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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
Trying to get this to post...
I've forgotten the best format to do multiple replies in one post so...

Originally Posted by bpu699 View Post
Really nice description . Thanks for the detailed response.

"So falure of the frequency valve CAN cause a lean or rich condition based on what you just posted. That would make sense, as it can effect control pressures."

>The lambda frequency valve is in a completely seperate fuel flow circuit frm the CPR and has nothing to do with it.

"So how does he check the frequency valve for function? Is the fact that its buzzing mean that its working?"

>It's an inline fuel injector returning fuel from the lower chamber or lower half og the fuel head to the gas tank.

"Sounds like removing it would lower control pressures, lower the amount of fuel being returned to the tank, and increase fuel flow to the injectors."

>The lambda valve has nothing to do with the hydraulic control pressure level on the top side of the control plunger. Hydraulic control pressure is being regulated up or down by the CPR/WUR returning some of that fuel to the tank.
Fuel flow to the different parts of the bosch k jetronic system is seperated by fuel flow orifices leading to these seperate systems.
fuel pressure in these seperate systems is regulated by returning some of it to the gas tank.

"This begs the question, if all of the above is true, why haven't people gotten rid of the valve in their search for more fuel flow?"

Lots of people have including me. I paid CIS flowtech to do it 7 or 8 years ago. not everyone want to do this and if your car has to pass emission testing then you probably have to leave the functioning lambda system, catalytic converter, and air pump systems on there so it passes the emissions test

"Seems way easier that modifying the fuel head..."

>If you only remove the lambda valve you have to adjust (turning clockwise a little) the the six individual 3mm allen head spring tension adjustments (raising spring tension pushing down on the diaphrgm a little) under the 4mm button head screws next to the injector line banjo fittings to compensate.. If that is not done it will run too lean. It has to be done accurately for each injector on a flow bench to be done right. you can try doing it yourself woth the injectors in plastic water bottles and do it over and over until each injector fills the bottle equally but thats a risck if you don't know what you're doing.

That's just part of what CIS Flowtech does an excellent job of on a fuel head flow bench when modifying the lambda fuel head for more fuel flow across the range to get more fuel at higher rpms with higher than stock boost.

You can use an rpm switch controlling a vacuum solenoid in the boost pressure line going to the bottom of the CPR to keep the AFR's from being too rich during the initial onset of turbo boost in the midrange rpms with a CIS fuel head that has been modified to inject a lot more fuel than stock.
That will greatly improve drivability and fuel mileage with a 20%-30% higher flowing modified CIS fuel system..

Call Larry at CIS Flowtech when he's not too busy to talk to you. He likes to talk about fishing too...

Last edited by JFairman; 11-18-2014 at 08:58 AM..
Old 11-18-2014, 08:56 AM
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