flubyux2

i was reading thru my Haynes a min ago. in the Emissions system, it talkes about the Decel control system. it consists of the Dashpot (to prevent throttle from closing abruptly), Anti-afterburn vavle (supplies air to intake man. during Decel), and the fuel cut switch (improves fuel econ. and prevents engine bucking during decel.)

in reguards to the Anti-afterburn valve, it shows there is a 1-way check valve mounted between the ACV and intake. the diagram says "youll have to remove the air control vavle to replace the intake manifold check valve-note the way it is installed so you dont put it in backwards"

my question is: what if you DID put it in backwards? it would prevent the air from being supplied to the intake during Decel right? i suspect this would cause a rich condition when you close the throttle abruptly (like when shifting)

you think this would result in Flames out the exhaust in a unrestricted exhaust?

btw, i just finished the TB mod, and waiting for the JB "rig" to cure. the Thermowax is gone (the passage on the TB itself was blocked anyhow), the dashpot, and cold start cam are all removed now, in addition to the 2ndary throttle plates and shaft (of course).

Gosh its good to be back in RX7-heaven, lots of changes to the board.

thanks
chris

flubyux2

Hailers, Keith (Irv) im sure you know something about this

HAILERS

Its close to impossible to install it backwards. There is no recess in the acv for the check valve. There is a recess in the intake manifold. There are only three fasteners holding the acv on the engine. You might take it off and see if the check valve is torn etc. There is a check out for a good or bad check valve in the online manual that does not require the removal of the acv. You check for backflow from the exaust by holding your finger over the inlet hose from the air pump. Only a really talented person could put one in backwards. EDIT; If it were blocked, I suppose it would keep what is called Port Air from mixing with the exaust which would contribute to the backfiring problem. But the way I understand the working of the aav, is that it feeds air pump air into the intake manifold upon deceleration, which is a seperate path than the previously mentioned check valve. That aav port is a seperate path.

flubyux2

lol, talented.

if it results in extra flames, i might try it just for kicks. it looks like there is a lip on the valve itself, and would need to be shaved off in order to install it backwards.

you think anything bad would come of this?

im just bored cuz i cant put my TB back on the car yet, can you tell??

thanks
chris

HAILERS

Here's a simplified schematic of the ACV. You can see the check valve is located where it says Port Air. The AAV , anti afterburn valve is located neat the top. You can see if a vac is applied to it, its valve opens and lets the air pump air travel to the intake , where I assume it leans out what mixture is there. JPG:

flubyux2

yea thats pretty much wht it does. the diagram that applies to my car is on 165.

its almost like an internally dumped BOV. it opens when you have maximum vaccum (idle or decel in gear) and allows air to flow from the air pump, thru ACV, into the intake. yea it would lean out the mixture so that its not overly rich. that means all the fuel would be burned up before it exits the tail pipe= no flames :o(.

looks like the releif valve have to be open before the AAV can work. i suppose i could disable that if i wanted extra flames. the only thing that it supplies is the Split air and the Port air... and my Split air is not operable (no main cat), and the port air...that wouldnt be able to get out if the check valve was reversed. it would be forced out the Split air, thru that little bypass under the Split air Solenoid valve

HAILERS

If you did not want any air pump air going any where, the easiest way to do that, is just take the BLUE connector off the Relief Solenoid. Then the Relief valve inside the acv will stay open and let all the air pump air go to the silencer. Now thats something that Flubyux2 might look into. Run the car at idle and remove the large exaust hose from the acv. Put your finger near the exaust port and feel for air. There might be a small amount coming out. Then pull the Blue connector off the relief solenoid. You should feel considerably more air exiting. If this does not happen, write back.

flubyux2

yea, that was my assumption. coincidentally, i broke the nipple off that same solenoid, so i know for sure that it works, cuz i tested it while it was out of the car. well, i guess just unplugging the electrical connector and letting it dangle would render the whole ACV system inoperable eh?

all i really need the Air pump for is to operate my 6PI, i prefer this over wiring them open.

Thanks bud, its good to know i can get some quality techincal conversation besides "what kind of muffler should i get" and "do these wheels look gay on my T2"

chris

HAILERS

If with the Blue connector on, you get a continuous blowing of air out the exaust of the acv, then do as Six Rotors suggested to someone recently, go to your radiator, and see if the two wires are on the connector at the bottom of the radiator. Left hand side. If that connector is off, then the relief valve in the acv will vent all the time, preventing any Port Air from getting there, or any Split Air to the cat or any AAV air getting to the intake manifold when it is needed.

flubyux2

yes, tahts right. the same thing happens if you put a jumper wire into the Exhaust overheat connector under the pass.side seat. but that would probably result in a "Exhaust Overheat" light on the waring cluster too.

would the Radiator sensor trick result in an "engine overheat" light of some kind? it seems these sensors check whether or not the engine/exhaust is super hot due to Excessive O2 (sort of like lean condition, results in super hot exhaust) so it would stop dumping fresh air into the exhaust, and allow it to be rich and cooler, correct?

HAILERS

The check valve jpg:

flubyux2

oh...


nevermind the 'shaving the lip' idea. it looked plastic in the Haynes book...damn black and white photos. then again, i just realized, if it WAS plastic, it would melt.

"GOD im such an IDIOT!" Tommy calahan, Junior.