Grounding VTC
#1
Grounding VTC
So I'm going to ground my VTC and I seen on craig braces page that he used a spliced/bullet connector but i wanna solder my ground wire in thats ok as well right..........
#3
#9
#15
What information are you looking for.
Basically the VTC solinoid is activated by the ECU. The Solinoid has constant power, and the ground is switched by the ECU at RPMS off idle that have a higher throttle point. When the solinoid is activated, it presurizes the VTC by oil pressure. The oil pressure rotates the inside of the VTC 10 degrees to advance the Intake cam timing.
Nissan used the VTC to increase mid range torque, and high end horse power without sacraficing the idle and emmisions.
The ground wire from the two VTC solinoids are hooked together already, so if you ground one of them, they will both be grounded and activated. The problem is, this can also cause idle problems. But the VTC clatter should go away.
Basically the VTC solinoid is activated by the ECU. The Solinoid has constant power, and the ground is switched by the ECU at RPMS off idle that have a higher throttle point. When the solinoid is activated, it presurizes the VTC by oil pressure. The oil pressure rotates the inside of the VTC 10 degrees to advance the Intake cam timing.
Nissan used the VTC to increase mid range torque, and high end horse power without sacraficing the idle and emmisions.
The ground wire from the two VTC solinoids are hooked together already, so if you ground one of them, they will both be grounded and activated. The problem is, this can also cause idle problems. But the VTC clatter should go away.
#17
I soldered the ground to the solenoid wire as well, but I also put it on a switch because the engine runs a little lumpy during warm up in colder temperatures. Anyone else have that issue? At the time I grounded mine, I didn't read any posts with others having that issue, and haven't bothered looking up much on it since. It's not bad by any means, the vibration is hardly noticeable, but the exhaust definitely has a lumpy sound, as opposed to that nice smooth hum I was used to. I took the splice I already made into the solenoid wire, ran it through the firewall, and mounted a switch on the console, above the shifter where the coil holders are.
#18
Yeah I ran into that with my car too for a long time. (before I rebuilt the VTCs).. My car had a hard time idling properly when I had the VTCs grounded, so I'd leave them off in the winter when the car was always 'grumpy' on cold mornings. I'd reground them in the summer when it idled better and I had no power from heat soak anyway.
#19
Interesting. Good to hear it's normal and not just me. I haven't had too much idle trouble, though I did have trouble with the coolant temp sensor contacts in the harness getting corroded, which lead to coolant temp sensor like symptoms, namely stalling. I chased it around for a while, including readjusting the TPS and cleaning the idle air control. Since then it sometimes stalls during warm up, when I push in the clutch - the idle drops down below normal and ususally picks itself back up, but seems to go lower during warm up and sometimes doesn't catch itself. Lately it's been better though and I haven't touched anything.
#20
You might just have to replace that/those connector/s. Nissan usually sells them with like 6" leads. peel back the rest of the wiring harness, then cut and solder & shrink wrap.
I suggest replacing the TPS, IACV, and temp sensor connectors in your case...
My car won't idle for sheit now with AC on after I ported the heads. I think the engine just needs too much airflow that the IACV can't compensate enough. with AC off, it runs fine although it will dip a bit low when I first let off the gas. with the AC on, it'll just shut off every time I push the clutch in. CONSULT says the thing is working fine electrically.. so I think it's just a matter of not enough airflow. I guess I need to take it apart and drill out the openings a bit to increase the throughput of idle air....
I suggest replacing the TPS, IACV, and temp sensor connectors in your case...
My car won't idle for sheit now with AC on after I ported the heads. I think the engine just needs too much airflow that the IACV can't compensate enough. with AC off, it runs fine although it will dip a bit low when I first let off the gas. with the AC on, it'll just shut off every time I push the clutch in. CONSULT says the thing is working fine electrically.. so I think it's just a matter of not enough airflow. I guess I need to take it apart and drill out the openings a bit to increase the throughput of idle air....
#21
IMHO putting them on a switch is the way to go and I think it is easier because you can do all the wiring inside the car vs. hacking up the harness in the engine bay.
Mine had troubles idling at first when it was grounded, eventually they learn but having them on the switch is nice. Plus depending on their condition you can leave them ungrounded and then if they start clacking ground them for 10 seconds or so and then unground them and they'll be quiet for a while. If you have a 5spd car try to find an Automatic Transmission switch (the Power/Comfort switch) and wire them to that for a clean factory look (you'll only use one side of the switch). If you have a FSM or if some of the old links work you can find out how. I probably did a write up, hopefully I wrote the colors in the post instead of just posting a picture that is probably long gone now
Mine had troubles idling at first when it was grounded, eventually they learn but having them on the switch is nice. Plus depending on their condition you can leave them ungrounded and then if they start clacking ground them for 10 seconds or so and then unground them and they'll be quiet for a while. If you have a 5spd car try to find an Automatic Transmission switch (the Power/Comfort switch) and wire them to that for a clean factory look (you'll only use one side of the switch). If you have a FSM or if some of the old links work you can find out how. I probably did a write up, hopefully I wrote the colors in the post instead of just posting a picture that is probably long gone now
#22
You might just have to replace that/those connector/s. Nissan usually sells them with like 6" leads. peel back the rest of the wiring harness, then cut and solder & shrink wrap.
I suggest replacing the TPS, IACV, and temp sensor connectors in your case...
My car won't idle for sheit now with AC on after I ported the heads. I think the engine just needs too much airflow that the IACV can't compensate enough. with AC off, it runs fine although it will dip a bit low when I first let off the gas. with the AC on, it'll just shut off every time I push the clutch in. CONSULT says the thing is working fine electrically.. so I think it's just a matter of not enough airflow. I guess I need to take it apart and drill out the openings a bit to increase the throughput of idle air....
I suggest replacing the TPS, IACV, and temp sensor connectors in your case...
My car won't idle for sheit now with AC on after I ported the heads. I think the engine just needs too much airflow that the IACV can't compensate enough. with AC off, it runs fine although it will dip a bit low when I first let off the gas. with the AC on, it'll just shut off every time I push the clutch in. CONSULT says the thing is working fine electrically.. so I think it's just a matter of not enough airflow. I guess I need to take it apart and drill out the openings a bit to increase the throughput of idle air....
It has been a long time since I've toyed with a VE IACV, I hope it isn't too challenging to machine.
#24
I tried cleaning the corrosion on the coolant sensor harness but finally gave up and replaced the harness in the manor you mentioned, about a month or two ago. The corrosion had gotten into the wires a good way down the harness. The TPS and IAC connectors all seem to be in good order and are clean. I would have replaced the coolant sensor too but it appeared to be working fine when I checked it. I still may do it on spec soon but it's been running well.
Funny the IACV might not be large enough for just ported heads. A friend of mine has a 2005 Corvette with a bored and stroked 6.8L LS3 V8, with L92 heads (intake ports are massive), high lift and duration cam, ported intake manifold, and it idles great once retuned. Comparing the stock engine to the 6.8L, the fuel table was bumping up to its maximum level it could adjust to under the stock tune, which is evidence that there is significant increase in airflow, but once retuned idled fine. Now that I think about it though it's a wireless throttle so I don't think it has a conventional IACV.
#25
#27
Hi, I was just directed to this site by someone on 240atlanta (where I stay at.) I was wondering if someone could post a picture of these wires that Im supposed to ground. Because I have no clue what you guys are talking about. Any help will be greatly appreciated.
Thanks, Andrew
Thanks, Andrew
#29
There's 2 wires that go to each solenoid, you ground 1 of each. I forget which colors though, I never did it to the VE's i've had. Someone who has will chime in, maybe with a pic.
#31
So the yellow/green wire goes to pin 113 on the ecu. Then their is no need to splice it from the engine bay. Simply cut at the ECU loom and either send it to ground or install a switch so you can toggle between ECU and ground. Got it.
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