may want to try this, as I was in your same situation before and it was very frustrating. Let me know how it goes!

-Sean

Edit: I may have misunderstood your problem. However, give it a shot and report back. I'll help you troubleshoot from there.:D

^^^ i would try that and make sure your Mass Air Flow Sensor is clean as well.

Check to make sure everything is plugged back in, missing electrical connectors can cause problems.

Did you check the butterfly was actually actuating like the throttle reset instructs to do?

It's also possible that you've got an air leak, a hose left off or incorrectly connected somewhere?

Did you remove the throttle body to clean it?

Ya, I did remove it..

problem still exists, I've checked throttle body wether its working at all, here is the movie with intake taken off.
It seems to me that throttle is ok.

About things to connect during install, I've marked them in red, the orange one is the pipe I've put valve in:
https://lh3.googleusercontent.com/-M...2520valve2.JPG
except that the only thing to connect is the electrics of throttle and the pipe going to intake (have no idea how You call it in english :/ )

I am pretty sure I have a fault air somewhere, just can't find where...
Any ideas how to check it? The engine stalls and stops in 5 sec, not an enough time to check anytking...

thamn...

I wish I could help! If you have checked everything and then double checked it. I think the problem by be in the throttle body. Something is either missing or broke on it.. I have heard that throttle is very sensitive and cleaning it can cause the problem..

I need to have mine cleaned as well, but I will take it back to the dealership.. I have the 5/16 spacer and mine idles kind of high as well. So I understand ya pain

So let me just get this straight. When everything is hooked back up, I.e. the MAF, intake tube, air box, filter, hoses etc, you start the car and 5 seconds later it shuts off? To me it sounds like there is a underlining problem that may have come about from the work you did. Do me a favor. Hook everything back up, and take another video of you starting the car. That will help give me a better idea of the situation. Also, are you throwing codes?.

-Sean

no codes, ECM stays clean...
Yap engine shuts down, the rpm decrease continuously to 0 - it takes arount 5sec

S.

If there's still power hooked up when you disconnect the throttle body it messes up its settings contained within. And the video you posted, with the MAF not hooked up the engine will have a hard time running regardless. With everything hooked up, try starting the car and give it a little throttle for about 20-30 seconds, enough to keep it running, then slowly release the gas pedal and see if that does anything. If the relearn procedure doesn't work then you will have to take it to a dealer and have them reset it, providing the TB is good.

the video above was just confirming that the throttle is working. I am aware that it causes troubles not having intake plugged.

Lots of new info about the case:

These are the movies I've made today, showing how does car work:
without my participation (trying to reach idle):

manipulating acceleration:

And now the clou of today's battle:
I thought of an air leakage on the throttle seal (don't know if that's the good word for it), so I've made myselve a seal made of dense carton paper - nothing changed in behaviour of the car.
Then I've unplugged electricat control unit of throttle and started engine once more.
It WORKED!!!!

(of course kinda harsh, but still, around 1k rpms but stable).

In conclusion, the engine is fine, the plenum spacer work is fine, seals ar OK, the problem is with throttle.

Infiniti likes to be unavailable, so we have to deal with rivets:
https://lh6.googleusercontent.com/-X...2/IMG_7628.JPG

couple moves with drill and we get:

https://lh6.googleusercontent.com/-q...2/IMG_7630.JPG

https://lh4.googleusercontent.com/-c...0/IMG_7634.JPG

Does the potentiometer work?
Max:
https://lh3.googleusercontent.com/-a...0/IMG_7631.JPG
Min:
https://lh5.googleusercontent.com/-Q...0/IMG_7632.JPG

But why does it need 4 pins? Usually potentiometer needs only 2...
Did not expect that:
https://lh6.googleusercontent.com/-R...0/IMG_7635.JPG

--------------------------

to sum up: mechanically there is nothing to be broken inside the throttle, electrically mine suits range given in service manual, so what the hell...

Still, I'm sure that throttle is the problem, but how the hell is that possible?

S.

Erm, so the very first video you posted, did you touch the throttle at all?

If you turn on the ignition, wait for the pre-stated time, and off, does the butterfly operate on it's own?

Sounds to me like you messed up your throttle body. It happens to a lot of people who clean their throttle body.
Attempt the idle air relearn procedure again. If it doesn't take then your TB isn't good.

Case solved: flowmeter was in reverse...
thx guys...

On the TB? is this something that can be turned round when cleaning or something?