i have a 87 rx7 se that had a 13bt put in it. my buddy couldnt ever get it to run right so i bought it. the problem i am having is its getting way to much fuel. it floods out rapidly. ill spin the engine backwards and there will be so much gas coming out of the spark plug holes. it has a wahlbro 255 in it. and a aeromotive fuel pressure regulator. it was set at 45 so i adjusted it down to 40 still same problem. then i went to 30 and still does it. i tried different injectors too. right now i have 720s in it. i even tried stock na injectors and still the same. any ideas? its just its just dumping fuel in the housings.

 

What kind of fuel controller is it using?

 

Improper injector sizes?
Leaking Injectors?
Stuck open AFM?
Improper ECU type?

could be 1 or many things working against it.

Does it dump fuel into the engine when the key is turned into the ON position? This will prime the fuel pump and allows you to find any injector leaking without the engine running.

 

unplug your fuel pump so you dont keep pumping fuel out your plug holes...

then make sure your ignition system is disabled... don't want any sparks when working around gas fumes

then check to see if there is power going to the injectors when the ignition is on

if you have power runing to your injectors then you have an electrical issue


if you don't then you probably have a bad injector sticking open

 

the ecu is a n333. the top injectors i have on right this moment are the denso 720's. they are the bright orange or dark yellow ish. the bottom injectors are denso 1350's or 1370s cant remember exactly. it has a stock turbo with the biggest street port u can get. kevin landers built the engine for my buddy.i have tried 3 different sets of injectors. ill try a different afm. i have one laying around. is that the right ecu? its all s4 electronics

 

By bottom you mean the primaries, the ones going directly into the block right? If so, those are waaaaaay too big. put the 720s in the primary locations and the 13xxs in the secondary location. It will still run rich, but not as rich.

 

ok thanks man. but i took my volt meter to the injector wires and and i had 11 volts to the injectors key on engine off. is that bad? does that mean they are open the whole time?

 

well the part number is 1350 or 1370. not the size of injector. i think they are like 550's or whatever size the stock ones are for the na's

 

You either need four 460cc injectors or a fuel computer (S-AFC, RTek, standalone EMS, etc.). The stock computer is not able to run the engine properly with the wrong injectors, as you have seen.

See this link for the proper 460cc injectors.
http://www.rotaryresurrection.com/2n...ctor_info.html

 

i tried all 460cc injectors and still did it. is the 11 volts with key on engine off bad to the injectors?

 

The injectors have power any time the key is put to ON.

The ECU pulses a ground to the injectors to make them work.

Turning the key to ON does NOT make the fuel pump work for even a nanno second.

And with the amount of fuel you flushed out, I'd wager it's going to be hard to start even if everything was perfect, because you/they/he has washed away all the lubricant from the oil control rings etc and the compression is going to be soooooooooooo low after have done that.

So you might at sometime, squirt some motor oil into the chambers and rotate the engine to get more lubricant around the seals.

 

Either i am weird, or that doesn't sound right at all. Fuel pumps should prime and allow for positive pressure in the fuel lines when Key is ON position and Ignition OFF. During a diagnosis this is called Static Fuel Pressure Test. Does the rx7 not follow this rule, and if it does not.. does this mean that priming only occurs during crank? I know your smart Hailers, but that doesnt sound right. Confirm it please.

 

i got it all fixed. i put motor oil in the housing and put a fuel cut off and didnt what it said on rotary resurrection. fires up every time no problem now. runs amazing.

 

The fuel pump is controlled by the Circuit Opening Relay.

The Circuit Opening Relay has two coils that can pull it in.

I attached a jpg showing one coil in Blue and one coil in Yellow.

The Blue coil has a ground on it all the time. It gets power when the Starter Circuit gets power put on it. You put power on it by HOLDING the key to Start.

The Yellow coil has batt power on it if the key is ON or better. That coil will pull in only if you put a ground on it. You put a ground on it by the Vane in the AFM moving aft by at least a 1/8" give or take. The mico switch in the AFM, when moved aft will *make* and put a gnd on the Yellow coil. The other way to put a gnd on that coil is to jumper the yellow, two socket Fuel Pump Check connector near the afm.

I attach a jpg and colored the two coils Blue and Yellow.

A fully depressurized fuel rail will be pressurized in less than two seconds when the key is put to Start.

The wiring came out of a 86-87 FSM and is for a non turbo. Turbo works just the same as far as the Circuit Opening Relay.

EDIT: And the AFM has nothing to do with fuel delivery duing START. Only after the rpms are over 500rpm does the AFM play a roll.

Stock fuel pressure in the rail, during Start, is something like 37-39 psi.

 

Ahh makes sense! Thanks Hailers...yet again...lol

 

he is running a n333 which is a turbo ecu

550s would be the proper injectors not 460s... Correct?

 

yea i think im gonna switch back to the 550s tomorrow. i dont want to be too lean.

 

will it hurt to run the 460's? will it lean out? im running stock boost right now. or should i put the 550's in?it pulls hard and good all the way to 8000 rpms. no cut outs or nothing. is it normal for it to seem like its missing when u hold the gas in one spot. say like 2500 rpms.it just sounds like it has a miss. but the revs are good. idles somewhat ok.

 

yeah put the 550s back in,

if it is too rich, decrease the fuel pressure a little

its better to be a little rich than too lean

 

i have a aeromotive regulator on it right now set at 35 vaccum on.can i just bump the pressure or do i NEED to switch them out? i have 700's i can put in. should i put them as primaries or seconddaries?i would say secondaries cause thats when the turbo is spooled up the most right?

 

secondaries are usually the bigger ones on modified engines

I don't think the 700s are going to do you much good unless you have something to control the fuel with.

I ran a walbro 255 on a streetported TII engine with stock 550s and a stock regulator up to 12psi this summer and my afrs were good all the time. I wouldn't mess with the 460s if you have the right injectors sitting right in front of you.

If you are dead set on running the 460s for some reason you better have at least a wideband to keep an eye on AFRs.

 

im not dead set on it. i just didnt know. thanks guys for all the help.