I put in a new Bosch O2 sensor today and hopefully that helps, I won't know until tomorrow when I drive it. MY 1990 RX-7 is running so incredibly rich, I am convinced my computer is telling the car that it is in the South Pole at all times, and to dump as much fuel on the fire as possible. I put in a new coolant temp sensor, but still now change. What other systems ought I to be looking at? Could the BAC valve cause a rich condition by itself? I suspect the BAC valve might be gone or going because it fails the heater fan test. That is to say, when I turn my heater/cooling fan on (without A/C button on), my idle drops a few hundred RPM and does not recover ever. According to what I have read, this implicates the BAC valve. Is this correct?

 

You say you replaced the coolant temp sensor. Would this be the one located on the backside of the water pump? Is so, it should read less than 2 volts when warm and closer to .5 volts fully warmed up otherwise it reads 2 to 3 volts when cold ( specs for S4, S5 might be different). Double check the S5 FSM and you can take the most accurate readings at the ECU.

 

Leaking fuel injectors? Vacuum leak? Low engine compression? BAC has nothing to do with fuel mixture.

You have an S5. Pull the codes and make sure nothing is obviously faulty.

 

I say clean the injectors. I had one of my primaries AND secondarys stuck open and you could'n t even stand behind it. Eyes oh my eyes, I'm blind i'M blind.

 

My car is doing the same thing -- it's so rich I'd say half of what I am smelling is unspent petrol coming right out of the tail pipe and boy does it BURN!

So you just sent the injectors off to be cleaned and that did it? Or did you actually buy new injectors? Who sells new injectors for an S5 NA and how much are they?

Who do you folks recommend for cleaning them and how much does it cost? I have already run Redline SL-1 cleaner through but I don't think that will undo a stuck open injector???

 

RC Engineering....

 

thanks.

 

thanks , ha . you wont be saying that after you see the price. look up witchhunter on google , i think they charge 16 per injector for service and flow comparison plus shipping. injectors dont blow (typically) they just get dirty and either stay open or leak, if you took one of yours out youl notice the rings are nearly solid ,not good for a gasket.

 

$70 is a bit steep I would say but if it works and clears up the rich condition it would pay for itself by fuel saved over the course of a few months.

So you are saying the injector gaskets harden and no longer allow a good seal? Do they ship them back with new rings?

 

no its not just that there is a whole lot more than just gaskets on the outside that cause leaking , and the leak these might cause would be external residue. if you think 70 is steep go on ebay look up rc engineering injectors rated 550cc or 460cc (you never mentioned model) high imp for your s5 . or go to napa and see there 200 + a piece price. and 70 isnt your total its around 100 by the time you get them back.

dont forget brand new everything and you will still be in numbers between 12.1 and 14.1 , which is rich by any standards. its the wankel . but when you know it is excessive its time to look at a 60k tuneup

 

I meant RC Engineering, he can get them flowed and cleaned from them... Not new injectors... But yes, they better well should come with new o-rings and grommets or I would be mad!

 

Witchhunter is in bothel. call them, find out when you can drop them off. They do great work.

http://www.witchhunter.com/

 

Invaluable info. thanks AUGie. Calling them tomorrow. What else do they do?

 

everything for injectors , they are an injector servicing company.

 

Yup thats what they do.

 

I'm new to owning my RX-7, but I will vouch for WitchHunter.com as being outstanding. I had my Jetta injectors serviced and holy crap--I couldn't believe how huge of a difference having one slightly underperforming injector could affect the car. It wasn't horrible by any means, but it wasn't in tandem with the others and after the full servicing the car ran MUCH more smoothly. I'm thinking I'll send off my RX-7 injectors soon, just to know how they're doing.

I had another, local shop perform cleaning on two other cars' injectors and I mentioned how much I liked WitchHunter's process and the data and they knew of them and assured me I would get everything I wanted. They're Corvette specialists and have their own injector servicing machines and ultrasonic cleaning baths. Nope, the injectors didn't come back looking brand new like they did from WitchHunter, and even though one set had about 140k very rough miles on them, I didn't feel any difference whatsoever. They costed more, but I wanted the convenience of a one day turn around without shipping latency and I literally paid for what I got--faster turn around and nothing more than some new pintle caps, o-rings, and a moderate bath, it seemed.

WitchHunter is tops and I get the feeling he over-engineers his work, which I greatly appreciate because the results are nothing short of outstanding. You get back your old parts and can see how nasty the filter baskets are, which can be quite horrifying depending on your standards.