Greeting, our 01 T206H had a G500/GTN750 with a EI MVP 50 engine monitor installed in 2013. It appears shortly after (according to data downloads) the owner was operating with a semi-faulty engine monitor for a decade or more.

Does anyone have a MVP 50 that has random fluctuations of engine data: ex cht, egt, oil temp, fuel level etc bouncing around with different values in no particular order= very random. We've cleaned almost all contacts, replaced two key probes and are now thinking the EDC (main computer) is the problem. Partner, A&P, is very electrically minded and has been using multimeter, mini multimeter, swapping probes/sensors and he is very meticulous with his work and downloads the data after every flight. So far nothing definitive; therefore, next step change $800 EDC.

Any ideas?

Sounds like you're on the right track to me, does EI concur? They should be able to bench test your existing unit and see if anything's going on there.

A&P partner has been talking to EI all along. I was hoping somebody had already been through this trial and error. Thanks for the response Halestorm.

We have a CGR30P rather than the MVP-50 but what I discovered regarding erratic readings was this. If erratic on multiple sensors, focus on the common ground side. Also applied in my old Jeep. I recommend a very close look at your alternator ground cable. Wiggle it and test for good connectivity. Mine kept loosening until I replaced the locknut.

We had one with the same issue on a (Insight engine monitor my Mistake thought they were EI), was the harness. It had about 6000 hours since install several engine replacements/overhauls.

An other one had a erratic display and that was the filter on the harness missing.

We also rerouted the harness away from other electronics/ignition leads.

That said I have run EI engine monitors in all our aircraft and particularly the later ones do not last very long , replaced at least 6 heads in the last 10 years.

My spare is a almost 20 year old first generation monitor it still works and our Maule has one of them as well that still works.

S Again that was with Insight not EI my mistake.

Some random advice for the MVP monitors. if you want to replace the internal battery. it's a $1.00 watch battery. I think they quoted me like 200$ a few years ago.

Thanks for all the good info. Cameron96, thank you especially for the PMs and research you did.
Jack

Cameron96; sorry, I responded to the wrong post even though I only have two currently. Meant the fork issue.