Throttle body(Drive-by-wire) idle issues

[Andy]

Hi there, I've installed an Acura ZDX throttle bottle a few weeks ago and still been having this 'one' problem that I hope someone can shed some light on ><"

Problem:
"Almost" every time when I let off the throttle the car feels like I hit the brakes. It has basically made my car very jerky :S


Other info:
*Idles at 1,500RPM on cold start, Idle slowly comes back down to stock as the coolant temp rises, when coolant reaches normal temperature (80*C) the idle is at OEM settings(however when I rev it the idle comes back down then jumps to 1,500rpm then comes back down to normal idle)

*Was installed about 3 weeks ago

*no CEL light, no codes

*The ZDX throttle body was purchased brand new(so the 'set screw' is on OEM settings and hasn't been touched)


Methods already tried:
*Disconnect battery for 10 sec-Turn key to II position and wait for 10 sec-Start Car-Rev to 3000rpm for 7 minutes-Let car idle for 15 mins

*Disconnect battery for 10 sec- Start car- Rev to 3000rpm until coolant temp reaches 90*C(194F)(also tried reving until radiator fan comes on)-idle for 5 mins

*Saw the throttle body manual recalibration prodcedure on the 8th gen civic forum however I do not have a CEL code


Car Specs:
Honda Accord Euro, K24a3 engine, RBC, Injen intake, P2R IM gasket, P2R TB spacer, P2R TB gaskets, ZDX throttle body(drive-by-wire)


** Random Hypothesis: I think that the jerkyness is possibly because of an idle issue, OR because I changed from a 60mm throttle body to a 78(inlet)-70(outlet) throttle body???


Any help would be appreciated thanks and thanks for reading lol :D

[Fredoops]

Does the IM and the TB match up perfectly (as in the IM inlet and TB outlet), IM inlet should be 1-2mm larger then the TB outlet iirc.

IIRC the RBC's inlet is 60 odd mm isnt it? so you'll need to bore it out

Edit: also

do you have exhaust mods? as in header/cat?

because when I just had CAI in the Euro, before the new headers were put in, the car did deccelerate a lot faster off throttle.

[dougie_504]

Idle sounds fine. Is the cable too tight?

[Fredoops]

Idle sounds fine. Is the cable too tight?

dont think there is a cable with Drive by wire is there?

[dougie_504]

No idea TBH, just throwing it out there lol.

Cables so much better IMO, electronic or hydro = issues waiting to happen!


Is there a TPS to be re-calibrated?

[Andy]

@Fredroops Yeah the RBC inlet is 60mm, however the throttle body spacer I have is 'tapered' down from 70mm to 60mm(is kinda like / \) so the throttle body goes on the 70mm end and the RBC goes on the 60mm end. In this case do you think this may be be a problem? But I'll look into getting a machinist to port match the RBC and TB spacer with the TB.

**dont have headers/cat "yet", soonish I hope. Impulsed bought the RBC and TB...(amateur mistake)


@Dougie_504 'Drive-by-wire' Throttle bodys dont have a tps sensor. thanks anyways

[Fredoops]

With the TB Spacer it should look something like this

TB : \ /
TBS: \ /
IM: \ /

The inlet should always be 1-2 mm more than the outlet iirc to make sure there's no disruption.

Also, is the RDX Dbw motor runs the same voltage as the CL9's?

[Andy]

Haven't measured voltage yet, as i didn't think that would be a problem as some other forum said that manual TB(DBW) calibration is not needed if there is no CEL code,,, but mainly because I don't want to stick the volt meter pins into the wires :S, but I'll try and measure the voltages of both TBs, to see if there are any significant differences

[Andy]

Okay, I measured across THL1 and SG, then did the same thing for THL2

Stock throttle body read THL1= 0.66V, THL2=1.53V

ZDX throttle body read THL1= 0.62V, THL2=1.49V. (My volt meter cannot read more than 2 decimal places)

You reckon the figures have a significant difference?

[Fredoops]

I dunno cause I'm not an electrician sorry