Jump to content
SAU Community

Testing If Vct Is Working Properly

Chi100188

By Chi100188,
in Engines & Forced Induction

 Share

Recommended Posts

Chi100188 Mentor

Chi100188

Posted
  • Author
Posted

well last week i was getting car tuned had a few problems in the past such as cas,coil packs, exhaust cam gear set on 2 degrees retard all been fixed now and the car still wouldn't make any power down low until 5k rpm the power would just shoot up so the tuner reckon it was the VCT not work so i changed the solonoid but i want to test if the vct is really work or not

PM-R33 Grand Master

PM-R33

Posted
Posted (edited)

First thing do this:

1. Start car

2. Remove plug from VCT solenoid

3. Set up test light onto VCT solenoid plug

4. Get some one to put car into gear (obviously holding the clutch in) and rev the car

The test light should light up above the 1200ish rpm and stay lit until the 4500ish rpm. This will tell you that the ECU is actually giving power to the solenoid.

The only way now is to put it onto a dyno and do two runs back to back plotted on top of one another. One with the VCT plugged in, one with it unplugged. If both runs are identical you know you have a problem with the solenoid itself. It is pretty rare to have a solenoid fail though.

Edited by PM-R33
Messiah Mentor

Messiah

Posted
Posted

or poor mans seat of the pants approach.

Give it a bootful in low gear to 4k rpm with vct plugged, ensure you stay below the speed limit.

step 2.

Unplug vct and repeat, if run two feels like arse... vct is working ok in run one. if they feel the same... vct is broken

Kaido_RR Grand Master

Kaido_RR

Posted
Posted
what ecu are you using? may have to setup vct as an output.

Its running a PFC.

we have have heaps of issue with the car and has been to the tuners now 3times and still no complete tune, so the owner is getting abit dishearten hence why we want to work out if the VCT is working.

We did a swap yesterday using the old VCT solenoid from my old engine, however we are not 100% sure if the solenoid was the problem or if we needed to swap the cam gear aswell

RRob Community Regular

RRob

Posted
Posted
You should be able to hear the solenoid click when you pull the throttle when under the bonnet, this would suggest it is working... It's a noticeable noise

The car has to be in gear(just not in neutral) for this to work.

Chi100188 Mentor

Chi100188

Posted
  • Author
Posted

so i pretty much sit in the car put it in first clutch in rev it till 4000 rpm to and get another person to have his ear in the engine bay to hear a click or not or alternatively just drive the car with the vct plug in then take it out and see how the drive is after that?

  • 2 weeks later...
Rolls Grand Master

Rolls

Posted
Posted

Where is the VCT solenoid in the engine bay? Also when does it switch on, 1500 - 4000 rpm? or is it 5000 rpm.

Just got my eboost street and it has a window aux function which I am planning on using to control my VCT.

Also does the VCT activate when you ground the relay, or provide power to it?

Cheers

  • 1 year later...
urtwhistle Proficient

urtwhistle

Posted
Posted

Hey guys I'm wondering if I have potential problems with VCT on my R34 also.

I have tried testing it as well as I can until it goes on a dyno, so please give me your thoughts.

I removed the VCT plug and applied power directly to the solenoid and it clicked as it should have. I measured the voltage at the plug @ idle and it had 10v but I couldn't get it to trigger and go any higher.

I tried setting the power fc trigger points at 0 4500 and 7400rpm and 7400 gave the best boost response for some reason.

I also tried driving around with it plugged in and unplugged and there was no difference.

Rolls Grand Master

Rolls

Posted
Posted (edited)

You need to put it on a dyno and wire it on all the time, do a power run, then unplug it and do another dyno run.

Now overlay the two graphs, where the graph with it permanently on dips below the graph with it always off should be your ultimate switch over point. Doing anything other than this is guessing and will give sub optimal results.

53948234.jpg

edit it is possible the solenoid is jammed, I had to hit mine with a hammer and then pulse it on and off 10 times to get it to start clicking.

Edited by Rolls

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kinkstaah
      Nismo GT Pro LSD configurations

      By Kinkstaah · Posted

      I don't know if you can disassemble the thing and put it backwards for different ramp rates. They're both "2 ways" or both "1.5 ways" because well, 2 ways and 1.5 ways are the same 'thing' I do not know for sure, but I believe the 38420-RSS15-B5 is the 1 way, and 38420-RSS20-B5 is the two way. In other words, I predict Nissan considers this: to be a 1.5 way. No idea what actually happens when it arrives/you disassemble it. It would be an excellent question to ask Nismo directly! I somehow doubt you will get an answer though, I feel you would be the first person to document what you encounter when you open the box and the internet would be grateful.
    • Duncan
      Replacing Fuel Pressure Regulator

      By Duncan · Posted

      I'm going to slap an old nismo logo sticker on my spare one and sell it to the land of the free for a thousand bucks
    • Duncan
      Replacing Fuel Pressure Regulator

      By Duncan · Posted

      lol, probably should have read further!
    • R32 TT
      33 GTR Broken front wheel knuckle

      By R32 TT · Posted

      Well - they have arrived.  And they are easy on the eye to put it mildly... These only have three bolts - but for a start there is a key that fits with vacuum like precision..  And as you can see by my ruler, the interface is large..   I listened to a podcast on HP Academy about Dan (KiwiCNC) and I'm more than comfortable he knows what he is doing. R35 Bearing assembly should arrive later today so can mock that up for a look. Can't wait to get these on and get some brake pressure logging too. IMG_3860.MP4
    • GTSBoy
      Nismo GT Pro LSD configurations

      By GTSBoy · Posted

      I would be very confident that they are the same parts (the 2 different SKUs). It seems very clear that you can drop the cam in the 2-way opening, or in the other opening. If you arrange it in the other opening in the same way that you see any other 1-way diff, ie, with the flat of the cam up against the 1° side of the opening, then it would work as a 1-way. It can only spread the ramps when driving forwards - cannot spread the ramps on overrun. It would then appear obvious that if you put the cam into the opening "backwards", that you would get the angled flats of the cam working onto the "points" of the 1° side of the opening, which would give you ramp spread in both loading directions. I do wonder if the forward direction of the 1.5-way config is equivalent to the forward direction of the 2-way, seeing as the cams are flipped and the angled surfaces on those would need to be the same on each side - AND - clearly when installed in either the 2-way or 1-1ay configuration they are not intended to work exactly the same (the ramp angles on the 2-way are 10° different between forward and backward, and the ramp doesn't exist in the 1-way config). 'twere me, I think I would rather actually have a set of rings that offered the 2-way with two different sets of ramp angles, say the 55/45 of the existing design and maybe a 45/37.5 combo for a less aggressive effect), AND another set of rings with a dedicated 1.5-way opening and a dedicated 1-way opening. The 1.5-way opening would actually have the steeper angle on the overdrive side that causes it to be less pushy than the forward drive angle, like you see in many other diffs. But really - if this Nismo thing is thought out properly and all those surfaces work on each other the way that they need to, who am I to argue?
×
×
  • Create New...