Ok guys, need to consult the brain trust. Friday I flew my 235 down to the beach. Mid-flight at 8500' I went to switch from one main tank to the other main, after switching I noticed the engine running rough and saw reduced fuel pressure on the gauge. The only fix I could find was to switch back to the tank I had been using. I tried several times even with the electric fuel pump running and every time I tried to use the other tank it would eventually start to drop fuel pressure.
I ended up diverting to refuel and on the group I checked all the sumps again, topped off the tanks, etc. I started the engine off the problem tank, taxiied, did my runup, etc - unable to reproduce the issue. To be safe I switched back to the good tank and took off, once I climbed above 3000' I tried switching over again and same thing! After 30 sec or so start to see a drop in fuel pressure.
Made it to our destination and they had an AP at the FBO, so I handed him the keys and described the problem. He called me later, he did the same thing I did and ran it hard on the ground on the problem tank and didn't see any issues. He said he ran it for a while.
Both theories I've got so far (trash in screen, trash/blockage at tank selector) should be reproducible on the ground.
Any thoughts?
I ended up diverting to refuel and on the group I checked all the sumps again, topped off the tanks, etc. I started the engine off the problem tank, taxiied, did my runup, etc - unable to reproduce the issue. To be safe I switched back to the good tank and took off, once I climbed above 3000' I tried switching over again and same thing! After 30 sec or so start to see a drop in fuel pressure.
Made it to our destination and they had an AP at the FBO, so I handed him the keys and described the problem. He called me later, he did the same thing I did and ran it hard on the ground on the problem tank and didn't see any issues. He said he ran it for a while.
Both theories I've got so far (trash in screen, trash/blockage at tank selector) should be reproducible on the ground.
Any thoughts?
