MY friend with a 1987 N/A FC wants to know how to tell the difference between which ones are primary and which ones are secondary. They are S5 Rx-7 injectors (if it matters) and they have a red top. Any help?

 

the primaries are under the manifold....

 

Primary injectors are closest to the where the intake enters the engine. The secondaries are back further on the intake stream.

 

Damn I feel dumb! I forgot to mention he just ordered these injectors and wants to put them in, and wasnt to know which one is the primary (not on car) and which is seccondary, or does it even matter?

 

all 4 should be the same injectors and will not matter which one goes where

 

I think he's asking how to tell when they are already off the motor, correct? Just thought I'd add that.

 

welp now thats fixed....yea I don't think it matters

 

it doesnt

all 4 are identical

 

Thanks guys, sorry for the previous miss communication.

 

Ok now he's got one more question. Where do you install the secondaries? Anybody have a pic I can use maybe or a diagram. Sorry if these are noobish questions but I have yet to read on the fuel system.

 

They are located on the fuel rail, on passenger's side, ontop of the UIM.

But the S5 injectors are high impedence, while the S4s are low impedence. The plugs for each are physically different. You cannot use S5 injectors on an S4 harness/ECU, and vice versa.

 

88's are s4's and high impedence

 

White87FC You are partialy correct. Pre 87 1/2 use low imp. While anything made after 87 1/2 does use high imp. I'm not sure if the plugs match on s4 & s5 hi imp though.

 

i am the friend 87 is refering to, and i am a newb...okay i'll take the hit!
what ik dont understand is how do i get to the secondaries? what must i take off (or explode) to make it accessible to make the change to the new ones?
Also blackn/a....how would i check to see if they fiton my s4? all i know is that the new injectors are from a 1989 s5 and was wondering if there is anyway of putting these on my s4 without creating more havoc for myself. if anyone lives in cali maybe you could come check it out and hopefully get my "EVELyn" back on the road where she belongs... thanks guys for all the info, everything is appreciated!
And 87, thanks for the help too....I just found this site today while researching.
thanks again guys,
-Smurf-

 

To get to the secondaries you must take off the intake tubing and the little elbow connected to the throttle body. After that you should have enough room to take the two bolts that connect the Fuel Rail to the UIM (upper intake manifold). After you take the bolts out you'll be able to pull the fuel rail up. Then just gently twist the injectors out of the fuel rail. Some fuel may spill out of the rail.

So, to avoid that take out the pressure in the system. Just unplug the wire harness to the fuel pump and start the car and let it die. This will git rid of any fuel in there, and then unscrew the gas cap a bit. After you put everything back together you'll need to put pressure back into the fuel system. To do this plug everything back up. Then look for a yellow two prong plug by the passenger side shock tower. It will be on the side of the intake tubing. Use some wire to bridge the plug and turn the key to the on position. Only do this for a few seconds to let the fuel pump pump fuel into the system. Then just unplug the wire and start it up.

haha that's a lot of writing but it puts it in a nut shell for ya. Oh and I forgot to add. Be carefull when putting the injectors back in. The o-rings on the top can break easily and will cause a fuel leak for sure. It's probly best to order some o-rings from the dealer before you do it. I just got mine today actually.
Part # 8574-13-253

 

thanks drifter,
that helps ALOT! but at the same time isn't that the location of the primaries? if not what would i have to do to get to them? How far are you away from Magic Mountain in valencia? maybe you can come over and get my 7 running and i will be indebted to you for the rest of my life...lol
thanks again,
-Smurf-

 

Your stock injectors, were they red topped or was it purple? If the stockers are purple, those are low imp and the new red tops will not work on your wiring harness. If they are red also then its just a matter of if the connectors fit. There might be something about that in the FAQ or Archives(<- tons of good stuff there!)

 

I would've given you a link but I'm not allowed ot advertise on the other site. Well now you know my secret. Good luck solving everything.

 

 

Seriously, is the Factory Service Manual infected with herpes or something?

Open the manual, go to the fuel section and look at the overview. Should be obvious.

The Haynes manual also contains this information in a less cluttered way. BOTH manuals are mandatory for working on this car. The Haynes for quick reference, and the FSM for the details.

Injector part numbers and colours are also in the FAQ.

 

Sorry man but I live in Nor-Cali. I used to reside in So-Cali and I know your area decently but that's too much of a drive! In the pictures above they pretty much explain everything for you. The ones I talked about are the secondaries. They are in plain sight. You should be able to see them without taking anything off. The primaries though are a little bit harder because you have to take off the intake manifolds on top. You also risk messing up the gaskets on the manifolds and have to order new ones.

 

Holy ****, you guys are GODS! if all of that doesn't work i don't know what will!
Blackn/a: the stock injectors and the new ones are both red... so i will check on that today.
87: thanks and now i feel alot better knowing that this site is actually helpful!
my5ababy:Holypoop! can you make it anymore clear? well ****, since you have done all that wanna come over and change the injectors yourself???LMAO
aaron cake: I didn't get a FSM with this car and my chiltons manual is a POS and didn't help at all when i read on this subject....but thanks.
adrift: thanks for your help and i understand the distance thing, just thought it wouldn't hurt to ask...lol
Again, thanks to everyone that is helping me put "EVELyn" back on the road.
thanks,
-Smurf-

 

Thanks guys for clearing up the impedence issuue. I knew they changed in mid 87, but it slipped my mind.

 

You can lube the gaskets with vaseline incase you're thinking of taking them off again soon.

No problem.

You can find the FSM online. It's linked in the FAQ. Personally, I have it printed out and put into 2 binders. The training manual is in a separate binder.

 

okay so i found out that i got the wrong injectors....newbie, right?
but was wondering does anyone have any extra 460cc low impedence injectors for an s4? or does anyone know where to get them? also anyone wanna buy these s5's i got?
thanks guys,
-Smurf-