UPDATE:

replaced stocker fuel pump with a walbro today (borrowed from a friend), no change in problem... !

i put the stock fuel pump back in and its still the same. i did realize however that if i stay in the throttle it will push through the hesitation but still stumble a little bit. i just did it a couple times to see what would happen, and it makes it through the wall if i stay in it.

i am extremely confused now

 

theres a fuel pump relay that is supposed to switch ver from 9v to 12 v when the extra fuel is needed for the secondaries or when you get into boost. it may be that your relay isnt working and your stuck in 9v mode. u can bypass this relay and run a continuous 12v to your fuel pump to see if it fixes it. if so the relay is broken.

 

So, if you keep on the throttle, it gets past it and starts accelerating normally?

 

yes. like if i start at 4000rpms in 4th gear i can ease into boost and get past the hesitation and it will boost smoothly.

i STILL think its a lack of fuel

 

It's either fuel or ignition. I would put in a fuel pressure gauge so you can see what's going on. Just get a cheap on and just velcro it or something into the cockpit just for troubleshooting purposes.

 

i ran a wire straight from the battery to the white/redstripe wire on the fuel pump plug... before hooking the wire up, it was at 9v sitting at idle. i went for a drive and the problem persisted and nothing changed.


after removing the wire from the fuel pump straight from the battery, my fuel level gauge is pegged at the bottom... how the hell did this happen?

 

you sure you got the right wire and didnt screw up the sending unit for the fuel level? with the car on key-on or even all the way off the fuel pump shouldv started up when you connected it..did this happen? if not...then who knows

 

<sigh>

you prolly fried the fuel level sending unit. Have no fear... I have one for sale :o

ps: prolly hooked up to the wrong wire or something.

 

to test the fuel pump under 12v you can always just jump the relay in the engine bay...a wire from + battery to output of relay..

 

actually the plug was partly unplugged... lol so the gauge is fixed now.

also, my studdering problem fixed itself

 

haha honestly? so after all this now it's working like normal again? you knwo i've seen relay get stuck and sometimes when you jump them they start working again...i remember doin a fuel pump on a p.o.s. tiburon and we thought the relay was fried but we jumped the relay, and after that it worked fine... glad to hear the problem is solved though

 

Glad to hear yours is better.

I'm still fighting with mine. I tried putting the stock secondaries back in mine on the stock computer... same problem. It jumps REALLY bad at like 2k, and can get through it with lots of babying. it also can't take more than 20% throttle inputs.... i'm inclined to try another wiring harness at this point I guess

 

this thread is extremely old, but i need to bump it.

this hesitation problem would come and go, which really baffled me. i eventually got fed up enough to get rid of the damn stock ECU and get a haltech, since i have experience with them.

i ended up buying a haltech e8 and ran it for about 6 months, but ended up selling it when i was in dire need of some money. i decided to go back to the stock ecu, but made sure to get a different wiring harness, coils, igniter, MAP sensor, but still the original ECU.
so even with a new harness, coils, igniter, MAP sensor, the problem persists! i'm now at the point of assuming it's the stock ECU that has some sort of internal problem. i'm going to swap it out in a few days and see if that fixes it.

 

I own a 2000 RX7........and I am having the same exact trouble that you were reporting on.

I am in the midst of troubleshooting and searching for a solution.

I had the Fuel Pump Relay off the car and I am ordering a new one.

My problem comes and goes also.......but 90% of the time the car stonewalls at 0 psi

Did you ever fix your problem? If yes.....how?

 

bump!! i know this is an old thread but i have the same problem!!! need help!1

 

I had a similar problem. I fixed mine by cleaning the contacts that the fuel pump relay plugs into. I suppose you could just jump the relay and provide a constant 12V but you'd need to look at the wiring diagram to see which pins went where.