Vario no vacuum from port A

[jtbo]

I have done most from these tests:
http://www.volvo300mania.com/forum-uk/v ... =6&t=12314

Electrical side is feeding 12V to A side coil, but no click or vacuum is present when I rise rpm above 1800rpm. All kickdown switches check out ok, no issues there either.

I did found out that previous owner had managed to swap A and B sides, so I put that right, also I did put repair kit into EMV, I did not replace diode as it seem to be working just fine when I measured it.

When I measure from wires there is clearly +12V when rpm is higher, but for some reason no vacuum from the port, no whistling sounds or clear clikcks.

Before I fixed A and B sides to correct way, I clearly found out audible vacuum when I used kick down switch, so coil should be working just fine.

Then I figure out that EMV passages must have been blocked, so I took EMV out, did blow gently to A port and notice air coming out from between electrick connectors, I did same to B side and result was same, that was interesting as I was excepting construction to be such that only outside air connector is connected to coil area?

I don't know now what should I test next, electrics are fine, so is underside as there is clearly pressure buildup and it also holds the pressure and lets it come out from hose too so there is only problem within EMV unit, problem that is either wrongly assembled, wrongly applied repair kit or some fault I have not yet able been to figure out.

Anyone have had such mystery fault with that EMV unit before?

Oh one thing came to mind, maybe it gets +12V but weak +12V, then again I have no idea how to measure that.

Also has anyone defineatly working EMV that they could ship here so that it would arrive in next two weeks? (all my cars are due to MOT next month and I try to get vario done for that).

[macplaxton]

I'll have a look upstairs later when I have a bit of time.

[jtbo]

I'll have a look upstairs later when I have a bit of time.

Thanks

I took whole unit out from car and indoors, must do bit of studying of how it should work, I guess solenoids move sealing 'piston' away from center piece when power is connected to solenoid?

Maybe it has no power to move it or something as fault replicates with another solenoid, can't think much of else really, I might play a bit with this unit and test with battery to see if there is movement and what effect it has, reverse engineering is fun

[macplaxton]

There is also the wax-sealed adjusting screw and glued on rear cap. But you shouldn't really need to go in there.

[jtbo]

At least there is one thing I have now found out, another small rubber seal at end of solenoid is not closing route of air from center hole as reliably as is the other one. One is in good condition original and another is one I replaced as old one was broken, must be that I did not push it hard enough so that it should of been installed bit deeper than what I did manage.

However I don't know if that would be reason for issue as when swapping parts around it should have caused different kind of results then. But I think that it still should make some vacuum to port, but maybe it is so small that one really can't notice that. So I need to buy some more gluing stuff and try to pray new piece off, preferrably intact and install it again but bit deeper. There was thicker part of shaft which rubber stopped and I did leave it there, but maybe I should of have pushed harder so that rubber would have gone over the thicker section, that is actually only way I think that it could make seal for center hole too.

[volvomania]

Sound to me that you didn't push the cup on far enough.
Normally when you push a BBB-made cup/piston on you feel the "pop" when it pops into position and you can "feel" the tip of the solenoid through the cup. The sleave of the cup slides about 2mm over the thicker bit of the solenoid.
Also you will see that the cup will sit in line with the rest of the solenoid, instead of "crooked".

[jtbo]

Sound to me that you didn't push the cup on far enough.
Normally when you push a BBB-made cup/piston on you feel the "pop" when it pops into position and you can "feel" the tip of the solenoid through the cup. The sleave of the cup slides about 2mm over the thicker bit of the solenoid.
Also you will see that the cup will sit in line with the rest of the solenoid, instead of "crooked".

That is very much correct, it seems I was bit afraid to use enough force.

But that was not only problem that there was, coil wires that come to connectors had failed, they made sometimes connection, sometimes not, also +12V feed to gear up side was not so good, connector came off by itself most of the time, I fixed, failed and fixed fails etc. I did fix 4 times those wires until I managed to assemble it into car without failing.

It is important to have connectors right way around relation to plastic part as there is sort of draft stop, umm, plastic pieces that stop connector to retreat when you install power leads, if those are at wrong position, then coil wires will fail, took me a while to get that, I think that originally it had only that cup fail and solenoids swapped, but now it works, it does everything as it should, yet still I could not see change in revolutions of wheels spinning on air or differences in sounds, but there is now clearly vacuum from port A and also at right moment too, maybe it needs a test drive now to see what rpm I'm getting at.

Maybe I can hook up diesel rpm gauge to 343's alternator for rpm reading as I have one at 240, still nearly 60cm of snow on top of it though...