Peter

I notice that my car hesitate (surging of power or a hunting for power ) between 2,500-4,000 RPM while attempting to accelerate in a smooth fashion.

The car lunges and hesitates all while the gas pedal is being pressed ever so gently or even held in one position.
The car can't seems to find a place where it wants to take off smoothly. It

It feels like it may be starving for fuel, air, or spark.

My question is this normal or abnormal on the 350Z? The car is automatic and with an APS TT.

Thank you
Cesar
Orlando Fl

 

Cesar, peter doesn't come to this forum. He hangs out on 350z motoring. That being said aps is closed until 1/17/07. Your problem is not normal. Try checking the crank angle sensor connection. Unplug it and reconnect it then see if that helps.

 

Can't be certain, as I am not in the car myself, but it does sound like engine detonation. I hope you are not pushing it if the hesitations continues whenever you attempt to boost.

I would take it to your shop that did the install and get them to check out the EM system and the tuning.

G
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doesn't sound like detonation to me, it sounds like missfire or missing. Check all your spark plugs and check that the coils are connected to wiring properly.

 

sounds like vtec to me.

 

it sounds spool hesitation, does it do that on WOT? if it doesn't then it's normal, but i would take it to the guy who did the install and check it.

 

more info needed...are you monitoring A/F when it hesitates?, is this partial throttle? WOT? full boost?

 

I could be wrong, and I hope that I am; and as Todd had indicated, more information is needed to do the diagnosis from afar.

In most cases, if it is because of faulty spark plugs and/or coil the misfire can be replicated with open throttle and transmission in park/neutral.

The ECU could be responding to an over lean A/F mixture reading; your engine management could be retarding timing, as it is detecting same. Pulling out your spark plugs, the condition will afford you tell tale signs on the condition of the engine.

In any event, if you are driving and you accelerate and the hesitation reoccurs, release the throttle immediately; you may try to do it a second time and should the hesitation reoccurs release the load and take it back to the installer; or check if your fuel delivery system/EM is operating normally.

The safest bet would be to absolutely not attempt to boost the car till you resolve the matter.

Good Luck

G
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my only other suggestion is a leak in the exhaust manifold gaskets or somewhere close to the turbo

 

It is very hard to diagnose this when your a/f is good and you get no codes. I've seen this happen a couple of times. Nobody I know has been able to figure this out.

 

I have this same problem on my Z and I'm not running any FI. There is no misfire as far as I can tell cause I can't hear anything but the car start hesitating progressively getting worse and I doesn't stop unless I remove my foot from the gas pedal.

 

more info needed...are you monitoring A/F when it hesitates?, is this partial throttle? WOT? full boost?

I do not have a A/F on my car but, according to my tunner is running rich (11.9) also is only doing it at partial throttle only.

Thank you!
Cesar

 

Cesar I thought you told me high 10's to 11.5. But your a/f will be leaner at part throttle.


jmr0311 did you ever find out what was causing your problem?

 

Could be faulty coil or injector.

 

No, I haven't found the root cause of my problem yet. I replace new plugs a couple of hundred miles ago, I've being wondering myself if I have a faulty coil too.

 

I'm having the exact same thing on my car. I am throwing a code for the Crankshaft Position and am working on getting new sensor and wire to see what happens. I haven't gotten to hook the laptop up to the UTEC, but when I do I will datalog it and post....

 

If its not the CAS then I would say plugs.

 

It was one of the spark plugs and a leak on one of the gaskets on my APS test pipes.

No the funny thing is that I just trade the car for an 2006 6SP no more 2004 5 auto YEAH!!!!!!!!!!!!!!

Thank You again!!!!!
Cesar

 

I still have the APS TT for my old, but I am contempleating on selling it and get the JWT TT for the my new 2006. Looks like the custumer support on the JWT is better that the APS. Any sugestionds on what route I should take, any advices will be highly appreciated.

THX
Cesar

 

keep the aps...not worth trading, almost identical kit, except the aps is more classy (better design)

TODD