sticking at 4000 RPM

[blackeagle113089]

While In drive, as I am driving I can seem to get it to raise past 4000 RPM. Such as when I push the pedal to the metal for passing someone, its sticking at 4000 rpm...any idea why?

[paranoidjack]

While In drive, as I am driving I can seem to get it to raise past 4000 RPM. Such as when I push the pedal to the metal for passing someone, its sticking at 4000 rpm...any idea why?

Although i probably couldn't help you anyway, you're going to want to give the year and model of your car, and maybe some more detailed situational examples.

[Logan76]

clean your MAFS make shure the wires are all still in good condition...

[CrimsonQ]

is it throwing any codes? check engine light on ever?

[ScottJackson]

I had my '92 q45 do that... turns out it was the sock on the fuel pump that was clogged with RTV gel where some idiot who owned the car before me tried to seal up the top of the fuel pump to the tank with lots of orange RTV. It of course dropped into the tank, turned to a jelly texture, and clogged the fuel sock.

[blackeagle113089]

sorry! its a 94 q45and the check engine light came on one a few days ago, shut off car and restarted it was gone. the sticking only started today

[maxnix]

Sounds like it could be even your fuel pump. Why don't you measure your fuel line pressure vs. RPM?

You don't mention any maintenance history. Required of posts in Infiniti Online Mechanic, which may be why this post isn't there, as it should be.

[Q45tech]

UNCLEAR are you just saying the tachometer needle sticks and the speed still increases or that the car cannot exeed 55 mph in 2nd gear [~~4000 rpm]?

[blackeagle113089]

i drove it back out today and its going fine now. its moving past 4000 rpm without a problem. im not sure what it was. it could go past 55 but say i was already at 55 in a lower rpm, and decided to pass a car, the rpm would raise to 4000 but would have trouble going past 4k thus the car barely speeding up, as for maintance history, im not sure, i havent checked it with the dealer since i bought it off of someone else

[Q45tech]

At WOT 4,000 rpm is a significant milestone in fuel flow. The injector open cycle [time on milliseconds] maximizes at ~~ 11.0 MS and slowly declines thereafter to 10.5MS @6k and 10 MS at redline.

The cycle time must be corrected for the ramp up to open.......during the first 1.5 MS the fuel flow is less than the 370ccmin roughly HALF what would be expected and very very sensitive to amount of deposit restriction. dirty injectors affect idle and low rpm acceleration the most

Obviously the number of fuel gulps per time period increases as rpm rises 50% at 6k and 62% at redline.

There are other rpm milestones like 2,000 and 2,500 rpm when ecu goes into fail safe due to MAF or CAS weird signals