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-   -   Injectors vs. Intake Manifold (https://www.miataturbo.net/diy-turbo-discussion-14/injectors-vs-intake-manifold-56473/)

skidude 03-22-2011 06:20 PM

Injectors vs. Intake Manifold
 
What's the easiest way to replace the injectors in an '02? I just went to do it, expecting it to be easy like my '94, but it looks like the intake manifold is in the way. Can I just take the top part off the manifold and get to them, or is there more to it?

Also, the old injectors are thin and pointy, the new ones are regular shaped. Not sure how I didn't notice it before, but are my new ones going to fit alright?

fooger03 03-22-2011 06:31 PM

remove upper intake manifold (which involves removing TB and associated bracing), then remove 3 bolts in fuel rail. The fuel rail bolts go through 3 plastic heat insulators before bolting into the head. DON'T LOSE THE INSULATORS or you will have to sell your soul to the devil to find them. The injectors will come away from the head still attached to the fuel rail.

skidude 03-22-2011 10:37 PM

Thanks! And I assume the new injectors, as fat as they are, will fit just fine?

Also, should I clean anything while I have the top of the intake off, or leave it it's probably fine?

shlammed 03-22-2011 11:12 PM

Take off the intake and leave the throttle body on. Or you will need a new gasket.

thirdgen 03-23-2011 12:34 AM

I have done this over 6 times.
I do it like this:
Remove the inlet piping going to the throttle body. Unplug your TPS, and IAC valve. Remove all bolts on the upper intake, I think there's 6? The ground source near the throttle body has a funny little bent tab looking bracket with 2 bolts in it, take it off. Under the throttle body there is a tab with 2 bolts in it that I think bolt to the lower intake? I can't remember, it's late, but those 2 bolts need to come out. The actuator for the VICS, you can leave connected. I just lift my intake up off the dowel pins and kinda pull it outta the way.
Towards the firewall side of the intake manifold, there is a round looking thing with 4 phillips head screws on it. Take out the screws and lift that thing out. Next is the fuel rail. 3 bolts I believe hold it down. Take them out, and lift the rail, but watch, cause under the rail is little spacers and if they fall out, they tend to dissappear quick. They are camoflage with your frame, meaning when they fall, that's where they usually land and they become invisible. Anyway, once you lift up the rail, pull 1 injector at a time, and you can sort of manuever them around to get the plug off of em. Make sure you lube up your new o-rings with vaseline or something before putting them in. I put all 4 injectors into the rail first, then I carefully seat them in the bosses on the intake. The fuel rail should easily go down against the black spacers. If it doesn't you need to make sure your injectors are going in right.
I have this down to a science. I can do this job start to finish in less than 1/2 an hour. The first time took me a while. Just have patience, put everything back exactly as you took it off, don't try to force anything and you'll do fine.

fooger03 03-23-2011 07:17 AM

remove your fuel filler cap and drain the pressure from your fuel lines first - in case it's been awhile and you've forgotten since doing them on your '94

skidude 03-23-2011 08:15 AM

Thanks for the reminder on th pressure, I had actually forgotten.

Faeflora 03-23-2011 09:29 AM

Yah don't drop shit down your intake manifold.

DON'T LOSE THE STUPID INJECTOR RETAINERS. Your shit will LEAK without them.

DO NOT OVER TIGHTEN THE FUEL RAIL TO THE HEAD. SNUG IS OK.

Once you have everything fuel related on, put your key to power on. The fuel pump will prime. LOOK FOR LEAKS. IF NO LEAKS THEN BOLT YOUR INTAKE PLENUMBACK ON AND PLUG YOUR SHIT UP.

chpmnsws6 03-23-2011 09:34 AM

With the car running, unplug the fuel pump fuse. This will drain the pressure out of the rail. You will still have a full rail, but not a full pressurized rail.

dgmorr 03-23-2011 10:09 AM

You can do it with the entire manifold on. I did it without removing anything. Expect cut hands if doing this.

Braineack 03-23-2011 10:12 AM


Originally Posted by Faeflora (Post 705197)
Yah don't drop shit down your intake manifold.

DON'T LOSE THE STUPID INJECTOR RETAINERS. Your shit will LEAK without them.

DO NOT OVER TIGHTEN THE FUEL RAIL TO THE HEAD. SNUG IS OK.

Once you have everything fuel related on, put your key to power on. The fuel pump will prime. LOOK FOR LEAKS. IF NO LEAKS THEN BOLT YOUR INTAKE PLENUMBACK ON AND PLUG YOUR SHIT UP.


Something tells me someone had a bad experience or two.

dgmorr 03-23-2011 10:16 AM


Originally Posted by Braineack (Post 705213)
Something tells me someone had a bad experience or two.

It wasn't in his thread. I refuse to believe anyone person can have anymore fail on one car. I think he just has volume control issues or likes yelling.

flounder 03-23-2011 08:39 PM


Originally Posted by dgmorr (Post 705212)
You can do it with the entire manifold on. I did it without removing anything. Expect cut hands if doing this.

Wow, kudos if true.:bowdown: It's so easy to pull the upper though, I'd still go that route.

Faeflora 03-23-2011 08:41 PM


Originally Posted by dgmorr (Post 705212)
You can do it with the entire manifold on. I did it without removing anything. Expect cut hands if doing this.

No, you can't. First of all the harness is in the way.

Secondly please explain how you access the fuel rail bolts.

Third there is nowhere for the injectors to go.

Fourth the spacers will disappear.

Faeflora 03-23-2011 08:54 PM


Originally Posted by shlammed (Post 705111)
Take off the intake and leave the throttle body on. Or you will need a new gasket.

Lies. You will not need a new gasket if you take the throttle body off.

Also, here's a nifty time saving trick if you're too much of a pussy to remove your throttle body:

Remove the throttle body bolts and nuts. Leave the intake piping coupler on, attached to the throttle body. YANK ON THE FUCKING INTAKE PIPING LIKE YOU'RE MILKING A BULL ELEPHANT. eventually the thing will come off and you will have saved a whopping 10 minutes.

skidude 03-23-2011 10:40 PM

I did it. I took the throttle body off and didn't ruin the gasket, and I took the top of the intake off and didn't ruin that gasket, and I didn't lose any spacers, and the new injectors fit and megasquirt runs them just fine (a little lean, but I'll tune that out later). Overall a pretty easy job, though a little more time consuming than it was on the '94.


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