hesitation when pressing gas pedal

THE NEW GUY · #1 10-26-2011, 02:04 PM

Hi everybody. My SVX shows some hesitation when I press the gas pedal to change lane and pass somebody. This hesitation last 2 or 3 secs, after that, car pushes hard and show all the torque. Do yo think temperature going down may affect? Any ideas anybody? No CL. New air filter (K&N): no change.

michael · #2 10-26-2011, 07:29 PM

Try cleaning the mass airflow sensor and getting on oem air filter.

THE NEW GUY · #3 10-28-2011, 08:05 PM

news about this issue:
I´ve just verify that the hesitation is just until rpm´s get 2500rpm. from that point, the car push really hard. I suspect this is because of the firing advance.

Sean486 · #4 10-28-2011, 08:19 PM

Quote:

Originally Posted by THE NEW GUY

news about this issue:
I´ve just verify that the hesitation is just until rpm´s get 2500rpm. from that point, the car push really hard. I suspect this is because of the firing advance.

IS it a 92? It could be that it needs the old bead crush mode.

http://www.subaru-svx.net/forum/show...ght=bead+crush

michael · #5 10-29-2011, 05:53 AM

Check for ECU Codes too.

http://www.svx-iw.com/svxiw/article/...php?article=78

btw: did anyone notice the first sentence in this doc? hint, transmission.

THE NEW GUY · #6 10-29-2011, 04:06 PM

I have no CEL on.
What is it "the old bead crush mode"?

Crazy_pilot · #7 10-29-2011, 05:35 PM

There is a noise suppression bead on the ECU circuit board. The SVX had a hesitation issue when it was first sold, and the factory fix was to take a pair of pliers and crush that little bead. There's a thread on it, and a How-To page.

michael · #8 10-29-2011, 05:35 PM

Sean posted a link ^^^^

Sean486 · #9 10-29-2011, 07:00 PM

Quote:

Originally Posted by THE NEW GUY

I have no CEL on.
What is it "the old bead crush mode"?

Sorry that was supposed to read "mod" not mode. Damn smart phone.

david_12121 · #10 10-29-2011, 08:31 PM

it doesn't seem a problem they way you say it...mine is kinda the same
when you step on it in 4th, it can't push that hard so it waits to make sure you wanna go fast then downshifts and you'll be gone...process takes 1-2 secs!
it's just the way most automatics are...
again it might not be this but mine "hesitates" too!

THE NEW GUY · #11 10-29-2011, 11:02 PM

to David 12121: theres no kick down in the process... I´m in Power mode all the time. This hesitation is present in every gear but its more noticeable at 3rd or 4th or when cold, when you can feel almost three steps of torque improve before reaching the 2500rpm point, where it really pulls. When hot, only the 2500rpm piont is really noticeable. I would say its mapped on the chip...
to crazy pilot: so I have to remove the ECU, identify one resistor and crush it with a plier? is it the bead crush about? So I dont need to change the chip?

michael · #12 10-30-2011, 05:58 AM

Did you check to see if you have old codes stored? Sounds like you may have a sensor on it's way out.

THE NEW GUY · #13 10-30-2011, 07:16 PM

Quote:

Originally Posted by michael

Did you check to see if you have old codes stored? Sounds like you may have a sensor on it's way out.

I did not have time to check stored codes but I did remove the throtle body and clean it deeply. bypass valve too. Control of iddle speed is way better now... but still hesitate. I've discard relations between hesitation and induction valve by confirming the operation of the induction valve in different moments of the hesitation. (vacuum meter connected to the induction solenoid). By the way, I've got to say that the induction valve does not activate the iris at speeds over 4200rpm's. As a matter of fact, the induction solenoid was activated only when the torque of the engine is very required at low rpms and stay on until you release the gas pedal or the engine reaches the exigency level demanded by the gas pedal. Tomorrow, I'll read stored codes and try to replace the O2 sensors.

oab_au · #14 10-30-2011, 08:35 PM

Quote:

Originally Posted by THE NEW GUY

I did not have time to check stored codes but I did remove the throtle body and clean it deeply. bypass valve too. Control of iddle speed is way better now... but still hesitate. I've discard relations between hesitation and induction valve by confirming the operation of the induction valve in different moments of the hesitation. (vacuum meter connected to the induction solenoid). By the way, I've got to say that the induction valve does not activate the iris at speeds over 4200rpm's. As a matter of fact, the induction solenoid was activated only when the torque of the engine is very required at low rpms and stay on until you release the gas pedal or the engine reaches the exigency level demanded by the gas pedal. Tomorrow, I'll read stored codes and try to replace the O2 sensors.

The valve between the two halves is normally open, to close at 2200 rpms to form the Inertia system. This systems torque peaks at 3200 till at 4200 the valve opens to join the two halves together, to allow the Resonate system to take over, peaking the torque at 4800.

This system won't cause your problem.

Harvey.

THE NEW GUY · #15 11-01-2011, 07:47 AM

Ok guys. I should check stored codes before posting this.
I have the following codes:
32: copilot's O2 sensor
37: pilot's O2 sensor
28: pilot's knock sensor (but is new, bought in amazon))
14: injector 1
56: EGR valve (but I just replace the EGR plastic pneumatic valve and disassemble and clean all the system, and replace all the vacuum hoses)
23: MAF abnormal voltage

I'll change the O2 sensors this week... then I'll let you know.