Hesitation

B

bluestreakrem

Member
Car
FX35
My 2009 FX35 hesitates when getting back into the throttle after a turn. It's always done this but seems to be getting worse as the car ages now with over 60K on the car. The hesitation feel is similar to what happens if an accelerator pump linkage is out of time or not hooked up on a carburarted engine. I beleive it's a lean fuel condition and has nothing to do with the tranny or gear position. There is no hesitation when the engine is cold and as such, I'm assuming the ECU is running a richer fuel map. When the engine comes up to temp, the fuel map probably changes to a normal map and the map is so lean (thanks EPA), hesitation occurs just as it comes on the throttle. I see this happen on motorcycle ECU fuel maps after an air flow change is made to the engine. If breathing is increased you need to add more fuel. Some ECUs have an "accelerator pump" feature which mimics a carburators accelerator pump principle by increasing the air fuel ratio for a short period of time, when a certain percentage of throttle is added. This eliminates lean fuel induced hesitation.
I've had the ECU reflashed for a shifting issue about two years ago but it didn't improve the hesitation issue.

Anyone else notice hesitation on thier ride?

Any suggestions as how to fix it?

Are there any after market fuel coorection modules (like a Dynojet Power Commander for motorcycles) that will allow me to alter the A/F ratio?
 
Get the 2nd update done like what Rip linked to above.

Another thing to do is clean the throttle bodies. At that mileage yours probably is filthy as hell. Mine looked like shit at 40k miles. It caused hesitation and poor driving character

---------- Post added at 05:16 PM ---------- Previous post was at 05:15 PM ----------

Follow my diy guide I made here in the diy section for throttle body cleaning
 
Fire0nic3FX said:
Get the 2nd update done like what Rip linked to above.

Another thing to do is clean the throttle bodies. At that mileage yours probably is filthy as hell. Mine looked like shit at 40k miles. It caused hesitation and poor driving character

---------- Post added at 05:16 PM ---------- Previous post was at 05:15 PM ----------

Follow my diy guide I made here in the diy section for throttle body cleaning
Click to expand...

Would this thread also apply to cleaning the throttle bodies on the 50?
 
If you were having a lean condition that was different or a change from previous, you would have a check engine light come on, I would also recommend getting the flash programming done....
 
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