Hi everyone, ive done a search but it didnt result to much help. From what i gathered, fluctuating idle is result of the PCV valve. BUT there is a Half black Half Grey valve that is labled on the hose diagram that is plastic that is coming from the oil filler neck directly to the UIM AND then there is a "Solinoid (Purge Control)" (Sol. K). The solinoid has a Metal check valve in it going to the UIM.

NOW... what is the cause of the idle problem? has someone fixed it? Can the Check valve from the oil neck be the reason the idle is fluctuating? or could it be the solinoid? I think i have eliminated it down to these two things but dont know what to do to go about fixin the problem. Please help.

Thanks in advance
Huy

 

i hope on a shooting star that this is possibly the only thing wrong with my car and causing it to idle like it has been. when i did my hose job the metal check valve didnt seem to blow through right so i replaced it with a generic one (or maybe it was the one good mazda check valve - i cant remember).
i reused the same PCV though...
anyways...any info y'all can give concerning the possible effects that the malfunction of any of these parts would cause would be very helpful to me and apparently to Huy as well as he's having an idle problem too...

Huy, you might look into the FSM to see how to test the purge control solenoid and see if its up to spec

 

It could be a number of things. If it were that easy to narrow it to a couple of things, there wouldn't be rotary specialists out there.

 

no one is asking why there is a fluctuating idle
the question is what does the PCV and the related solenoid and metal check valve effect and how does it all interact and work. THAT can be explained....

 

How does it fluctuate ?
My little experience is Clutch Switch.

This is a switch in front of the clutch pedal. It stick out when the clutch is pushed in.
It suppose to stick out 1/2 inch. Mine stick out 1/4 inch. So check it, maybe it help, plus its easy to check, just go under and look

Let me know,
Reza

 

From what I understand it releases presure from the crankcase? I have had idle problems since I took my car in for the 60,000 mile workup from Mazda. After light driving, I would shut the car down and when I started it a few hours later the idle would bounce around momentarily. I have the car at MZM performance now and they called and said the PCV had been "blocked off". I told them to put a new valve on which is inexpensive. That must be the source of my idle problems. I'll let you know soon.

I believe it is only required when you have the stock turbos, if you convert to single there is a block off plate.

 

good luck homie. i hope you have an easier time finding a solution than i am having. please keep us updated if you find the cure.

 

Hey Huy,

Is that Diana as your avatar? I've seen it a million times, and I was sitting here reading your ?, and was like, damn that chick's pretty hot...then Iwas like damn, she looks kinda familiar

 

Yah thats her, im trying to pick on her, but its not really working...

and reza - The fluctuation is on two automatics that i know of and its on suganuma's 5 speed.... so its obviously NOT specific for 5 speed, cuase both the autos have this problem. The idle will slowly calm down from a cold start, and i can only figure that is the AWS makeing the idle go funky, but slowly it will stop fluctuating, and the second the gas, or tis put into gear, anything at all, the idle returns and its up in the 1000+ rpms. I dont remeber what Suganuma's was idleing at, but his car was simply dying if it wasnt gassed.... no idea... help please
Thanks
Huy

 

PCV = Positive Crankcase Ventilation. It's a smog valve used to scavenge and return unburned fuel under valve covers/crankcases back into the intake on piston engines. Serves the same function on the rotary. I can't see it causing idle problems unless it's disconnected and a vacuum leak occurs. I would not remove it, as it helps prevent excess oil contamination by fuel.

 

http://www.rx7turboturbo.com/robrobinette/pcv.htm

this will answer your question

As for the purge control solenoid, what it does is that it let the gases that accumulated in the charcoal canister go in the UIM. The gases that accumulated in the charcoal canister are from the fuel tank. The air in the fuel tank, which is in fact fuel vapor, gets caught in the canister to make sure the fuel tank doesn't pressurise with fuel vapor and sometimes, you need to free the gas that accumulates in this canister. (this is what the PC is for). I doubt this is your problem.

puma

 

I had a fluctuating idle problem, which was simply fixed.. The idle screw was set all the way down, upping it fixed the problem nicely, I now have a solid 800rpm idle..

Don't know if thats what your problem was (or if someone suggested that)..

 

damn, how do i do to delete a post? it doesn't work...

 

well you can remove it but not bypass it. n 1995 cars, there were no PCV. Just had a oil catch can like on robinette's site.

 

Puma, the link you sent me doesnt show the same PCV valve as what im thinking and what the vac hose diagram shows, the vac diagram shows the PCV is almost looks a check valve coming from the oil filler neck. The one your talking about (Robs site) doesnt seem like its the same one. are there two diffent things named PCV??? thanks again
Huy

 

no, it's the same thing. It is grey and black i think. It is in fact a sort of check valve. It goes from the oil filler neck to the UIM, with some big tubing (something like 8mm)

i am not talking about the metal one, that one goes on the purge control.