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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?

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.

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

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....

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.

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

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...

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.