RX7 Rotary Rocket

iTrader: (1)

Here's my problem, I changed my fuel pump for a used Denso Supra TT and since then I have to put the gaz pedal to the metal to start the car. I know the pump is bigger and has a bigger flow but what could be the cause ?

- Defective fuel pump ?
- Stock injectors ?
- Ignition (spark plugs) ?
- Fuel pressure regulator ?

BTW is it always good to put the key at "accessories" for a couple of seconds before starting the car to let the fuel pump send an amount of fuel ?

Thanks guys !

amp

iTrader: (50)

leave the key to on for a bit to prime the system...

RX7 Rotary Rocket

iTrader: (1)

Even if I do that the car will crank over but nothing happens it's like there's not enough fuel to start the engine. However, if I push the gaz pedal while cranking the engine would start.

I've never pushed the gaz pedal with stock fuel pump so I want to know why I have to do this now after simply changing the fuel pump...

Jason

iTrader: (5)

You need to check the install. I have seen this happen before and it was the pump not sealing to the stock assembly.

gotparts?

old post, yes i know, but i am having the same problem. car was runnin fine but then installed the pump and same crap is happening. also when i try to get on it it, it starts to detonate real bad. any other ideas?

VegasFD

http://www.rx7.org/Robinette/release_fuel.htm

Read the part on how to prime the fuel system.

gotparts?

will this help with my detonation problem? i didnt have detonatnion til i installed the pump.

VegasFD

How are you diagnosing it has detonation? It would be hard to detonate on startup.

gotparts?

nah not on start up. car starts up fine, just gotta give it gas but when i get on the road itll start detonating when i get on it. it didnt happen til after the fuel pump install

Mahjik

iTrader: (1)

How do you know its 'detonation'?

gotparts?

off of the sound comin from the exhaust. sounds like fireworks coming out of the exhaust. like i stated before, car was runnin great before the install. imma take everything apart again and double check everything. just wanting to know if there is a simple fix maybe? before i take it all apart?

Rex7-93

This is for gotparts, you said when you step on the gas the exhaust starts backfiring and sounds like fireworks. My car was doing this for a while, and I read a post that is you disconnect the neg. batt. terminal and step on the brake pedal for 30 seconds and it will reset the fuel system, so i tried it and my car didnt do the bucking firework like exhaust anymore. it drove fine. When you step on the gas does it hesitate bad too. If you have a tuned ECU dont do this as it will reset the ECU also. Give it a try.

gotparts?

ill try it out bud. i have the apexi pfc running off the base mod map that came with it. ill try it out. any other ideas?

Rex7-93

Im not sure if doing this will mess with the base map on the power FC, i had mine tuned a bit so i never disconnected the battery with the Power FC. and thats all that i can think of. If not that, it must be the fuel pump. Good Luck.

gotparts?

i really appreciate it man. ill check it out now. ill keep u posted!

gotparts?

argh!!!! still does the same thing. me and my father just took it all apart and is doing the same thing still. hard to start. fire cracker sound coming out the tail pipe. anybody?

RX7 Rotary Rocket

iTrader: (1)

I'm the one that started this thread and in my case it was faulty fuel pump so I suggest you to try another one and check if all the o-rings are sealed correctly to the assembly.

Mahjik

iTrader: (1)

Get a fuel pressure gauge (which you should have if you are upgrading your fuel pump) and see what your pressure is with the new fuel pump.

gotparts?

alright bud thanks man. crap. it goes spacer then oring on top then the plastic clip right?

gotparts?

was your car detonating when u got on it?

DamonB

If the car is also falling on its face while there is a firecracker sound coming from the exhaust it's not detonation, you're not sustaining fuel pressure. The most likely reason being your pump was installed incorrectly and is leaking internally inside the tank, or the pump itself is bad. Check the fuel pressure.

gotparts?

right on the dot! i just took the pump back apart and saw that the oring was not sitting correctly. re did everything, put it back together and started right up. took it on a spin and runs perfect!!! thanks all for the help and suggestions!