oil pressure on prime

[Sonex374]

Engine on oil prime procedure indicated a climb from 1 then climbed up to 99 and held, have a grand Rapids eis and a vdo pressure unit from Sonex. Oil temp was shop temp around 60 degrees. Is this normal?

[Rynoth]

I recently did this and got an oil pressure around 75-80PSI. Initially I wasn't getting a good reading on my MGL efis and had to tweak some settings on the RDAC. I verified the pressure using a round dial gauge off my air compressor.

I'd verify your electrical oil pressure gauge with a mechanical gauge before calling it good. Just screw it into the same 1/8" npt hole the VDO gauge is in now. Should be able to find a cheap mechanical gauge at most hardware stores. Use a mirror or a buddy to watch the gauge while you crank the engine.

I will note that I almost took apart the oil pump to re-lube because it took a few tries to get everything to prime, some of the lithium grease had firmed up a bit (assembly was 8 months ago) and had to be pushed through the lines I think. It's easy to see if you're getting full circulation in the turbo aerovee by checking the line that dumps into the valve cover.

[Onex107]

99 is twice what it should be. You need a different setting or you have the wrong vdo.

[Heywoody]

I used the Sonex VDO along with the GRT EIS and flew for a year before realizing the GRT was looking for a 0-100 psi gauge whereas the Sonex unit was 0-80......in the EIS instructions, look up the specs on the VDO gauge they call out......turns out the 99 psi readings I was seeing was really more like 50 psi....so I'd double check that compatibility to get the correct readings....

[jwd3ca]

I have the same setup. So is is possible via GRT settings and/or scaling factor to use the Sonex-supplied sender? Or must I install a 0-100 psi sender? Thanks.

[Sonex374]

You need to use the one indicated on GRT's EIS wiring diagram. The correct number is VDO 360OO4. I Purchased from Jegs no charge for shipping. Unit is 0-150 psi

[jwd3ca]

Actually, Rutter, the GRT EIS diagram I'm looking at right now shows a choice of two senders: a 0-150 as well as a 0-80. Are you saying that you've been using the 0-150 with a GRT EIS 4000, and it is accurate? And that you have actually tried the 0-80 and it does not work correctly? Looking for facts here, not opinions...

[Sonex374]

JW
I'm using a 2002 eis which I used the 0-150 per my previous post. I cannot give either an opinion or fact what the 4000 series requires. I would contact Eric at GRT for support answer to that.