Can you figure out my AC problem? Videos Inside
11-27-13, 08:18 PM
#1
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Can you figure out my AC problem? Videos Inside
https://vimeo.com/80513431
https://vimeo.com/80513393
What's causing it?
I have a 93 rx7 5 speed power FC tuned by Steve Kan
Recently every time I turned on the ac the idle would go down (~ 500 rpms ) instead of a little above 1000 rpms. I thought it could be due to the harness been cut ( by me due to me going simplified sequential and no emissions) so I replaced the harness but now this is happening. Any ideas? I replaced the tps, throttle body and idle speed valve.
Alex
https://vimeo.com/80513393
What's causing it?
I have a 93 rx7 5 speed power FC tuned by Steve Kan
Recently every time I turned on the ac the idle would go down (~ 500 rpms ) instead of a little above 1000 rpms. I thought it could be due to the harness been cut ( by me due to me going simplified sequential and no emissions) so I replaced the harness but now this is happening. Any ideas? I replaced the tps, throttle body and idle speed valve.
Alex
11-27-13, 08:31 PM
#2
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The ISC is what controls idle speed for three settings:
(1) idle with no AC or electrical heavy load
(2) heavy electrical load
(3) AC load.
The rpm set values can be set with the Commander.
If the ISC solenoid gets too dirty, or there are air leak in the intake somewhere, or other things affecting these three, the idle can do two things from the norm; drop too low then try to recover
or rev too high then drop off. Both of these can cause cycling as you are having. This is caused by either too much or too little air entering through the throttle body separately than the ISC and the limited control of the ISC to compensate.
Normal procedure is to make 1/4 turn adjustments to the Air Adjusting Screw on the throttle body to try and resolve the problem. Either more or less air.
The clue will be from how the ISC works for #1 and #2 as listed above.
If stopping and the revs drop to almost dying before recovery, it needs more air.
If it drops too slowly, then less air.
If neither more or less air helps, remove the ISC solenoid and clean it. Check for air leaks like bad hoses. Start over again.
Post your mods and attach the map as there are other things that might be off.
(1) idle with no AC or electrical heavy load
(2) heavy electrical load
(3) AC load.
The rpm set values can be set with the Commander.
If the ISC solenoid gets too dirty, or there are air leak in the intake somewhere, or other things affecting these three, the idle can do two things from the norm; drop too low then try to recover
or rev too high then drop off. Both of these can cause cycling as you are having. This is caused by either too much or too little air entering through the throttle body separately than the ISC and the limited control of the ISC to compensate.
Normal procedure is to make 1/4 turn adjustments to the Air Adjusting Screw on the throttle body to try and resolve the problem. Either more or less air.
The clue will be from how the ISC works for #1 and #2 as listed above.
If stopping and the revs drop to almost dying before recovery, it needs more air.
If it drops too slowly, then less air.
If neither more or less air helps, remove the ISC solenoid and clean it. Check for air leaks like bad hoses. Start over again.
Post your mods and attach the map as there are other things that might be off.
11-27-13, 08:47 PM
#3
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I closed the air screw completely and nothing. I tried three idle air valves. I'm guessing the next step is air leaks? The idle is perfect with out load and it goes from 750 to 825 with the interior and headlight lights on I did notice that if I unplug the isc or air idle valve and then turn on the AC it just goes down to 500 rpms
11-27-13, 08:52 PM
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Mods:
Air pump removed
Jdm upper and lower intake manifold
Jdm tb modified for Usdm use
Simplified sequential
All emissions removed
Jdm ypipe
Bonez cat
Powerfc
Air pump removed
Jdm upper and lower intake manifold
Jdm tb modified for Usdm use
Simplified sequential
All emissions removed
Jdm ypipe
Bonez cat
Powerfc
11-27-13, 10:30 PM
#5
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I closed the air screw completely and nothing. I tried three idle air valves. I'm guessing the next step is air leaks? The idle is perfect with out load and it goes from 750 to 825 with the interior and headlight lights on I did notice that if I unplug the isc or air idle valve and then turn on the AC it just goes down to 500 rpms
Without the ISC plugged in and flowing more air, the AC load will naturally drop way low. Common auto knowledge/understanding.
You need to know/understand how things work and experiment with them.
I never preferred the stock idle values, especially with a modded engine.
Try this set and go through the relearn process, but first remove and clean the ISC solenoid.
9999
1400
1400
1400
800
900
1000.
Load your map!
11-27-13, 10:48 PM
#6
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I will load my map once I can try everything else you are explaining. I appreciate your help. Could the screw on top of the throttle body that adjusts the two top butterflies need to be adjusted.?
11-27-13, 11:19 PM
#7
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If it was opening them, the idle would be very high like an air leak.
You need to study the FSM (section F) about the TB functions.
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11-28-13, 09:27 AM
#8
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So I cleaned the darn idle speed valve for 1 hr reattached and same issue. I reset the tb per fsm and tried ur Powerfc numbers and nothing. I noticed something though when I closed the idle air valve and loosen the throttle line and pushed the throttle body flaps down with the idle speed valve connected the car was still idleing fine but as soon as I disconnected it the car died. I believe either the idle speed valve is stuck open and letting too much air at idle and under load or I have a leak. I guess my next step is to load a map
11-28-13, 10:35 AM
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powerfc maps
Zip file part 1 = This is as the car sits right now with the air idle screw backed up 1 turn and then 2 turns
Zip file part 2= This is after i stuffed a rag into the large (oval nickel size hole infront of the botton butterfly flap on the throttle body)
IT WORKED PERFECTLY! all i need to know is why is it a leak? or the idle air valve stuck open? how come stuffing the rag there stabilized the idle with AC on...
Zip file part 2= This is after i stuffed a rag into the large (oval nickel size hole infront of the botton butterfly flap on the throttle body)
IT WORKED PERFECTLY! all i need to know is why is it a leak? or the idle air valve stuck open? how come stuffing the rag there stabilized the idle with AC on...
11-28-13, 05:33 PM
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So I cleaned the darn idle speed valve for 1 hr reattached and same issue. I reset the tb per fsm and tried ur Powerfc numbers and nothing. I noticed something though when I closed the idle air valve and loosen the throttle line and pushed the throttle body flaps down with the idle speed valve connected the car was still idleing fine but as soon as I disconnected it the car died. I believe either the idle speed valve is stuck open and letting too much air at idle and under load or I have a leak. I guess my next step is to load a map
11-28-13, 05:40 PM
#11
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Zip file part 1 = This is as the car sits right now with the air idle screw backed up 1 turn and then 2 turns
Zip file part 2= This is after i stuffed a rag into the large (oval nickel size hole infront of the botton butterfly flap on the throttle body)
IT WORKED PERFECTLY! all i need to know is why is it a leak? or the idle air valve stuck open? how come stuffing the rag there stabilized the idle with AC on...
Zip file part 2= This is after i stuffed a rag into the large (oval nickel size hole infront of the botton butterfly flap on the throttle body)
IT WORKED PERFECTLY! all i need to know is why is it a leak? or the idle air valve stuck open? how come stuffing the rag there stabilized the idle with AC on...
Here is another test, what are the two TPS voltages and are they in stock range?
(09) Use the PFC Commander to check the TPS voltages. Go to the ETC. MENU -
Sensor/SW Check screen. Look at the VTA1 and VTA2 values. Note them at
closed and open throttle positions.
Mazda's Standards are:
VTA1: closed 0.10 to 0.70. open 4.2 to 4.6.
VTA2: closed 0.75 to 1.25. open 4.8 to 5.0.
This has a great affect on idle quality.
Other possible problems: main throttle cable or cruise control cable not allowing throttle to close all the way.
11-28-13, 05:53 PM
#12
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Just looked at your logs. TPS voltage is good.
You can see when the AC oscillation goes high near 2000 rpm, fuel cut happens.
It appears you have an air flow problem that is not within the range that the ISC can handle.
You can see when the AC oscillation goes high near 2000 rpm, fuel cut happens.
It appears you have an air flow problem that is not within the range that the ISC can handle.
11-28-13, 06:24 PM
#13
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That opening that you mentioned is the source for the air that goes through the ISC solenoid. It is suppose to be there. Maybe your throttle adjusting screw (main butterfly valves) are opened too much.
YOU MEAN THE TWO TOP ONES? I tried stuffing a rug against all three valves and nothing still surges...
Here is another test, what are the two TPS voltages and are they in stock range?
(09) Use the PFC Commander to check the TPS voltages. Go to the ETC. MENU -
Sensor/SW Check screen. Look at the VTA1 and VTA2 values. Note them at
closed and open throttle positions.
Mazda's Standards are:
VTA1: closed 0.10 to 0.70. open 4.2 to 4.6.
VTA2: closed 0.75 to 1.25. open 4.8 to 5.0.
This has a great affect on idle quality.
VTA1: .4. Open 4.4
VTA2: .99 open 5.0
Other possible problems: main throttle cable or cruise control cable not allowing throttle to close all the way.
YOU MEAN THE TWO TOP ONES? I tried stuffing a rug against all three valves and nothing still surges...
Here is another test, what are the two TPS voltages and are they in stock range?
(09) Use the PFC Commander to check the TPS voltages. Go to the ETC. MENU -
Sensor/SW Check screen. Look at the VTA1 and VTA2 values. Note them at
closed and open throttle positions.
Mazda's Standards are:
VTA1: closed 0.10 to 0.70. open 4.2 to 4.6.
VTA2: closed 0.75 to 1.25. open 4.8 to 5.0.
This has a great affect on idle quality.
VTA1: .4. Open 4.4
VTA2: .99 open 5.0
Other possible problems: main throttle cable or cruise control cable not allowing throttle to close all the way.
NOW I JUST CHANGED MY THROTTLE BODY TO A JDM ONE 2 MONTHS AGO AND I HAD TO REMOVE THE SPRINGS AND REINSTALL THE SMALL CLAWS THAT GRAB THE ACCELERATOR AND CRUISE CABLES. I FEEL A LOT OF RESITANCE WHEN TRYING TO FULLY CLOSE AND OR OPEN THE BUTTERFLIES ALMOST IMPOSSIBLE TO GET THEM CLOSED ALL THE WAY.
11-28-13, 07:55 PM
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If the throttle does not completely close, that allows more air flow, but if you disconnect the ISC solenoid and it will not idle at #1, then it is OK.
Question, when the AC is turned on, is the compressor actually turning?
Question, when the AC is turned on, is the compressor actually turning?
11-28-13, 08:02 PM
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if the throttle does not completely close, that allows more air flow, but if you disconnect the isc solenoid and it will not idle at #1, then it is ok.
I don't know what you mean if the car is idleing then i unplug the isc it still idles...
Question, when the ac is turned on, is the compressor actually turning?
I don't know what you mean if the car is idleing then i unplug the isc it still idles...
Question, when the ac is turned on, is the compressor actually turning?
11-28-13, 10:51 PM
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I still don't get #? And jdm? But could it be the fast idle cam ? How else can I reduce air?! Maybe I'll play with the tps, fast idle . I unscrewed the dash pot, tb set screw next to it and lossened the throttle cable completely and nothing still to much air going in could it be fast idle wax? Or bad. MAP?
12-01-13, 12:06 PM
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Ok so what I did was stuffed that rag on the larger hole which does not lead to the isc... It leads to the upper intake manifold and everything worked perfect with the isc screw completely closed. I also backed it up 1 and 2 turns and still perfect. I then disconnected the isc and the engine died. I removed the rag and raised the idle with the air bleed with the isc disconnected perfect idle but would lower with electrical load and ac. Can someone tell me how to rule out the isc or air leak?
12-01-13, 04:06 PM
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I'm trying to reinstall the oem ecu can someone help me? I have no idea where the ground goes to and where the black wire with a small plastic connector goes too... 93 5 speed rx7
12-03-13, 07:55 PM
#25
Chuck has given some good input. Please see this thread, https://www.rx7club.com/3rd-generati...needed-841706/ post #1, #20, #23, 27-28. I realize it doesn't directly cover A/C idle issues, but a lot of the principles apply.