Gas Pedal Delay

juld0zer · 05-18-2014, 10:43 AM

i've pondered that possibility but eliminated it because it seems a bit bizarre for an engine to develop a vibration or harmonic issue at certain operating temperatures. It's not impossible because i know the engine does vibrate a lot. I have the plastic engine covers removed and to avoid losing the nuts/bolts, i just nipped them up on the intake collector. I pop the hood once a week and 70% of them have become loose by several turns.

Cant be a bad batch of knock sensors either because of the widespread awareness of the problem.

The other issue is it seems that most people are complaining about the lag in 1st gear only. Assuming that most folks are running stock intakes, i'm willing to bet that they are experiencing heatsoak of the IAT sensor - ie, ecu sees the air entering the engine as being hotter than it actually is; due to radiant heat influences from the headers, radiator airflow etc.

There is, without a doubt a difference in throttle response between oil at 90*c or less with coolant at 87*c or less versus oil and coolant temps above these approximate figures. The simple stab-the-pedal test shows this in a no load scenario. Someone on here datalogged the lag and it clearly shows a delay of several seconds between pedal activity and throttle body activity with VDC off during a 1st gear takeoff - this was done with IAT at 104f/40c which is definitely in the high territory. This is the lag that keeps you at the lights while the wanker in the bone stock Civic takes off.

I have experienced severe 'heatsoak' by intentionally using a different IAT sensor (one which reads higher, ie different resistance curve for those familiar) and it will affect you even when you're moving. Overtaking is scary. Gaining speed takes an eternity. Not fun.

I'm wondering, for those of you with remapped throttle tables - do you still experience the acceleration lag both on take off and in-gear acceleration?

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05-18-2014, 10:43 AM	#10 (permalink)
juld0zer Enthusiast Member Join Date: Nov 2012 Location: Sydney Posts: 428 Drives: 11 Nissan 370Z MB M6 Rep Power: 139	i've pondered that possibility but eliminated it because it seems a bit bizarre for an engine to develop a vibration or harmonic issue at certain operating temperatures. It's not impossible because i know the engine does vibrate a lot. I have the plastic engine covers removed and to avoid losing the nuts/bolts, i just nipped them up on the intake collector. I pop the hood once a week and 70% of them have become loose by several turns. Cant be a bad batch of knock sensors either because of the widespread awareness of the problem. The other issue is it seems that most people are complaining about the lag in 1st gear only. Assuming that most folks are running stock intakes, i'm willing to bet that they are experiencing heatsoak of the IAT sensor - ie, ecu sees the air entering the engine as being hotter than it actually is; due to radiant heat influences from the headers, radiator airflow etc. There is, without a doubt a difference in throttle response between oil at 90c or less with coolant at 87c or less versus oil and coolant temps above these approximate figures. The simple stab-the-pedal test shows this in a no load scenario. Someone on here datalogged the lag and it clearly shows a delay of several seconds between pedal activity and throttle body activity with VDC off during a 1st gear takeoff - this was done with IAT at 104f/40c which is definitely in the high territory. This is the lag that keeps you at the lights while the wanker in the bone stock Civic takes off. I have experienced severe 'heatsoak' by intentionally using a different IAT sensor (one which reads higher, ie different resistance curve for those familiar) and it will affect you even when you're moving. Overtaking is scary. Gaining speed takes an eternity. Not fun. I'm wondering, for those of you with remapped throttle tables - do you still experience the acceleration lag both on take off and in-gear acceleration?