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BlueDragon
07-24-2010, 03:34 PM
Okay I know this has been done before, and I think there used to be a thread on it but it must be gone because I searched and searched... here and at alltrac.net finding a few references but no thread.

So not being able to find out how exactly people have done this I hooked up my LED hot side to the T-VIS wire coming from the ECU and then grounded the other. I guess I need to find out first off if this is right or not before I even go into what T-VIS is or is not doing and when, but it just does not seem to work correctly.

karl
07-24-2010, 04:46 PM
ECU grounds the TVIS to activate it. you effectively have the LED lighting (solenoid acting as a pullup resistor when the ECU is not grounding/activating it) when TVIS is not active.

connect your LED to 12v in the cabin and run a wire back to the ECU side. when the ECU grounds the solenoid, the LED will turn on.

karl
07-24-2010, 04:46 PM
double post.

Sang
07-24-2010, 05:19 PM
Mine turns off when TVIS is activated. Does an LED light have polarity? I don't know shit about electrical systems, but I figured if the ecu sent power to TVIS when closed, it'll light the LED, and when grounded it will turn the LED off.

Oh well, lol

BlueDragon
07-24-2010, 07:00 PM
well thats not a good sign... is it making the t-vis work incorrectly? cause it turns on and stays lit after about 2200 rpm. Is it being hooked up this way causing it not to work or do I have another problem?
I will switch it today either way, just wondering. Thanks a-lot for the advice.
Sang I saw that from someone else on alltrac.net or an mr2 board or something as well. maybe you should re-wire yours as well?

Sang
07-24-2010, 08:08 PM
maybe you should re-wire yours as well?

Why? T-VIS itself looks to be functioning just the same, indication light only seems to be backwards, which I've gotten used to seeing by now. And ever since I took active control over it via an RPM switch, daily driving has never felt better.

BlueDragon
07-24-2010, 08:59 PM
Yeah it looks like I will have to do the same using my MAP-ECU because hooking it up this way makes it run like total crap... the light comes on then i press the gas it all and the light goes out, but the car stutters like no other, this is not right.
Damn damn damn my 200th cut solder shrink wrap coming up...

---------- Post added at 07:59 PM ---------- Previous post was at 07:56 PM ----------

do you completely cut it from the ecu and just connect it to the switched ground output of the rpm switch/MAP-ECU?

karl
07-24-2010, 10:11 PM
Mine turns off when TVIS is activated. Does an LED light have polarity? I don't know shit about electrical systems, but I figured if the ecu sent power to TVIS when closed, it'll light the LED, and when grounded it will turn the LED off.

Oh well, lol

yes, it has an anode and a cathode. it's a diode, so it will only pass current in one direction.

yours turns off when TVIS is on because the ECU is pulling the power source for the LED to ground. when it's not activated, the coil in the solenoid is acting as a pullup resistor to 12v, lighting the LED.

it really doesn't matter which way you have it hooked up. LEDs draw so little current that they will not alter how the system works regardless of how it's hooked up.

i was actually just about to start soldering together the boost switch for my TVIS.

Sang
07-24-2010, 10:38 PM
]do you completely cut it from the ecu and just connect it to the switched ground output of the rpm switch/MAP-ECU?


IIRC - Mine is cut completely. The RPM switch is soldered in place of the ECU. When the switch reaches the RPM set point, it'll ground out whatever it's connected to.

BlueDragon
07-25-2010, 12:09 AM
Well I have just had it hooked up both ways and I can say by experience it does alter how it works for some reason...

---------- Post added at 11:09 PM ---------- Previous post was at 09:50 PM ----------

http://www.celicatech.com/forums/showthread.php?t=30959&highlight=t-vis

very confused now... what cars do you guys have?? neither of your profiles has it.

Sang
07-25-2010, 05:05 AM
Gen2 3SGTE in a '91 MR2.

karl
07-25-2010, 06:35 PM
x2

as i said though, the LED can't physically draw enough current to change how the solenoid operates. something else must be going on there.

---------- Post added at 05:35 PM ---------- Previous post was at 05:34 PM ----------

x2

as i said though, the LED can't physically draw enough current to change how the solenoid operates. something else must be going on there.

BlueDragon
07-25-2010, 06:54 PM
well.... i unhooked it and its fine now so down to the only thing that changed I think I will stick with my own experience on this one....

ChrisD
07-26-2010, 04:58 PM
Thread is not gone, it is right here: http://www.celicatech.com/forums/showthread.php?t=20309&highlight=tvis

Although usually this stuff doesn't get posted here, mostly in the "tuning" type forums, so that might be why you missed it.

Hookecho
07-26-2010, 09:00 PM
Nevermind.

BlueDragon
07-26-2010, 11:19 PM
well I did a search of the whole forum so I dunno how I could miss it unless I am searching incorrectly.
also to karl I am not trying to be disrespectful, I have removed the led completely from the circuit and it is still acting funny, I hope I have not fouled my ECU or VSV... I am going to get up under it and check all the vac hoses on the actuator and vac tank... and make sure i got the pin all the way back in the harness but I am sure I did, but it never hurts to double check.
The MAP-ECU has an led indicator for its switched rpm output so I should not need this anymore anyhow. I already hooked it up for turbo vsv/knock response monitoring, works like a charm I am not getting any response but the car is stumbling terribly till about 4000 rpm and over 7psi boost very weird sigh