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Help!!! Car revs to 7k after startup immediately!!!

Old 10-04-2018
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Help!!! Car revs to 7k after startup immediately!!!

Iím gonna start off with saying I appreciate any thoughts and ideas...... so I have an 07 civic ex 5 spd, wife was driving on highway in construction Zone, hit a rock that was left in the highway!!! *******s!!! The rock went right under the car from front to rear. So fortunately Iím a tow operator and was Able to get car to my shop, put it on the lift had broken radiator due to front subframe being tweeked a little bit, replaced vacuumed filled no air pockets, start it up and the rpms shoot right up immediately, pushed it out and left it for a bit.
Started messing with it again today started it up and it was the same, so I had my buddy outside and moved the intake box cover with the maf sensor and the idle jumped down to 3500 surging and a weird smell out the exhaust like propane? So anyway I had a brand new maf delivered along with an oem Honda throttlebody installed both... does the same thing.... then I smoked the intake for maybe cracks and vacuum leaks and it held pressure fine... so here it is guys please help Iím stumped!!
Thanks,
Joe
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Old 10-04-2018
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Re: Help!!! Car revs to 7k after startup immediately!!!

I'd say to take everything off down to the throttle body (TB), and make sure the TB plate is closed all the way and that all vacuum lines are seated properly.

Is your throttle body drive by wire or old school cable?

It electronic drive by wire, then make sure the ECU is telling the TB to be fully closed at idle (now that I think of it it may stay open a crack; I'm not sure if those electric TBs run an Idle Air Control Valve or not. But make sure it isn't open a lot).

Itf it is cable driven then make sure it is closed and find the rectangular port on the TB, on the inside of the TB right before the throttle plate. This is the port to the Idle Air Control Valve. If you cover part of the IACV and it idles normally then your IACV is stuck open and needs to be serviced.
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Re: Help!!! Car revs to 7k after startup immediately!!!

So unfortunately this car is the new technical drive by wire,
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Old 10-07-2018
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Re: Help!!! Car revs to 7k after startup immediately!!!

OK so If it were me I'd leave everything off down to the TB to monitor the throttle plate activity, unless there is a MAF sensor before the throttle plate. (leaving the air temp sensor plugged in but outside of the air charge is fine for testing)

I don't know those systems as well as cable driven TBs, but there must be a few sensors that tell the ECU when to open the TB. You will need to ask around and see which inputs the ECU needs to gather TB plate position.

Obviously there will be a Throttle Position Sensor (TPS), and MAF which will need to be checked.

Perhaps send a PM to Ezone, he is the master OEM parts expert around here... I'm really just an aftermarket rice Mod =D.
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Old 10-07-2018
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Re: Help!!! Car revs to 7k after startup immediately!!!

Throttle blade is usually spring loaded to a slightly open position when power is lost (default)
APP (Accelerator Pedal Position sensors) is what controls throttle, monitor APP A and APP B, compare to TPS A/B and actual throttle opening %
Wait, just key it up and watch the throttle action as someone works the gas pedal for you.

I would have kinda expected some large vacuum leak to cause it to rev, but....
Did something get wedged in the throttle? Gas pedal broke? Floor mat on pedal?
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