With the upgraded fuel pump recently installed, it was only a matter of time until my lovely Nissan 200SX S15 Silvia Pearl got some higher flowing injectors installed. Tuning my car onto e85 was so close! I just had to install them…
I decided to go with Five O Motorsport 1000cc injectors from the U.S which offer great value and performance from what I’ve read on various forums unlike your backyard garden hose highflow injector variety – and not to mention Jay recommended them (I listen to his advice so he doesn’t get cranky… plus he’s my race engineer).
They are essentially re-manufactured OEM JECS injectors, which puts some of my quality concerns to rest since most aftermarket injectors are JECS anyway.
I was just a little surprised by the fact that I could actually get beefy sidefeed 1000cc injectors for less than $500 delivered considering bigger brands cost much more… call me skeptical (and frugal)!
But you never know until you try it out for yourself so here we go!
Note: It is recommended that you have gasket sealer handy to securely seal the plenum to the throttle body. Also, I replaced the lower intake plenum gasket since I was pulling everything apart as it might have ended up crumbling knowing my luck (Part #14032-65F00 for S15).
Tools Required: Pliers, Philips screwdriver, vice grips, allen key set, ratchet and socket set
Duration: 3-5 hours
Unbolt suspension nuts and remove strut brace if you have one. Remember to bolt up the nuts back by hand on or otherwise you’ll get a surprise (like me) when you jack up your car.
Unclip the four rear white, grey, brown and purple connectors.
Unplug the rear brake booster vacuum hose from the plenum.
Unbolt the two common earth cables from the rear of plenum.
Unbolt the earth cable from the side of the plenum.
Unplug the vacuum and carbon canister hoses from the throttle body.
Loosen the bolts on the throttle cable holder with a spanner and unhinge cable end from throttle body and detach completely.
Unplug the brown TPS connector from the throttle body. Now it’s time to remove the throttle body from the plenum via the four allen key bolts. The bottom ones may be tricky so removing your intercooler cold pipe for better accessibility helps.
Hopefully you have a good quality allen key set as the bolts will be done up really tight. Victory will be yours when you hear that glorious creak and crack.
Unbolt the 2 x 12mm bolts holding the plenum to the side block and also the 2 at the rear.
Remove this vacuum hose from the plenum, this connects to your Fuel Pressure Regulator (FPR).
Unbolt the 5 x 12mm bolts on the plenum itself which hold it to the block – note the length and where they belong.
Detach the plenum from the runners, this will leave the intake runners exposed. Cover them with a cloth so that no debris or dirt can get inside.
Unclip the connectors from your existing injectors.
The screws will be very soft so ensure the Philips screwdriver you use is the exact fit as you don’t want to thread these. If you don’t have any luck with the screwdriver, carefully use vicegrips to spin them out (we had to resort to this too).
Remove the covers and have a cloth handy as you pull out the injectors in case there is fuel spillage.
Wipe around the injector seat to remove dirt and any excess fuel before installing the new ones. Jay blocked up the other ‘injectorless’ holes to prevent any dirt getting in which was probably a good idea.
The Five O Motorsport injectors already had brand new O rings installed on each injector which is handy, but if yours doesn’t just install them on the top and bottom of each injector.
Using some motor oil, lube up the injector seals then insert the new injector into the seat and push firmly in, whereby you should hear a pop indicating it is securely in place. Screw the cover back on and plug in the connector. Repeat for the other 3 injectors.
Now it’s just a matter of reversing the process! Remember to use that new plenum gasket if you ordered one and whatever you do don’t forget the FPR vacuum hose!
Nissan recommend tightening the plenum bolts in this order:
Also remember to whack on some gasket sealant for the throttle body gasket.
Check that there are no hoses or connectors left dangling or any spare bolts/screws lying around.
Now the fun part of rescaling your tune for these new bigger injectors begins!
Definitely nothing too complex or finicky with this install, just a bit of time possibly wasted getting unabiding hoses, bolts and screws out.
Good luck and let us know how you go!