Throttle body mod??? how
09-17-13, 01:06 PM
#52
then try lowering the idle set screw on the throttle body.
a semi stuck thermowax can also hold up the throttle plates on a fully warm engine. pull up on the thermowax cam and if the engine idles down properly when warm then the thermowax is your problem.
sometimes it takes a little while to bleed air out of the thermowax circuit and it will idle high until all the air has worked out of the system. but this generally only takes about 30 minutes to an hour of run time and topping off the coolant level. in some cases the thermowax was sticking and working it by hand freed it up, they are getting old after all.
a semi stuck thermowax can also hold up the throttle plates on a fully warm engine. pull up on the thermowax cam and if the engine idles down properly when warm then the thermowax is your problem.
sometimes it takes a little while to bleed air out of the thermowax circuit and it will idle high until all the air has worked out of the system. but this generally only takes about 30 minutes to an hour of run time and topping off the coolant level. in some cases the thermowax was sticking and working it by hand freed it up, they are getting old after all.
Last edited by RotaryEvolution; 09-17-13 at 01:08 PM.
09-17-13, 05:17 PM
#53
problem is without the bac it won't hold idle when cold if I do, it will hold 750 but then go up to 1000, I've removed everything associated with the thermowax and fast cam.
my throttle body is jdm so I know there is some difference in the way the secondary butterflies work, I've got those stock.
I really wanna get the bac valve working but I'm not sure what the problem is.
I only have 250 miles on break in so I figure as compression builds the idle issue will resolve itself
my throttle body is jdm so I know there is some difference in the way the secondary butterflies work, I've got those stock.
I really wanna get the bac valve working but I'm not sure what the problem is.
I only have 250 miles on break in so I figure as compression builds the idle issue will resolve itself
09-17-13, 05:32 PM
#54
sounds like normal operation to me. the BAC valve is doing the work of the thermowax when cold, when warm it is not needed and the idle within a "modified throttle body" range.
all that stuff serves a purpose, without it you just have to accept a happy median, which is normal idle when cold and high idle when warm.
as i said earlier, the BAC valve operating range is rather narrow and i think you're expecting too much of it.
all that stuff serves a purpose, without it you just have to accept a happy median, which is normal idle when cold and high idle when warm.
as i said earlier, the BAC valve operating range is rather narrow and i think you're expecting too much of it.
09-17-13, 06:10 PM
#56
Everyone is constantly selling BAC valves in the classifieds. You have no excuse to not find one for $10. They are all the same. The only difference is the inlet tube/elbow varies from turbo to NA. If you need to, you can loosen a set screw, and adjust the inlet as required. I know, I've done it.
Also, TB's are always for sale. Get a thermowax cheap off of one of those. You can easily test them by running it under hot water, then dunking it in cold water to see it expand and contract.
I have both these stock components working on my modified engine with an old standalone computer. My car starts, idles, and is immediately drivable whether it's 10 degrees out, or 90 degrees out.
Good luck.
PS
you can test the BAC right on the battery and see if it clicks. Then you know it's at least not stuck, and the problem could be the wiring.
Also, TB's are always for sale. Get a thermowax cheap off of one of those. You can easily test them by running it under hot water, then dunking it in cold water to see it expand and contract.
I have both these stock components working on my modified engine with an old standalone computer. My car starts, idles, and is immediately drivable whether it's 10 degrees out, or 90 degrees out.
Good luck.
PS
you can test the BAC right on the battery and see if it clicks. Then you know it's at least not stuck, and the problem could be the wiring.
09-17-13, 06:23 PM
#57
I know it works I've had it work by using a direct ground, why the ground made for it isn't working idk.
like that it'd just bounce at 1500 rpm during that test, so I know it works
I had a spare bac but accidentally sold it with an uim.
Now how I fix the wiring or whatever is wrong is my question
like that it'd just bounce at 1500 rpm during that test, so I know it works
I had a spare bac but accidentally sold it with an uim.
Now how I fix the wiring or whatever is wrong is my question
09-17-13, 06:55 PM
#58
key on the black/white wire should have 12v.
check continuity from the blue/green wire to ground on the engine and then check continuity from the pigtail to the ECU with the ECU connector disconnected, pin 2G. continuity to ground should be open, continuity to the ECU connector should be about 4-6 ohms, inspect the connectors for damage or pushed in pins..
check continuity from the blue/green wire to ground on the engine and then check continuity from the pigtail to the ECU with the ECU connector disconnected, pin 2G. continuity to ground should be open, continuity to the ECU connector should be about 4-6 ohms, inspect the connectors for damage or pushed in pins..
Last edited by RotaryEvolution; 09-17-13 at 06:59 PM.
09-17-13, 07:20 PM
#60
i don't think crossing them would do any harm but if you somehow applied voltage directly to the blue/green wire i could see it possibly damaging the driver inside the ECU. this isn't simply a "ground", it is a pulsed ground signal from the ECU, with rather delicate workings. just like it's not all that easy to blow out an injector driver, you could do it if you're not too careful and they work on the same basic principle as the BAC circuit.
the BAC valve is a load, without a load in between the ECU becomes the load and that is bad and how you let smoke out of components. (sorry, old mechanic jokes)
the BAC valve is a load, without a load in between the ECU becomes the load and that is bad and how you let smoke out of components. (sorry, old mechanic jokes)
Last edited by RotaryEvolution; 09-17-13 at 07:26 PM.
09-17-13, 07:21 PM
#61
Reversing the wires is no problem but touching them together is. The voltage at pin 2Q, BAC, (and not pin 2G, which is the TPS) should drop to about 2 volts or so w/key to start. W/key to on it will be close to 10 volts. If you see the large drop off w/key to start then the ECU driver for the BAC appears to be working.
09-17-13, 07:28 PM
#62
Reversing the wires is no problem but touching them together is. The voltage at pin 2Q, BAC, (and not pin 2G, which is the TPS) should drop to about 2 volts or so w/key to start. W/key to on it will be close to 10 volts. If you see the large drop off w/key to start then the ECU driver for the BAC appears to be working.
09-17-13, 07:31 PM
#64
No. Short to what? The Blue/Green wire is not really a ground wire and if it were short to ground then the BAC would be full open all the time. My BAC will buzz atter a fairly long drive. You could easily tell if the wire were shorting out.
Last edited by satch; 09-17-13 at 07:37 PM.
09-18-13, 11:56 AM
#67
why did i write out the test if you're going to just disregard it? you asked, we answered.
if the test comes out ok then you can try swapping the ECU if you have a spare and see if that makes a difference, or measure the voltage as satch mentioned which should tell you if the BAC is functioning to some degree.
if the test comes out ok then you can try swapping the ECU if you have a spare and see if that makes a difference, or measure the voltage as satch mentioned which should tell you if the BAC is functioning to some degree.
09-18-13, 12:54 PM
#68
why did i write out the test if you're going to just disregard it? you asked, we answered.
if the test comes out ok then you can try swapping the ECU if you have a spare and see if that makes a difference, or measure the voltage as satch mentioned which should tell you if the BAC is functioning to some degree.
if the test comes out ok then you can try swapping the ECU if you have a spare and see if that makes a difference, or measure the voltage as satch mentioned which should tell you if the BAC is functioning to some degree.
09-18-13, 04:13 PM
#69
I did do the the test , i wasn't avoiding it I do apologize if I have given anyone that impression.
voltage read 1 volt on both ends ecu and connector side , no difference, shortly after idling a bit both went down to .69
The black wire varied but was around 13v
Are these values normal ? The fsm refers to 2Q spec to be between 8-12v and mine was nowhere near that.
I cant swap ECUs, no extra and mine is chipped so I wouldnt use the spare even if it fixed my problem.
I did tweak throttle stop and adjusted the tps afterwords , but if anything I got it to drop 100 rpms but it still likes to idle over 1000 after a decel when warm.
I need a timing gun to check my timing , that's my next thing to do.
If my timing is advanced that would cause the higher idle I'd think
unrelated my temp gauge seems to be on the Fritz it stopped working again , idk what's up with it but I thought I had it fixed.
voltage read 1 volt on both ends ecu and connector side , no difference, shortly after idling a bit both went down to .69
The black wire varied but was around 13v
Are these values normal ? The fsm refers to 2Q spec to be between 8-12v and mine was nowhere near that.
I cant swap ECUs, no extra and mine is chipped so I wouldnt use the spare even if it fixed my problem.
I did tweak throttle stop and adjusted the tps afterwords , but if anything I got it to drop 100 rpms but it still likes to idle over 1000 after a decel when warm.
I need a timing gun to check my timing , that's my next thing to do.
If my timing is advanced that would cause the higher idle I'd think
unrelated my temp gauge seems to be on the Fritz it stopped working again , idk what's up with it but I thought I had it fixed.
09-18-13, 05:24 PM
#70
Idle is going to change depending on engine temp. There is not much you can do to alter the 1000+RPM idle. Let's make up some numbers as an example.
I want a 750RPM warmed up idle, but my engine is idling at 1000RPM. So what do I do? I back out the throttle screw so the idle drops to 750. Now the next day I come back and start the car, but the engine stalls out. Why? Idle is too low on the cold engine. So what do I do? Tighten the throttle screw. So now it's cold and can idle at 750. But then when it warms up? Back to 1000RPM
That's why we have a BAC and thermowax, to "hold" the throttle open when cold (or with accessory loads). There is no way to have the car idle 750 cold and hot without some type of idle assistance. That goes for any engine.
You can keep adjusting the idle via the screw all you want, but you won't really help anything.
Also... if the car is idling at 1000RPM (when warm) and you are looking for a BAC signal (voltage or whatever), you won't find one. The engine doesn't need to run the BAC valve at that point. Probably best to check everything on a cold engine.
I want a 750RPM warmed up idle, but my engine is idling at 1000RPM. So what do I do? I back out the throttle screw so the idle drops to 750. Now the next day I come back and start the car, but the engine stalls out. Why? Idle is too low on the cold engine. So what do I do? Tighten the throttle screw. So now it's cold and can idle at 750. But then when it warms up? Back to 1000RPM
That's why we have a BAC and thermowax, to "hold" the throttle open when cold (or with accessory loads). There is no way to have the car idle 750 cold and hot without some type of idle assistance. That goes for any engine.
You can keep adjusting the idle via the screw all you want, but you won't really help anything.
Also... if the car is idling at 1000RPM (when warm) and you are looking for a BAC signal (voltage or whatever), you won't find one. The engine doesn't need to run the BAC valve at that point. Probably best to check everything on a cold engine.
09-18-13, 05:31 PM
#71
Idle is going to change depending on engine temp. There is not much you can do to alter the 1000+RPM idle. Let's make up some numbers as an example.
I want a 750RPM warmed up idle, but my engine is idling at 1000RPM. So what do I do? I back out the throttle screw so the idle drops to 750. Now the next day I come back and start the car, but the engine stalls out. Why? Idle is too low on the cold engine. So what do I do? Tighten the throttle screw. So now it's cold and can idle at 750. But then when it warms up? Back to 1000RPM
That's why we have a BAC and thermowax, to "hold" the throttle open when cold (or with accessory loads). There is no way to have the car idle 750 cold and hot without some type of idle assistance. That goes for any engine.
You can keep adjusting the idle via the screw all you want, but you won't really help anything.
Also... if the car is idling at 1000RPM (when warm) and you are looking for a BAC signal (voltage or whatever), you won't find one. The engine doesn't need to run the BAC valve at that point. Probably best to check everything on a cold engine.
I want a 750RPM warmed up idle, but my engine is idling at 1000RPM. So what do I do? I back out the throttle screw so the idle drops to 750. Now the next day I come back and start the car, but the engine stalls out. Why? Idle is too low on the cold engine. So what do I do? Tighten the throttle screw. So now it's cold and can idle at 750. But then when it warms up? Back to 1000RPM
That's why we have a BAC and thermowax, to "hold" the throttle open when cold (or with accessory loads). There is no way to have the car idle 750 cold and hot without some type of idle assistance. That goes for any engine.
You can keep adjusting the idle via the screw all you want, but you won't really help anything.
Also... if the car is idling at 1000RPM (when warm) and you are looking for a BAC signal (voltage or whatever), you won't find one. The engine doesn't need to run the BAC valve at that point. Probably best to check everything on a cold engine.
without the thermowax the BAC valve is just fighting an uphill battle on a job it was never intended to take on alone.
all of my testing is done on a warm engine within idle specs, which yours is going to be out of so the BAC isn't going to be giving you an accurate reading. from the sound of it it is working, it's just not needed when the engine is hot. and without the thermowax it is doing the job of idling the engine while cold, which it shouldn't have to be doing.
#1) get a good TII thermowax and plumb it back in
#2) set the idle with the engine warm and BAC disconnected
this should give you a solid idle cold and warm.
in reality the thermowax does a hell of a better job at idle setting than the BAC valve does, it just can't do the fine corrections that the BAC can and takes on the bigger job of maintaining some consistency from cold to hot.
Last edited by RotaryEvolution; 09-18-13 at 05:40 PM.
09-18-13, 05:41 PM
#72
I'm gonna ground the initial set coupler on my next test.
the bac valve is disconnected as far as the connector goes, I'm simply testing wire voltage without it being connected
when it was connected it did absolutely nothing so dc'ing it made no change to idle , which is why I'm trying to see what's causing it not to work.
I don't want the thermowax , I don't want to run the coolant line to the TB.
I am the one who took it off to begin with
the bac valve is disconnected as far as the connector goes, I'm simply testing wire voltage without it being connected
when it was connected it did absolutely nothing so dc'ing it made no change to idle , which is why I'm trying to see what's causing it not to work.
I don't want the thermowax , I don't want to run the coolant line to the TB.
I am the one who took it off to begin with
09-18-13, 06:27 PM
#73
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This thread is full of facepalm.
In any event, his BAC isn't being overworked or worked at all for the simple fact that he can disconnect it at at any point with no change to the idle.
The less than 1V on a duty cycle controlled system didn't alert anybody else to the fact that this would mean the valve is running at a high duty cycle, but yet apparently not operating... at all? Remember folks, the lower the voltage, the more ground pulses, thus the higher the effective duty cycle of the valve. Yet.... no change.... ever.
Thermowax at this point is of no consequence to that issue.
The mechanical idle is likely set to high, with the TPS accordingly following suit which is the source of the "roaming" idle.
In any event, his BAC isn't being overworked or worked at all for the simple fact that he can disconnect it at at any point with no change to the idle.
The less than 1V on a duty cycle controlled system didn't alert anybody else to the fact that this would mean the valve is running at a high duty cycle, but yet apparently not operating... at all? Remember folks, the lower the voltage, the more ground pulses, thus the higher the effective duty cycle of the valve. Yet.... no change.... ever.
Thermowax at this point is of no consequence to that issue.
The mechanical idle is likely set to high, with the TPS accordingly following suit which is the source of the "roaming" idle.
09-18-13, 07:18 PM
#74
This thread is full of facepalm.
In any event, his BAC isn't being overworked or worked at all for the simple fact that he can disconnect it at at any point with no change to the idle.
The less than 1V on a duty cycle controlled system didn't alert anybody else to the fact that this would mean the valve is running at a high duty cycle, but yet apparently not operating... at all? Remember folks, the lower the voltage, the more ground pulses, thus the higher the effective duty cycle of the valve. Yet.... no change.... ever.
Thermowax at this point is of no consequence to that issue.
The mechanical idle is likely set to high, with the TPS accordingly following suit which is the source of the "roaming" idle.
In any event, his BAC isn't being overworked or worked at all for the simple fact that he can disconnect it at at any point with no change to the idle.
The less than 1V on a duty cycle controlled system didn't alert anybody else to the fact that this would mean the valve is running at a high duty cycle, but yet apparently not operating... at all? Remember folks, the lower the voltage, the more ground pulses, thus the higher the effective duty cycle of the valve. Yet.... no change.... ever.
Thermowax at this point is of no consequence to that issue.
The mechanical idle is likely set to high, with the TPS accordingly following suit which is the source of the "roaming" idle.
http://en.wikipedia.org/wiki/Pulse-width_modulation
Last edited by RotaryEvolution; 09-18-13 at 07:22 PM.