issues
 

so i just bought a TII rx7 with a bad engine swapped a new one in got it running it seems to be timed right but it has upgraded fuel injectors and fuel pump thats it. it seems to be running a little rough until the boost kicks in. it almost seems like its misfiring or seems to chug a little when im running it at low rpms. its runs really well when the boost kicks in like a said. can anyone help me with my problem? thanks...

do you have anyway to control the fuel? what size are the injectors? and what flow is the fuel pump.

i think your prolly just running too rich. you need to get an safc or some kind of fuel management and wideband to tune.

lol help me out here i'm kinda new to this whats an safc and all that?

im running 720 and 550 injectors and i beleive the fuel pump is 255

http://www.alamomotorsports.com/apexi/safc.html

Here is a link to a site that describes how it works

thanks it helped me out alot!!!!

I'm curious, do you have a wideband? I would bet that you're running rich since the 255 is dumping fuel in probably at a higher pressure than stock. If the 550's are in your primary location you're getting too much fuel in. If the 720's are in the secondary you only compound the problem when you get in the upper rev range. If it's reversed, you have way too much fuel there. And it only slightly begins to tapper out when you open up the secondaries. In either case it doesn't sound like you have a way to control the fuel for the upgraded injectors.

yes i dont believe there is anything to control the fuel for the upgraded injectors. it only runs bad at low rpm once it hit high rpms it seems to be just fine. i'm not really sure what to do so if theres any advice and pointers on how to do something to fix the problem that would be great.

can anyone else help? should i go with a fuel pressure regulator? and safc?

Seriously...
You sound like you're in over your head.
Find competent tuner / shop that will take care of this for you.
This is the fastest and quickest solution to fix your problem right now.

Long, messy explanation...
The stock Turbo II comes with 4 x 550 fuel injectors.
If you swap a pair of them with larger 720's, how does the stock ECU know you've done this?
You're lucky the car runs at all.
It's not surprising it's running like crap.

You do not mention where the 720's are mounted.
If the 720's are in the primary positions, the car is going to run like crap.
Verify that the 720's are in the secondary positions - this should allow you to drive pretty well under 4kRPM.
It sounds like the 720's are in the primary positions.

To the dumbf*ck PO that f*cked up this car...
It's sad that people mess with these cars and dump them like this.
People, don't just buy abandoned projects like this without going for a test drive - why would you buy something that doesn't drive right?
Luckily this is your problem as described above, but on the extreme end, the motor could be no good!


-Ted