Surplus VM1000 Parts

[Glas467]

Hi Folks,

If anyone needs parts for your Vision Microsystems VM1000 or EPI-800, please drop me a line.

[PensacolaPilot]

Originally Posted by Glas467

Hi Folks,

If anyone needs parts for your Vision Microsystems VM1000 or EPI-800, please drop me a line.

Reggie,
I have a Vision Microsystem VM 1000 in my RV 6-A. Works great but last week after refuelling I got a High fuel pressure reading. the sensor normally indicates 2 to 6 PSI (it seems to fluctuate randomly!!) but at start-up it flashed a 8 PSI reading. Resolved itself after a couple of minutes.
My question: what is a normal fuel pressure indication for a carburetor-equipped O-360?
Why does it warn me at 8 PSI? Is this something that the builder programmed in, or is there a real threshold?
Thanks.

[Glas467]

Couple of things to check here.

1) Connections at DPU and at the fuel press xducer. You probably have the older Hollingsworth type connector (4 blade connectors). These are susceptible to corrosion/dirt/grime getting on the blade connectors, often a quick scotchbrite cleaning of the blades and solvent clean of the receptacles will solve the problem. NEVER clean the transducer itself with solvent. Also check for snug connections at the DPU.

2) Check the tap line for the fuel pressure to the xducer. Air trapped in the line can cause high indications after shutdown due to thermal expansion. If air is in the line, check all fuel line connections for security.

3) Fuel pressure xducer reaching the end of service life. Often the xducers begin to get "flakey" after long time in service becoming less and less stable in pressure indication.

4) If you don't have a snubber fitting, you may try that. Carb fuel pumps put out a pulsed pressure profile that can cause fluctuations on the FP xducer. A snubber fitting will often smooth those out at the transducer. The snubber fitting screws on to the end of the xducer and into the tap line.

All the engine parameters are "hard burned" into the main program EPROM chip per mfr specifications unless it was a custom software for a special application. So whatever Lycoming's max fuel pressure is for your engine is what's programmed into the VM1000, if the pressure meets or exceeds this max, the VM1000 alarms.

[jim plaster]

I've got a MAP issue on my bird.....it's fluctuating from 5" to 21" at lower power settings....above 22" it appears fine. Fitting on sensor seems a bit loose...no leaks in other areas. Ideas?

[FasGlas]

Originally Posted by jim plaster

I've got a MAP issue on my bird.....it's fluctuating from 5" to 21" at lower power settings....above 22" it appears fine. Fitting on sensor seems a bit loose...no leaks in other areas. Ideas?

Clean the bronze filter in the MAP sensor. They are notorious for plugging up. There's nothing wrong with it. Oil mist clogs up the filter.

[jim plaster]

Heading up behind the panel next week to clean the filter and replace another component..no access from above ( yet) on this 6a...I'm giving my back another week to heal from the last trip under there...lol! Sure would be nice to be 15 years old and flexible again!

[Glas467]

Jim,
Were you able to resolve your MP flux issue?