1cockyZ

iTrader: (46)

I installed a ported throttle body and did all the resets and it idles at 950. its a 73mm throttle body car drives fine just a little funny when cruising at low rpm and you drop throttle kind of jerky. and when you let off the gas the tach comes down to 1200rpm then to 950. anyone else have this problem or know how to fix it.

eat rice z33

iTrader: (11)

srry dont have answers but hows your power gain?

ktown z

iTrader: (8)

I had a over bored throttle body on my other ride and had similar problems. The first problem was the butterfly plate in the center of the TB did not fit correctly and there was a gap inbetween the butterfly and inner bore. Also it caused false readings with my thottle position sensor.

overZealous1

iTrader: (27)

^ what i was going to say. possibly also, the idle learn will set the throttle plate at a certain point, the point where the stock sized tb needed to be for correct idle calibration. if it gets set to the same point, you will be taking in more air with the larger tb. i would undo it, and don't do the throttle pos learn. just start it up and see what it does.

ACEMAN

iTrader: (29)

What OverZealous said. Also double check that you have it all sealed up. The problem area can be the bottom right hex screw not being tight enough.

I have a ported throttle body aswell, not sure how much of a difference it has made, but its on the car and no problems.

Good luck

Later
Aceman

1cockyZ

iTrader: (46)

To add some information I installed the tb with upper plenum removed and ported the upper plenum, and gasket matched it all. also if anyone has ever looked there is enough play that if you don't open the throttle blade and align the gasket and upper plenum and tb you will end up with a couple mm lip on one side, so i lined it all up for max flow. the stock throttle body you can see daylight around the blade top and bottom so i can imagine there is extra air flow causing my problem and it can maybe be recalibrated with a consult but the people at the dealership are less than helpful when the car is modified, as the techs knowledge outside of stock is nil. anyway maybe i will call proflow and see if i can score one of there stainless blades after a nice measure of the inner bore. aceman about the one hex not being tight enough i torqued all the bolts in steps to 80in/lb, and have smoke and map gas tested for vacuum leaks. actually found one in one of the center bolts as i have the aam spacer with o-ring washers so i rtved it up and no more leak. the problem was way worse before that idling at like 1250 and way jerkier driving around. but now i am at a point where i corrected the vacuum leak and did all the resets again, now the only problem i can point to is the fact the ecu needs recalibration for airflow around the blade so maybe a new blade is in order. so my question is does anyone know if the consult can recalibrate for that added idle airflow around the larger blade.

1cockyZ

iTrader: (46)

about the gains serious but dyno gains all around but i have pop charger, aam spacer, dc headers and full exhaust including hfc's so this was a possible bottleneck .

E K

iTrader: (10)

I had the exact same problem after I did my porting and gasket matching.

It's an issue with the computer/electronics of the TB. It gets messed up somehow when you port it, I think from the vibration. I've had it occur on 2 separate throttle bodies, and one had the problem develop after just opening it up.

Initially I thought it was an air leak issue, and even had proflow work on it for me (to give a better plate/chamber interface). But it didn't change a thing. I had them try and recalibrate the electronics for me, but then my idle went from 900 to 1400! And the car soon went into ECU limpmode, and I had to drive home goin 20 MPH, cars in back honking like crazy. I really wish the ECU limp mode would still give you some power, because it's quite a road hazard when you hinder even local traffic. Proflow does good work with the TB, but the electronics in the TB are very sensitive.

ACEMAN

iTrader: (29)

Trying to think back to when i installed mine.

Basically i installed the new throttle body and did a ECU reset like on the technosquare page and started the car leaving it idle of 5 mins.

After that everything worked fine and no issues have come up since. This was 3 months ago.

If you havent tried this, here it is, hope it helps.

ECU RESET PROCEDURE

Here is a quick way to reset your ECU. It is also known to clear codes thrown, and turn off the "Service Engine Soon" Light. It's a little tricky, but works.


1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.

2. Repeat the following steps (a and b) procedures quickly five times within 5 seconds:
--a. Fully depress the accelerator pedal (HARD).
--b. Fully release the accelerator pedal.

3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.

4. Fully release the accelerator pedal (while the CEL is still blinking)

5. Wait about 10 seconds.

6. Fully depress the accelerator pedal and keep it for more than 10 seconds.

7. Fully release the accelerator pedal (The CEL light will continue to blink).

8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.



Later
Aceman

E K

iTrader: (10)

I had done the ECU reset, the idle reset, basically everything. It was a TB computer issue. At one point I had 3 throttle bodies sitting around, and the problem was clearly reproduceable with swapping in the affected TB.

Z4Zoro

Not sure what the problem is.

Does the 350z intake/heads come ported/polished already? Because a ported throttle body will make no difference at all unless your intake manifold and heads are both ported as will to match. Everything is only as good as its weakest link.

Quamen

iTrader: (14)

Since it was discussed about a gap between the plate and the TB, does anyone know what the recommended tolerance is for plate to housing clearance?

Also, in order for the plate to close correctly, does the housing have to taper down to the plate size on both sides in order to allow the plate to rotate properly without hitting the edges or can the bore be the same diameter as the plate (plus the clearance tolerance) all the way through (straight)?