tricking the ACV
09-23-13, 01:30 AM
#1
TyrannosaurusRX7
Thread Starter
tricking the ACV
good evening, which side of the hose do I cap? is it the one going to the air pump or the hose going to ACV? Please help.
Thanks.
Thanks.
09-23-13, 10:27 AM
#2
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what are you trying to do?
09-25-13, 11:09 PM
#5
TyrannosaurusRX7
Thread Starter
1988 S4 NA, everything stock except with a blocked EGR valve, pulsation dampener replaced with a bolt and now a capped ACV. Do I just leave the smog pump uncap? your input will be highly appreciated.
Last edited by esjoson1126; 09-25-13 at 11:10 PM. Reason: more info
09-26-13, 12:12 AM
#6
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the air pump air needs to go into the ACV or you can try putting it directly into the cat
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09-27-13, 11:45 AM
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let me define a few terms. Mazda takes the air pump air into the ACV and then the ACV can route the air to one of three places, depending on RPM and throttle position
"Relief" this is the default position of the ACV, the air pump air is just relieved into the atmosphere, the 1st gen, and FD just put the air back into the air cleaner, FC has a tube to the front of the car.
"split air" this is when the air pump air goes though the big tube to the main cat under the car. the air is split between the two bricks of the cat. its mostly used on deceleration/5th gear.
"Port air" this is when the air pump air is going to the exhaust ports. the stock emissions control uses port air for everything under about 2500rpm, although it depends on throttle position. a proper running car is in port air during an emissions test.
the ACV has two plungers in it. the first plunger, chooses between relief and the second plunger. the second plunger chooses between split air and port air.
the engine MUST have the extra air pump air added to the exhaust somewhere, and so you either need to make the stock system function properly, or shim the ACV so its in port air, or something, otherwise it won't pass
"Relief" this is the default position of the ACV, the air pump air is just relieved into the atmosphere, the 1st gen, and FD just put the air back into the air cleaner, FC has a tube to the front of the car.
"split air" this is when the air pump air goes though the big tube to the main cat under the car. the air is split between the two bricks of the cat. its mostly used on deceleration/5th gear.
"Port air" this is when the air pump air is going to the exhaust ports. the stock emissions control uses port air for everything under about 2500rpm, although it depends on throttle position. a proper running car is in port air during an emissions test.
the ACV has two plungers in it. the first plunger, chooses between relief and the second plunger. the second plunger chooses between split air and port air.
the engine MUST have the extra air pump air added to the exhaust somewhere, and so you either need to make the stock system function properly, or shim the ACV so its in port air, or something, otherwise it won't pass
09-27-13, 09:24 PM
#10
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remove it from the engine, and you'll see that each valve is held on with screws, take these off, and you can see there is a lip where you can place a shim to keep the plungers where you want em.
anything that holds it open is good, nuts, bolts, rocks, etc
put it back on the car, and make sure no air comes out of the vent, which is the big hose that faces the right side of the car, and you should be good.
shop manual is here Foxed.ca - Mazda RX-7 Manuals
anything that holds it open is good, nuts, bolts, rocks, etc
put it back on the car, and make sure no air comes out of the vent, which is the big hose that faces the right side of the car, and you should be good.
shop manual is here Foxed.ca - Mazda RX-7 Manuals
09-30-13, 02:58 PM
#11
TyrannosaurusRX7
Thread Starter
failed again. smog tech guy explained to me that I have an incomplete combustion. Excess gas needs to "recirculate" he asked me if I checked my EGR. my egr's diaphragm is broken and cannnot hold pressure. It's expensive and very difficult to find a new or used egr for my S4 NA. If it's definitely going to pass emission I will buy it. anybody out there who have experienced my dillema please share your wisdom. Thank you. I have tried all the cheat sheet. I am 4 points away from passing, HC reading is 71 max is 67.
09-30-13, 03:14 PM
#12
at idle? if it's an S4 lean out the variable resistor a hair(counterclockwise 1/8 turn) and warm up the car more.
you're going to fail when it comes time to test the EGR, i wouldn't even mention it to the tech as he may or may not actually test it, if he does you're screwed. i don't even find EGRs that work anymore, they're ALL cooked now.
you're going to fail when it comes time to test the EGR, i wouldn't even mention it to the tech as he may or may not actually test it, if he does you're screwed. i don't even find EGRs that work anymore, they're ALL cooked now.
09-30-13, 10:33 PM
#13
TyrannosaurusRX7
Thread Starter
R.E. thanks for responding. I have fully leaned my variable resistor but that didn't work either. He said the car is running rich because of incomplete combustion. He said replace the egr to help complete the combustion process. A lot of unburnt fuel that makes it rich even if I lean out my V.R. is that true?
10-01-13, 10:09 AM
#14
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the variable resistor only effects idle, so if you're over 1024rpm it won't do anything.
i am assuming you are doing the dyno test, and if yes, how is your o2 sensor? the car wants to be in closed loop during the test, so the o2 sensor matters
i am assuming you are doing the dyno test, and if yes, how is your o2 sensor? the car wants to be in closed loop during the test, so the o2 sensor matters
10-01-13, 11:05 AM
#15
make sure no air comes out of the vent, which is the big hose that faces the right side of the car, and you should be good.
shop manual is here Foxed.ca - Mazda RX-7 Manuals
shop manual is here Foxed.ca - Mazda RX-7 Manuals
You can also apply vacuum to the rear nipple of the ACV. That should open the port air valve as much as possible.
10-03-13, 05:00 PM
#16
TyrannosaurusRX7
Thread Starter
I have tried several vendors already online and even mazdatrix, nobody carries the infamous EGR Valve. Anybody out there willing to sell their working EGR valve? please help me save the 7.
10-03-13, 05:03 PM
#17
TyrannosaurusRX7
Thread Starter
in response to RXspeed 16. Yes I did put a tie on my actuator before, but it was only for a brief period of time. I didn't like the performance feedback.
10-04-13, 06:00 PM
#18
you can get them off rockauto but they're not exactly cheap. about 300 bucks.
http://www.rockauto.com/catalog/more...364&cc=1192340
the turbo valve should still work with the n/a but you will simply have to run the hose around to the backside. the heat shield can also be removed if it causes any interference issues.
does the car sound like it is misfiring, popping or otherwise? it may in fact be too lean and need to be richened up. the sweet spot is just lean enough to allow the engine to run smooth but not to the point that it hunts or hiccups.
worst case you can modify the AFM to at least get you by temporarily. drill out the blind cap on the AFM air bleed port but be careful not to drill into the screw under the cap. note how many turns it takes to bottom out and write it down(should be about 3.5 full turns). now with the above in mind you can lean out the mixture by backing the screw out or richening it up by turning the screw in.
http://www.rockauto.com/catalog/more...364&cc=1192340
the turbo valve should still work with the n/a but you will simply have to run the hose around to the backside. the heat shield can also be removed if it causes any interference issues.
does the car sound like it is misfiring, popping or otherwise? it may in fact be too lean and need to be richened up. the sweet spot is just lean enough to allow the engine to run smooth but not to the point that it hunts or hiccups.
worst case you can modify the AFM to at least get you by temporarily. drill out the blind cap on the AFM air bleed port but be careful not to drill into the screw under the cap. note how many turns it takes to bottom out and write it down(should be about 3.5 full turns). now with the above in mind you can lean out the mixture by backing the screw out or richening it up by turning the screw in.
Last edited by RotaryEvolution; 10-04-13 at 06:09 PM.
10-05-13, 02:37 PM
#20
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i've actually hooked up to the factory diagnostic ports during an emissions test, and its in closed loop and port air, so the O2 sensor and the ACV being in port are are the important things. the EGR should be off, so replacing it won't help, unless its a vacuum leak.
10-05-13, 06:39 PM
#21
generally they do a visual inspection even for dyno smogs and test functionality of the smog equipment including the EGR. most of the time this is the last thing they do after it passes the sniffer.
if they're comfortable with you they usually will just do a visual inspection.
if they're comfortable with you they usually will just do a visual inspection.
10-05-13, 08:45 PM
#22
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????
10-11-13, 07:27 PM
#24
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Been on the road for the last week will have a look asap . sorry I know its a bitch waiting . like I said not sure weather I have one or not ,,.
I know nothing about these tests but would it not work to build a plate with the proper fittings to let the exhaust recirculate all the time until the tests are over ??? or just build a mounting plate and attach any EGR valve .
I know nothing about these tests but would it not work to build a plate with the proper fittings to let the exhaust recirculate all the time until the tests are over ??? or just build a mounting plate and attach any EGR valve .
10-18-13, 12:15 PM
#25
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sorry can't find the valve I still think it is around if I find it I will post right away . good luck . if you have the stuff to work with I don't see why you can't make a mounting plate adapter and make almost any 50.00 valve work . you should be able to almost use the old one to make the adapter with .
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