I’ve got the GRT EIS Model 4000 engine monitor on my C-90 powered 750. The past 12 to 18 months I’ve been getting eratic readings on OP showing anywhere from perfectly normal to spikes upwards of 99 psi. I bought a new VDO sending unit,and am experiencing similar, but not equal issues. I’ve never had a dedicated ground wire for it, so I experimented with grounding it out directly by attaching a ground wire from the hose connection at the sending unit to a good ground on the firewall. I am still getting erratic readings, sometimes perfectly fine, to sometimes off-the-charts wrong. I find it hard to understand that if the VDO Oil Pressure sending unit requires a ground, then why isn’t there a ground terminal built in to the unit? 
Has anyone else experienced similar issues and let me know how you dealt with it? 

Thanks - Jimmy Y

Views: 298

Reply to This

Replies to This Discussion

Not sure, Jimmy, but I think most VDO senders are screwed directly into the block so they are grounded and don't need a terminal - looks like yours is remote mounted, so it definitely needs a ground.

Erratic spikes and high spikes are signs the sender is wearing out.  I'll bet replacing it fixes your problem.  I highly recommend a solid-state sender such as the "Swift" sender that Spruce sells - it can't wear out!  However, it will require a power lead and an EFIS or gauge that you can calibrate.

John

N750A

I solved my problem with a direct grounding wire as shown. Used a hose clamp over the sending unit itself to secure the ground wire, then safety wired everything so it stays put. My oil pressure #’s are back to normal, here is a pic of what I did. 
I plan to make the Open Hangar event again this year, hope to see you there. 

I plan to make the Open Hangar event again this year, hope to see you there.

Yes, I'm planning on flying-in and will see you there!

Glad the ground fixed your problem.

John

Jimmy
I also have the same exact problem and didn't have the issue until 100+hrs, also I have GRT EIS.
I was going to ground with wire to side of sensor, but maybe a waste of time.
Vincent

Vincent,

That is exactly what I ended up doing, and it worked. I installed a hose clamp to the sending unit to secure the ground wire & ran that to a screw on my engine baffle. Oddly enough, mine worked for years without a dedicated ground wire, then began to get erratic readings off and on. Somehow for years it was grounding through the hose I am using.

By the way, I really like the looks of your 750 and followed your engine install and work done at FlyCorvair. I went to a couple of Corvair Colleges and learned a lot about them, but ended up with a Continental. Nice job!

RSS

New from Zenith:

Zenith Planes For Sale 
 

Classified listing for buying or selling your Zenith building or flying related stuff...


Custom Instrument Panels
for your Zenith
:

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.


Zenith Homecoming Tee:


Zenair Floats


Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz


Builder & Pilot Supplies:

Aircraft Insurance:

 
 

West Coast USA:

 
Pro Builder Assistance:

 

Transition training:

Lavion Aero

K&S Aviation Services

Aircraft Spruce & Specialty for all your building and pilot supplies!

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

© 2024   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service