swapping out injectors - couple of questions

Fatty · Postby **Fatty** » Mon Nov 13, 2006 2:29 pm

ok i got my 460cc's today. i have a couple of questions for you guys. the clips are a different shape so i need to cut the wires and solder the new clips on to the existing wires. does it matter which wire goes to which plug on the clip? i think i remember reading somewhere that it doesn't matter, but i want to be sure before i dive in.
also, looking at it, it looks like all i need to do is undo the 2 bolts on the fuel rail, lift the rail off, and swap the injectors out. is it as simple as that? any pitfalls i need to look out for ?
if there is a write-up on the net somewhere about this stuff, please point me in the right direction. i don't wanna f*ck this up!

Babalouie · Postby **Babalouie** » Mon Nov 13, 2006 3:10 pm

Not 100% sure on the question re the plugs, but when you reinstall the rail, lube the injector o-rings with vaseline or a thick lube like gearbox oil. This is to prevent the o-rings being partially pulled out of their groove when you refit the rail...if that happens fuel will spray out.

Juffa · Postby **Juffa** » Mon Nov 13, 2006 3:43 pm

You will also need to reduce some of the pressure in the fuel system to cut down on the amount of fuel that leaks out with the fule rail removed. I did it by removing the petrol cap. I also had a few rags to capture any fuel spillage, as well as a tray under the car.

Did you get high or low impedance injectors?

J

Fatty · Postby **Fatty** » Mon Nov 13, 2006 3:52 pm

thanks juffa AND babalouie.

any and all tips are appreciated!

these are high impedence injectors from an rx7, a 1988 model from memory.

Babalouie · Postby **Babalouie** » Mon Nov 13, 2006 5:02 pm

Juffa wrote:You will also need to reduce some of the pressure in the fuel system to cut down on the amount of fuel that leaks out with the fule rail removed. I did it by removing the petrol cap. I also had a few rags to capture any fuel spillage, as well as a tray under the car.

Did you get high or low impedance injectors?

J

Oh that's a good point....remove the fuel cap, but also what's also good to do is to unplug the CAS plug. That'll disable the fuel pump. Then crank the engine over to use up the residual fuel in the rails and you're set

Fatty · Postby **Fatty** » Mon Nov 13, 2006 5:16 pm

great!
*edit*
ok the CAS is the thing hanging off the back of the head on the intake side. right?
so that plug...is there a trick to getting it off? i don't wanna break it .

Fatty · Postby **Fatty** » Tue Nov 14, 2006 7:11 pm

ok thanks for the help guys, it worked.
on reflection it was pretty silly to buy injectors with a different shape connector. made the job a lot harder than it needed to be.
but it's done now, that's the most important thing

took me about 25 minutes to get the car tuned nicely wiith the dfa. then took it for a big run of about 170km. the car runs pretty much like it did before, there are probly one or two little things to sort out on my fuel map but i'm 95% there. and get this, my fuel economy has actually improved

(8.8L p/100km before, down to 8.3L p/100km).
so there you go. 460cc injectors running on the stock ecu. this may give a few of the turbo guru's something to think about. coz as far as i know, most people running the stock ecu use smaller injectors then use fuelling tricks like upgrading to a higher pressure walbro pump, using a afpr etc etc. whereas the aftermarket ecu guys usually just fit the bigger injectors.
so this might be another option to think about. just thinking out loud here, i'm no expert but am aware of the small injector+ high pressure, big injector+low pressure comparisons.
anyway this dfa seems a lot better than an safc for example, i don't think that unit has enough resolution for such a big injector upsize. i got it tuned and running sweetly in under half and hour.
pretty happy with that.

oops sorry about the long post guys