The symptoms are as follows:

Car: 1989 RX7 Turbo. Stock 550/550 Injectors. Walbro Fuel Pump. 10psi w/ SAFC corrections using Innovate LM-1.

November 2007: 19 mpg. Never flooded.

May 2008: 13 mpg, floods if sits longer than a day. Starts up a little slower. Random miss/rpm drop when idling, cruising, or under load. It is erratic, prominent, but it is not methodic like when a TPS is out of adjustment. My wideband says it shows up as a lean spike (either due to lack of fuel or unburnt fuel). Above 5000 rpm I am actually in the NEGATIVE for fuel adjustment because it runs a 10.0 AFR at 5-6psi. Oh! And when it happens I get a check engine light. But if I drive the car and it doesn't happen I get no light. When I run codes I get upwards of 20 codes so I don't know what good that is...

So far I've gotten the guess of: Leaking injectors.

I plan on going to larger primary/secondaries in preperation for a hybrid turbo. Is there a way to tell if it's the primaries or the secondaries that are leaking? Or should I just replace all 4? Also, are they leaking, stuck open, stuck closed? Is this safe to drive on for another week or two? What brand of injectors do you all recommend?

Is it even the injectors? Or could it be even more than that?
Thank you for all of your input.

 

I'd guess leaking injectors as well. If you knew which injector(s) were leaking you could replace just the one, but since you probably don't then replace all 4. They should be relatively cheap and easy to find on the forum or ebay in working used condition. Or send them off to get cleaned.

 

Well I plan on upgrading so I might as well get 4 brand new bigger ones. I was wondering if it was possible to just buy 2 and swap 2 good ones on the primary rail.

 

.

 

Does this sound like the primary or secondary injectors? Is it possible to distinguish this?

Also, what are people getting for gas mileage with 4x 750cc?

 

The haynes manual lists primary injectors as reason #10 for a bad idle. But it says clogged. I think mine might be stuck open? Can somebody point me in the direction of an injector thread somewhere?

 

Our cars cut fuel on decel right? So if this problem persists during decel it shouldn't be fuel related than right? Please somebody help...

 

Secondaries kick in at 3800 PM.. so you tell us.

Yah its possible if the SAFC supports that (i dont know).

On S4's they do, dunno about S5's. Even if they do... if you have a leaky injector it wont be a good diagnosis.

Clean or replace your injectors. http://www.witchhunter.com/

 

I'm going to get 4 750cc from RC but my supplier is having troubles finding his sources so I'm trying to find different things to try out while I'm waiting for them.

 

make sure you buy the injectors from rc my brother bought some off ebay and they were junk ended up costing him 450 bucks

i didnt see in your thread but have you checked the compression on the motor yet

 

is it possible to actually see what the code says?

 

Sometimes it comes on, sometimes it doesn't.

Sometimes this happens when I drive, sometimes it doesn't.

Everytime I run trouble codes I get like 20+ codes, they are never any help.

 

No I have not checked compression. Is this really a matter of blown or not?

 

I used to have a walbro w/ stock injectors, the car used to smoke on startup and start slow. I switched to an FD pump and the car no long smokes, starts quicker and gets better mpg.

I think the walbro raises fuel pressure too much for marginal stock injectors, getting them cleaned and flowtested will probably help.

 

Still sounds like what my car was doing with bad injectors. Forget the compression test. Why does everyone say that.

 

It starts up fast, but takes a couple of turns. Than immediately dies.
Than it starts up fast, takes less turns, and stays running.
(I usually peg the gas just once to avoid this and it will stay running)

Than it will idle a ROCK SOLID 800 rpm.

After it is fully warmed up, I drove it about 5 miles and parked in my house. Not a problem.

So I decided to take it to an exit ramp and do a 5k launch. Drives great, I merge onto the highway at 65 mph and cruise at 75 mph for an exit, turn around, and repeat.

Get home, park it, nothing is wrong.

What the hell?

Imloggedin, I'm definitely getting bigger and new injectors, thanks for the reply.
Sharingan, thanks for the reply, I'll see what bigger injectors do in conjunction with a bigger pump.

Although I know I have a blown coolant seal (about a glass of water a day needs to be added and it smells heavily like antifreeze near the tailpipe) I do not believe it is blown. It pulls some shitty vacuum (14 mmhg at idle), but atleast the idle doesn't bounce all over the place and it starts up 2-3 turns everytime! No clouds of smoke or anything.

I think I'd like to get it checked just so I know where it's at, but I think this motor has a couple months left in it.

 

Hell my ported motor at 1200rpm idle only pulls 12mmhg at idle. I have to keep the gas down for a bit till it warms up. Only about a minute or two.