i have a 90 NA GTU and my injectors are killing my gas mileage and idle. i want to send them out to rc engineering for cleaning but i am the worst when it comes to working on my car. please give me advice on how to even begin. thank you.

 

give me 30$ and ill come over there and do the whole thing for you. (assuming your in the oc area)

 

Get a Hayne's manual and download the FSM (factory service manual).

You have 4 injectors. Two are on your upper intake manifold, and two are you on your engine itself.

 

DON'T get someone to do this for you (sorry rs_1101). You need to learn how to do stuff on your own when owning a 7 or you're gonna be SOL.

Search for how to remove the UIM (upper intake manifold). Once that's off you'll see the 2 injectors on the engine and it'll be apparent how to get them off.

GL!

 

its really easy. take bolts off. when your done, put them back on. i can get it off in 5 minutes. back on in 10.

 

Ignore that he just said. It's not THAT easy. If you just "take off bolts" you'll end up breaking something.

 

he is right to a point. ill give you a quick rundown, but i suggest going to iluvmyrx7.com and looking at the schematics to see what mazda has to say about it.

take off the plastic intake tube. youll need a + screwdriver and a 12mm socket.
unhook throttle cables from back of tb. use tape to hold nuts in place so you dont have to adjust later. the CC cable will have a little bracket you have to remove as well. at this point you can clearly see your upper fuel rail. disconnect fuel hoses (may want to replace those while your at it). then remove the 12mm bolts holding it on. now unhook the coolant line in back of the TB, and the other one on the BAC. you can remove the entire UIM and TB assembly as one peice. depending on how strong/manly you are you may need a friend to help.
dont forget to use paper towels to plug all of these holes to prevent debris falling into your motor. when removing vacuum lines, use something to mark what they connect to. you may want to buy about 4 feet of vacuum hose to replace while your down there too. also make sure to note where bolts go, with labels or bags or something. you will forget.
now remove the bolts holding the uim on, where it connects to LIM. careful of the big one, i can imagine it could break. most of these old mazda bolts can be easily overtorqued. you shouldnt have to put them on very tight.
now go to the drivers side and undo the support bolts. to get the one further back, you may need a 10mm socket to remove the secondary BAC and the large vacuum hardline on back of the TB, makes the whole thing much easier.
when your about to get the third support bolt off (or are there 2?) youll need a friend to hold the uim up. carefully lift it out of the car, and your UIM is off.

i just wrote all this before i remembered you have an s5, but it should be similar. this was described for a series 4 na. its pretty easy, in the scheme of things, but if your a beginning mechanic, make sure to take the time to plan it out. when you actually do it, the first time, take your time. go slowly. check all connections when you get it back together. your not going for a speed record yet.. let that wait till youve done it 6 or 7 times (like me) i have to admit. the only reason im good at it now, is because the first 4 times i always forgot to hook something back up when i put the uim back on, so i had to do it over and over again.

you will need RTV, vacuum hose(optional) and an emergency ride to the hardware store in case you break something.

 

also start the car and let it run then kill it by taking out egi fuse. this will depresurize the lines so not as much fuel will leak out.

 

Or better yet, just unhook the fuel pump wire.

 

I'd say undo the fuel pump wires and let the car sit over night to really relieve the pressure.

 

good thread!

 

I always do this and there is still a lot of fuel that comes out. Just have a rag handy when you pull the injector out of the rail.

 

alittle gas never hurt anyone. unless that someone was smoking..

 

The Haynes says to open your gas cap, unplug the fuel pump (on the driver rear shock tower under the carpet/panel), then start the car and wait for it to die on its own. That relieves the fuel pressure. There's no need to let it sit over night, and it won't harm the engine to let it run out of gas. Just be sure to prime the system before trying to start it after you're finished, and check for leaks.

 

Don't boost in 4th with the fuel pump unplugged.

 

contary to popular belief. a cigerret won't start a fire it it gets near fuel. cigerret heat only reaches in the average mid 600 degree it takes at least 1000 degrees to start something like that. "but if you blow on the cigerrett pusshing oxygent and fuel togeather you get a catalistic effect." i've tried it and burned the hair on my hand.

Oxygent if burnt can create 6000 degrees of heat. (that can melt steel) a regular cigerret only burns 650 ish degrees while it smokin. blow more oxygent you get the (TURBO) effect. if fuel is supplied then we get our combustion.

one might say "if a spark can start a fire why can't a ciggeret?" well a spark has tempitures at well within 1500 degrees but it's only for a short time. a ciggeret can Start a fire. but it needs a catalist effect.

 

So what temperature do gas FUMES ignite at?

 

fumes isnt issue when it comes to igniting. At a gas station there are fumes everywhere. yet i can tell you that lighting a lighter in the air won't cause the whole place to ignite the ball of fire.

it's really determined bye the amount of gasoline fumes within an area. although our noses can sense the fumes in the air. they are most deffinatly not compact in a level where a lighter in the air can ignite it.

fumes itself won't trigger itself to a catalist effect due to the Nitrogent content in our atmosphere. not only that Gasoline requires a Catalist (spark or flame above 1000 degres). but requires a certain amount of oxygent nearby in present as it's cumbustion source.

the light off a cigerrett is not a flame it's heat! grab a 1 dollar bill and point a ciggeret by it. it shoud burn right through the dollar bill. that is because oxygent is nearby in the other side pulling it accross the dollar bill casing the dollar bill to burn through. oxygent is being pulled through the dollar and burning it in the proccess. should you put dollar on your hand and attmept to burn through the dollar. the dollar will not recieve any substansal burn mark. and the nerves of your hand will screem about it.

our atmospehere is 60% nitrogen. 20% oxygent and like 5% carbon dioxide and the rest is everything else. nitrogen it'self is kinda a plugger for things that want to explode. it virtually slows down everything. (Kinda the same thing when people use Nitrious in their cars) you try to run the a car out of pure oxygent and for sure you'll melt your motor. yet nitrogen acts as a surprssor to slow down the process. that's why fumes don't light up when you bring a 650 degree cigerret nearby fumes.

Alot of times people say, "Dude im low on gas my car is running off fumes" That's true! alot of times car's will only run on fumes. due to the fact that a given amount of fumes is given a certain amount of oxygent, and a certain amount of heat and spark is present. but also a GREAT AMOUNT of compression is added. Nitrogen or not a compressed area, oxygent compressed, and a high degree spark is added. Will cause an explosion.

on the other hand. 650 degrees is kinda stupid to be playing around an extreamly cumbustable liquid. it only takes about 1200 degrees-ish to light up fumes or gasoline. 650 is half way there. that's why it's always recomended that you don't smoke when working with gasoline. and don't even think about lighting up a lighter. those things start at a basic heat of 2000 degrees

 

Wow, he really appears to know what he's talking about.

 

Damn mr wizard up in the house!

Anyway.

Don't go to RC. Thery rape you for $$$.

www.cruzinperformance.com has done 6 injecotrs for me and they all work fine right now.
4 550's and 2 460's.

I believe he charges 11 per injector which is a great price.

 

This is a GREAT thread! I love it!! Cigarettes!! Injectors!!! FUEL!!! WOOT!!!

 

You kidding? I learned everything off Bill Nye the Science Guy!~