ok guys...I'm getting REALLY frusturated with my VI....sometimes it works...and sometimes it doesn't. I checked the Vaccuum canister, and it still has vaccuum left even after the car has been sitting for a half hour...so it's not that. The RPM switch lights up EVERY TIME I hit the set RPMs...so I'm pretty sure its not that.

Thing is, the VI will open no problem without a hitch when I set the RPM switch to 2000 and slowly rev the car over 2K. When I set it up where it should be...and slowly rev..sometimes it opens, sometimes it doesn't and sometimes it opens for a split second right when I let off the gas after revving over the switchover point.

This leads me to one thing...it HAS to be a vaccum problem of some sort. I tapped into the EVAP canister vaccuum source for my vac and T'd off of that. How do I go about testing the source????

 

From my discussions with Keven the EVAP isn't a constant vacuum source. Try tapping at the fuel pressure regulator instead. My VI has failed to have any problems with either the vacuum or Harlans.
-hype

 

Just curious how do you know it is NOT working? Butt dyno?


what size hoses are you using?

I found that sometimes the 3/16 hose would leak around fittings, even when using zip ties... I went to the next size down.. I think it is 1/8


are your sure you cannister is working 100%.. the check valve in my cannister failed on the 2nd day

I have had zero problems in the past 2 months

 

ok guys...update...I was so fed up I went to the local auto parts store and bought a vacuum tester. hooked it up between the Tee at the EVAP and the vacuum canister. at idle it's at 21 inches...perfect...as I get on the gas...it drops...no problems there.

So I hook it up between the canister and the Map/Baro switch...turn on the car...and to get vacuum and turn it off. The needle rests at about 19 inches and stays there for 5 minutes.

I then started the car up revved it a few times up to the activation point....sometimes it activated and sometimes it didn't. Every time the vacuum between the canister and map switch dropped (which I'm pretty sure it's not supposed to do unless the VI actuates. I then shut off the engine....and the vacuum needle started slowly dropping...interesting. It didn't do this before!?!? It slowly dropped all the way to zero. I did the same thing again....dropped again.

This pretty much explains my intermitant VI fuction problem. The vacuum canister only stores vacuum part of the time...the rest of the time it bleeds it off.

As for using the EVAP as a vacuum source...I see no reason why it would work. it's tapped DIRECTLY off the manifold and then Tees to the canister and the EVAP....that's about as constant a source of vacuum as I can think of.

Thanks for the suggestions guys...and Bags...I don't think I trust these napa canisters...

BTW - I could tell the VI wasn't working right while driving because I didn't HEAR the switchover. Sometimes it would finally kick in at 6300-6400 rpms...and at that point since there is such a power difference between open and closed...it almost feels like a 50-shot of nitrous.

 

Well, at least you found the problem... you are leaking somewhere from the check valve to the solenoid. I think you are probably right to question the NAPA. Although mine was working fine, I did put an additional check valve ahead of it just to have back up protection against check valve incompetance.

 

Good to know you got it fixed.. I got a new cannister AND put a check valve in line with it.. so I am covered times 2


I can feel when it is not working.. with my CAI and exhaust I can not hear the switchover.

But good to know it is working all the time now

 

Mismosh -

I tried installing a second back-up check valve...and the same thing happened Maybe I installed the check valve wrong??? I put it between the vac source and the canister and had the side that say's "vac" facing toward the vacuum source...I believe it's the side that you CAN'T blow into.

Any recommendations for a RELIABLE vacuum canister???

 

I say stick with the nappa

here are some pics I just took of mine..maybe they will help.. or maybe they will confuse you.. but you will kinda see what I did

 

see if this works pic 2

 

Here's my check valve and my F from the FPR.
http://www.vanillaice.com/webmasters...e/IMG_0302.jpg

If you go to a junkyard you can use the vacuum canister off of a 3rd gen VE (they had VIs too). The canister even comes on a bracket that fits on our drivers side strut mount.
http://www.vanillaice.com/webmasters...e/IMG_0298.jpg
-hype

 

If you are getting a slow leak, it is possible you have a crack in the canister. A check valve installed the wrong way will make vacuum storage in the canister impossible so I don't think that is the case... you are getting some, just not sustained. Also make sure your hose are not too big for the connectors. The NAPA also has one nipple that is just too small for 3/16" and should really be fitted with 1/8". BTW, the small nipple goes to your solenoid right? Check the canister for cracks, especially the port end. You can even test out the nipple by connecting hoses to it, sucking on one end and guaging the other. Vacuum should hold stable.

 

it's all hooked up right.....and my hoses are VERY small...I had a hard time getting some on them onto connectors...so that's not a problem. I'm going to take the canister back to napa tomorrow. thanks for all the help guys.

I still haven't gotten any feedback on tapping from the EVAP's vac source...good...bad??? Nealoc187 has his hooked up exactly like mine...and he hasn't had any problems to speak of.

 

I would get a long hose for the vacuum tester and connect it right to the electrinically controlled vacuum switch for the VI and run the hose into the car's interior (leave the hood open but latched (like you just pulled the hood release) and leave the driver's window open.

Use a hand-operated vacuum pump to apply vacuum to the VI, then hit your targeted open speed (5500rpm?)

You may need to use the vacuum pump again to keep it at 21 inches.

If you get reliable VI operation under these conditions then it's your vacuum system that is at fault. If it still doesn't work then I would suspect either the vacuum valve or the butterflies are stiff to operate or the actuator may be bad. Is there a return spring on the butterfly rod? Can you reduce the return force for testing?

You can repeat the test hooked directly to the vi so that you manually open the VI with the vacuum pump and thereby eleminate the valve from the testing.

The actuator should hold vacuum when it it activated. With you vacuum guage apply 21inches directly to the VI - it should open and stay open. Set the tester down and go for a cop of coffee. When you get back if you see 20/21 inches then it's good. 15+ it's ok-ish, less than 15 the actuator is prolly bad.

 

I use the EVAP for my vaccum source and everything has worked fine. I've had my VI installed for almost 6 months now without any problems. I'm using a "T" connecter off of the evap hose and I also use the screw type hose clamps at every connection.

 

Damn, I can hear mine plain as day on the switchover even with a modified stock airbox. Is your exhaust that loud Usually it's the intake that's really loud at WOT and that's when you really can hear the switchover.

My setup:
NAPA vacumm canister
secondary check valve (just in case)
RPM switch wired to MAP with NO relay
vacuum line to fuel regulator
minimal amounts of vacuum line used

= no problems (once I got the RPM switch problems figured out)


Dave