I fixed the pressure /boost sensor

[crazyyamaha]

First off since this is my first post hi to everyone. I just bought a 1986 venture and this sight has been great.I fixed my solder joints on the CLASS very helpfull .Now onto how to fix the pressure / boost sensor for timing advance, if your sensor leaks vacuum. this is what you do.Remove sensor heat up a razor blade till it glows red with a torch carefully melt the top cover off by the seam this is opposite the vacuum hose plug .Remove cover what you will see is a bunch of jelly it looks like snot and feels the same way on the same side of the vacuum hose plug you will see a little black box it will have came unglued from the base there is four very small wires coming out of it hidden inside the jelly be carefull not to break them,carefully remove the jelly around the box and wires .I know its a pain but these things are like $300.00 and I have more time than money. Carefully lift up little box clean the bottom of it and the bottom of the sensor housing mix up some epoxy apply a small amount to the bottom of the box all the way around DO NOT GET ANY IN THE HOLE. Gently position over the vacuum hole nipple and wait for epoxy to set up. when set up you should be able to suck on vacuum nipple and it should hold vacuum .If all is good apply RTV sealent were you removed jelly stuff .DO NOT GET ANY ON THE TOP OF THE LITTLE BOX YOU JUST GLUED DOWN THERE IS A LITTLE HOLE THAT HAS TO BREATHE. Epoxy cover back on and check with volt meter IF you plug the harness conector in with key on you should have 12 volts on one terminal 2volts on the output terminal and that one will very if you suck on the vacuum nipple. If you by chance broke one or more of those tiny wires they can be solderd back on but it is not fun I know. Sombody on this sight asked if a GM map sensor would work instead .A gm map sensor works on a 5volt referance signal this work on a 12volt signal after checking both sensor resistances they are not the same.maybe with some resistors you might be able to get the GM sensor to work but that is a little out of my league .HOPE THIS HELPS.

[Freebird]

Very good post. Thanks for telling us how you repaired it. Many have had problems with the sensor and they ARE too expensive. You may have just saved somebody a lot of money.

[DonB]

Crazyyamaha

 

Yes I found information on the GM pinouts and I did apply 5 volts to the sensor and the output is 4.5 volts which would be too high for the TCI. Otherwise it works just like the 1G sensor. I'm going to try 3 volts into the GM sensor and this may work. Just haven't gotten around to it.

I'll report on my findings later.

 

db