Well guys i just got dynoed and you know i never realized my mevi isnt opening. Here is the situation

1. If i ease onto throttle and got WOT(100%) the mevi opens. If i lift the throttle to shift and go 100% throttle it will NOT open, untill i let off the throttle where it opens the closes quickly.

2. If i just go WOT without easing into it the mevi does not open it stays closed untill i let off the throttle where it flicks open then closes right away.

I have the nissan oem vacuum canister, i also had a napa swapped the napa for the nissan one and still does it. I have the Dawes control solenoid hooked up correctly im pretty sure. and i am using a summit RPM switch.

I really dont know what it is, its not the RPM switch, because it does open, just not if you slam the pedal to the floor, the control solenoid could be the problem but im not too sure, i dont want to start throwing parts at it, the vacuum canister isnt the problem either so im at a loss.

The Vacuum is being t'd off of the fuel pressure regulator.

Any help would be awesome guys, its really starting to bug me now, im glad i didnt do the 00vi swap, because i cant even imagine all the problems id run into..nothing for me is ever simply a bolt on!

 

IIRC teeing off the FPR has cause problems for MEVI owners before...Either try tee off of the small hose that hooks up to the intake or I was lucky enough to have an open port on my vacuum tree....try searching for an open one first....if not then tee off that other hose...I did that and it worked fine...

 

Alright ill try tee it off somewhere else. Thanks again mazzivart. Did you ever dyno? If so what did you pull>?

 

Nope I havent ever dynoed....I sold the JWT, which seems that USPS has lost, to a fellow orger....I am not sure what I am going to do now....I really love this car but I am itching to move on to something different.... plus my damn axels are going too...

 

Hmm that didnt work. I t'eed off a different port on the throttle body. No change there. Any other suggestions?

 

Okay this may be a stupid question butt here it goes. IF the vacuum canister has a built in check valve you should not be able to suck through one port correct? Well i can suck through both still, one seems a bit harder to suck through then the other, but if the check valve is operating correctly, i shouldnt be able to suck through at all correct? I wonder if that is my problem. the vacuum canister i ordered from work is 22372-V6700. It is off the VE30DE/VG30DETT/VG30D maxima/300zx. Has anyone used this one before?

 

do you have an inline check valve?

 

Does it have a rounder end with 2 valves on top one being white?

 

I think a search would bring up multiple threads. In fact Nealoc187 made a really good thread about it that included pictures.
My mevi wasn't opening (dyno proven) and then I got the check valve and it was like night and day difference...

 

Hmm, yeah it does have a round white circle in it. I did search, but its hard to read more then 1pg because none of the links correspond to the proper thread. I have to clicked the cached button and the information on there is usually old.

Perhaps i will try a check valve, hopefully that will cure the problem!

 

Sounds like you have the Nissan vac cannister with a built in check valve....how is the vac solenoid set up?

 

of out curiousity, which thread(s)/information did you follow during the install?

 

I wasnt asking for my knowledge I was asking so I can know what type of cannister he had...I have a MEVI and have for a couple months....

 

Yeah this sucks. I am sure the vacuum canister i bought had the built in check valve. I am going to see if i can find one down stairs in the basement, i really wish things would be as easy as they should be for me...but thats life.

Perhaps ill try a check valve again, if not maybe ill try the wreckors and pick up the check valve + control solenoid and vacuum canister all in one. That way i have a few extra parts to play with. Just gotta find a maxima in the wreckors now lol..

 

Have you checked all the wiring on the RPM switch...how did you set up the tachometer wire? is it on the screw on the back of the gauge cluster or tapped the tach wire? also are you sure that it isnt shorting somewhere.....are all the wires secured on the actual switch...

 

and how is the vac solenoid set up????

 

hmm.. thats bizarre. I used to tap my vacuum off the small one of the two sources but found it didnt have quite enough grunt to open the mevi fast enough - it would open slowly whereas when I used the larger one for the FPR it seemed to open quite quickly. Though, I never used a "T" adapter on mine. I actually had a three way cannister.

But i've always had one question.. if the vacuum is tapped from the manifold and the throttle is closed of course theres vacuum there. But if the throttle is at WOT then wheres the vacuum? Does it escape out of the cannister?

 

The tach wire is being tapped off the ECU, i chose that way because i had already tapped it for my SAFC2, admittently the wire i used was not very good, i didnt have a piece long enough so i attatched 2 pieces together. Could that be causing it? I could understand if the rpm switch wasnt even activating but it does, i have watched the green light come on.

The control solenoid is wired up the following way:

For those of you using the dawes, the port that has the metal teeth i guess to hold the vacuum line in, the output from the vacuum canister goes to that port. the port right beside it goes to the mevi, the port on the back is left open for a breather.

I have the positive on the control solenoid directly to the battery, and the negative on the control solenoid is attatched to the yellow activation wire from the rpm switch.

That is correct right?

Personally i dont think it is an electrical issue, just because of how it reacts, like part throttle then easing into WOT(past engagement point) it opens, but if i just go WOT at any time without easing into it, it does not open even past the engagement point. But the screwed up thing is, say you go WOT in 2nd, it wont open, then once you let off the throttle assuming you are past the engagement point it quickly opens then closes right away.

 

My guess is you have to have some sort of a vacuum problem.....you said that you didnt have an open port on your vacuum tree? the vac solenoid is set up right.....try teeing off every vacuum port and see which one is the best....I must be lucky for having an open port...

 

Yeah maybe ill try T off the brake booster. that for sure should give me good vacuum. Thanks again for all the help guys, really wish i could get this working, top end is really fun now, but its like driving a honda now

 

I think my problems will be solved with a check valve but im not sure if this makes sense. Basically what im thinking is:

Under part throttle and non WOT there is still manifold vacuum right? But once you got WOT the vacuum dissapears, i guess why it still works under part throttle is because there is still vacuum in the manifold, so instead of the vac can holding the vacuum it just sucks it through the vacuum which explains why it opens so slow. Now under WOT, there is little to no vacuum(i think?), which explains why it doesnt open and when the throttle is realeased from WOT it opens.

Basically im triyng to remember back to my auto classes, manifold vacuum is created by the difference in atmospheric pressure and the intkae manifolds pressure, well at part throttle or idle the throttle plate isnt fully open so there should still be a difference in intake manifold pressure and atmospheric pressure, at WOT there theoretically should be no intake manifold pressure becuase the throttle plate it open there fore the intake manifold pressure would be the whatever the atmospheric pressure is.

Did any of the above make sense?

It would all make sense, the thing im not sure about is the manifold vacuum being present at WOT. my check valve should be here tomorrow so i guess that will be the big test. Ill keep t'eed off my current port (right behind the TB) so i hope this works.

 

k so i got a 1 way cehck valve and that didnt help at all. tried a diff port to no avail.

im at my wits end, im at the point now where im sick of all the little issues involved with modding a car, if i cant figure this out im done with the car and ill probably end up getting rid of it sad to give up but you guys dont even know how much it is bugging me lol.

 

nah don't do that, i always enjoy reading your battle threads

 

calm down man I know exactly how you feel. This car can drive you freakin nuts if you let it.

Isn't there a way to check the vacuum by taking one of the hoses off of the canister and feeling the nipple for vacuum after driving the car for a few minutes?
I used to do it when I was diagnosing my MEVI.


Here's another option: Take the damn thing off. Just run the car with the USIM. When I was parting out my car I took off the MEVI and honestly the USIM + Upgraded ECU is alot of fun. (lots of lowend torque) I mean if your MEVI has never worked then.....you would actually have a faster car with it off!

 

im still curious...

 

I followed the write up on vqpower.com.

I am going to give some things a try tomorrow after work, theres no way im putting the usim back on, too much trouble, the top end is so much fun but right now its either a huge compromise of low-mid end or no top end. I was really hoping someone on here would have had the same problem and could have guided me in the right direction but i guess i gotta figure this out on my own.

I know i have vacuum, i tested it.

I took off the line running to the mevi actuator, and put my figner over it, at idle there was nothing which is correct, at 5000rpm i could feel vacuum. Now what i cant tell you is if i felt vacuum at WOT past 5000rpm. I think the problem could be the control solenoid, perhaps i will try re-wire it up to see if that helps or try a different control solenoid all together.

And thanks it means a lot to me 2pb. I actually had another one today, my freinds altima 2.5 auto again, just came back from seeing 30 days of nights and we went, the roads were cold so 1st gear was a show off wheel hop and spin but i still pulled a good 1.5-2 cars on him by 60mph. His mods are: intake, udp, headers, custom SER catback(2.5" to dual 2.25" to SER mufflers, grounding kit, system adds probably 150lbs. we both had 1 passenger.

 

Have you tried to tie the vacuum directly to the actuator? maybe you have a sticky and/or defective one....It could be losing vacuum thus not activating the MEVI correctly? Dude you really need to get this figured out....


On a side note the MEVI with my 95 ECU is pretty good too....just no 7200

 

Yeah im going to try that. SNOMAX who owned it before never had any problems, my only question is perhaps it was damaged during shipping. I really dont know but i guess ill find out. Ill test it that way right now. Hopefully its nothing major or else this is going to freakin suck

 

Alright here is the down low. its going to be long, but im trying to give you guys all the details in hope you can help me figure this out, if you can there may be a reward for you

Manifold vacuum at warm idle (approx 800rpm) is 19in.hg, which falls within specs, vacuum after vacuum canister, 22in.hg. Weird but nevertheless atleast the vac can is doing its job.

First, i ran a vacuum line from a port on the intake manifold right to the mevi actuator, it opened right away and opened fully, good, but once you start bring the rpms past idle..or maybe 2000rpm it closes i guess because it looses its vacuum, hence where the vacuum canister comes into play.

second, i ran a line straight from the IM to the vacuum canister, i didnt T off anything, still same results. Here is where it gets interesting, i set my rpm switch as low as it would go..which engaged it at about 4000rpm..when that happens if i slowly rev it to lets say 4200rpm the mevi opens..slowly albiet but it does open, now if i hold it at 4200rpm it stays open, but if i rev it fast or go full throttle while still holding it at 4200rpm the actuator closes, and then once i let off the throttle it quickly opens then closes.

So heres the issue, why is that happening, do i have something hooked up backwards? What would cause that? i will take pictures of the setup and post them and see if maybe idid hook something up backwards..if i did damn im going to feel like an idiot, but sometimes you gotta learn the slow hard way haha.

again thanks for all the help guys!!!

 

do you have the Delco Remy? im just trying to get an idea of the parts that you have and the parts that i have so that i can tell you how mine is set-up.

 

ok, you do have the Delco remy, i saw it in the other thread...

looking at the top of it, theres two ports on the bottom and one on the top. Leave the top one open, the actuator goes to the port on the left, the one on the right goes to the vacuum canister. My cannister is the big globe looking thing, not sure of the part number, but the port on the right goes to the smaller port on the vacuum canister. not sure which one you have, so im searching right now to find a pic of yours.

 

Maybe you should find someone else that is running the Dawe's solenoid and ask them how they had it set up?

 

Alright here are some pics.

 

Hopefully its something stupid like a line switched around or even the control solenoid.

I did notice that there is already a control solenoid on the maxima. I am wondering what it is for though. the OEM one from a J30 maxima (89-94) my cost is like 27$ and theres no stock in canada which means i wouldnt have it for atleast 10 days to 2 weeks.

 

read my post...your hoses are backwards on the solenoid....unless they can be installed vice-versa??

 

hmmm damn..i really hope that is the problem..at the same time its going to kinda **** me off if it is, such a simple problem lol.

Thanks alot man!!! I really appreciate the help, i really hope this is the end of it!

 

i take it this has been solved??

Makes me want to go out and check mine. I know it activates, but not sure if it does at WOT - never tested it..

 

Ok..I think your problem is that your solenoid may be to far away from the actuator...On mine I have solenoid about 3 inches away from it...Try moving it really close and see what happens...

 

Hmm maybe thats it. I will try that, i was suspicious of that, but i figured maybe it was okay. Ill try that and hopefuly that fixes it. i Tried swapping the lines, it does open faster now, but still not at WOT.

 

Im thinking that the vacuum is being reduced on the way from the solenoid to the actuator and/or arriving erratically thus causing your issues...