96SE5Spd

I installed my Intake yesterday and ran into a few problems but for the most part everything went well, that is the car still runs. Either way I tested the functioning of the RPM switch at 2k it opeded the acctuator, I went for a road test with it set at 5k and it didn't open. Soon after I realized I had the hoses backwards on the solenoid so the Vacuum canister could not build up vacuum. I fixed this problem and again tested it in while the car was running, infact I tested it numerous times at 2k and 5k while the car was parked and everytime it opened up, but when I drove it I didn't feel anything. To further prove that it was not opening when the car was moving I tied the butterfly's open and then ran the car, this showed a very noticable differance in performance and proved that the vacuum system isn't working correctly. I can't figure out what else to do, any help will be greatly appreciated.

Thanks

Ryan

Sprint

iTrader: (10)

what rpm switch you using?

96SE5Spd

Harlan

Sprint

iTrader: (10)

all the prior posts i have seen with this simular issue was related to the switch.. check prior posts from Dave B and Keven97SE

96SE5Spd

I would agree but I can park the car after a run leave it running and then rev the engine up and it will trip the solenoid, I'm not saying it isn't the switch but it doesn't seem to be the culprit. What about to long of a vacuum line running from the solenoid to the acctuator, with a longer line wouldn't it take longer for it to depressurize the line and the acctuator.

Sprint

iTrader: (10)

not sure.. but i could have sworn dave b said it would work when the car wasn't driving.. but when he got on the road it didn't.. but again.. i am not sure

Nealoc187

iTrader: (23)

Sounds to me like a vacuum problem and the reason it opens when you are not moving and just blip the throttle with your hand or whatever is because its getting the vacuum it needs from wherever you tapped into manifold vacuum, but at WOT there is no manifold vacuum, hence your problems. Where are you getting your vac source from?

Keven97SE

I agree with Nealoc187. If you aren't using a relay (just the rpm switch), and the switch does indeed operate at idle, then the cause is likely the vacuum setup. Make sure the check valve is located on the right line and facing the right direction...the check valve should be located on the line going from the engine to the vacuum canister, and it should be pointed to flow TOWARDS the vacuum canister (air flows from the engine TO the canister). Also, make sure your vacuum source at the engine is a good source.. I'm tapped into the vacuum line that runs to the fuel pressure regulator and it works fine.

If your switch is the problem, likely the switch will only work a couple times each run before it flakes out. Shutting off the power and restarting the car will make it work again, but only for another couple of times. You can easily check for this by setting the switchover rpm to 1500 or blipping the throttle several times to trigger the switch. If the switch stops working after a few actuations, the switch or electrical connection is the problem.

Hope this helps.

NastyNissan

Sorry to poke into the conversation here, but shouldn't the check valve direction point towards the engine? Charging a vacume canister means taking away air from the canister to create a negative pressure environment....correct? When the valve is open (car is off) the check valve should open to allow the canister to go back to atmospheric pressure? I'm new to this stuff (Maximas in general...not automotive in general) so I could very well be on the wrong track. As a side note...I'll be doing the VI manifold this next fall and have been trying to absorb as much info on the subject as possible...the only conclusion that I have come to so far is that they should color-code vacume lines from teh factory just like wires

Spence

96SE5Spd

As yall said it was a vacuum problem but not with the way I had it set up, or so i think. There was a leak at the solenoid causing the canister to lose vacume thus the intake not working while the car is at a higher RPM. But there still could be a leak or I could have a crappy vacuum sorce, I tapped into the Evap's vaccume line, let me know if that was a bad idea, that was just the easiest place for the T connector to fit. I'm kind of sketchy on whether it works or not, the car feels faster but I hear no really noticable differance intake sound when the VI should be activating and there is no kick (this is what I exspected for some reason) so if either of these things should be happening let me know so I can do somemore work on the car.

Thanks for the tech support

Ryan

96SE5Spd

no even if the car is off the cannister should hold vacuum.

NastyNissan

I thought the point of the powered check valve was to open the canister when the engine was shut down...this is why I'm still the perverbial "newbie"...

Spence

96SE5Spd

I'm not flaming but air flows from the cannister to the engine, thats what creates the vacuum. I'm sure you knew this but just got your wording wrong.

96SE5Spd

The check valve prevents the canister from loosing vacuum when the car isn't creating any.

Dave B

All the canister does is store vaccum. When the MAP switch is activated, the vaccum of the canister is applies to the actuator and the butterflies are opened. When voltage is turned off to the MAP switch, the vacuum source is shutdown and the MAP vents to the atmosphere which ends allowing the actuator to close and the butterflys close.

The vacuum canister should store vacuum when the car is on or off. The reason for the canister is because when the car is at WOT, no vacuum is being generated. This is why a direct connection from the vacuum line of the engine to the MAP would be useless at WOT because no vacuum would be there to tug the actuator open. The canister stores engine vacuum much like sucking on a bottle and then letting you lip cover the opening and storing the vacuum. This is also why there needs to be a check valve in the canister or in-line between the canister and engine so that the lack of vacuum at WOT doesn't pull the stored vacuum from the canister back into the engine.

With the car off, you should be able to hear a loud hiss when you yank the line off from the MAP to the vacuum cansiter. If you don't, it's not hooked up right.

I'm pulling vacuum from the fuel regulator hose. It works fine.

I had problems with the Harlan switch only because I had it wired through a relay. Once I removed the relay, the switch has been absolutely perfect. No relay = perfect running RPM switch.

You should be able to hear the switchover if it's set at 5000rpms because 5000rpms is too low of a switchover therefore you'll hear the change in intake resonance. It should sound similiar to a stock B16 Civic SI on the switchover. You won't feel a "kick" though. If you change the switchover to around 5300, the switchover sound isn't near as audible because it's closer to the right point. Try 4500rpms and see if you can hear it. I know that when I had mine set at 4800, it was pretty loud.


Dave

NastyNissan

Ah HA! So the MAP goes between the canister and the intake, not the canister and the vacume source. I had it pictured in my head backwards. It is all clear to be now. Thanks! Wouldn't it be just as easy to lose the vacume source all together and install an electric solenoid actuator to work off of the RPM switch and rotate the butterflies? It just seems like an easier solution to the problem...

Spence

Nealoc187

iTrader: (23)

If you are not completely sure if your MEVI is working while at WOT, check it by setting the switchover to either 4000rpm or 6200RPM (approx). At these RPMs you should be able to easily tell if its working, if you choose 4000RPM you will feel a significant torque loss when the MEVI opens, and if you set it at like 6200, you will feel a surge like a small hit of nitrous as it opens, since at 6200 without it open you will probably be making only 150whp, and then when it kicks open you will jump up to ~185whp. Do this repeatedly to see if you feel the 'surge' or loss of torque. I can't hear my VI open, though some people with different intake setups can.

If you could find a solenoid that's reliable enough and strong enough to open the MEVI, but you'd be surprised at the amount of force it takes to yank the thing open. Nissan (and other car manufacturers) run variable intakes off RPM switched vacuum sources with vac canisters built in, so its probably the most reliable way they found to do it.

96SE5Spd

Thanks for the input guys, I'll tinker with it some tommorrow and make sure it is working. I was driving it earlier and noticed how easily I hit 70 in second,(I usually get out of 2nd at around 65) so I think it is working. But I'm going to do the things you said just to make sure before I close things up on this project. Thanks again for the tech support.

Ryan

BriGuyMax

iTrader: (1)

I had the EXACT same problem with my MEVI set-up and mine was the same as yours. I'm getting rid of the car so I never got a chance to figure out just what the problem was, but I eliminated a lot of things. The RPM switch is NOT the problem. The vacuum canister is NOT the problem, the lenght of the vacuum is also not the problem. That leaves me with only one thing. The tap of the vacuum line off the EVAP system. I was going to change it to the FPR hose but I got a new car.

BTW - You will know when the MEVI is working...it sounds different and feels different.

96SE5Spd

The only thing is when I tied mine open it didn't sound that much different except there wasn't much intake rasp at 6500, it was a little deeper but not enough to make it sound like a honda hitting Vtec, I don't know it feels faster but I could just be imagining things. I'll find out today though.

96SE5Spd

I did as Nealoc said and set the switchover point to around 6200 RPM. I didn't notice that much of a kick but the change in the pitch of the intake was evident. So unless I'm imagining things it works.

Thanks
Ryan

iregula

again, nissan engineers are not dumb, modifications at this level is risky

BriGuyMax

iTrader: (1)

what are you talking about?

Bags

iTrader: (3)

risky as compared to what????

changing your bulbs?

ok then what about a 5 spd swap?

turbo?

Supercharger?

VB mod?

and the list goes on... I am wondering exactly what you mean by your above statement

Dave B

Risky? This is a Nissan OEM part


Dave

96SE5Spd

No kidding what was dude thinking, its not like I'm messing with the compression.