Hi Guys
We got some further fault finding done today towards isolating the cause of the massive missing problem with our Renesis 4 port.
The troubling symptom / major problem is as we approach 23-24” MAP at various prop pitch and rpm’s (both A and B computers),
with very little warning begins to miss and then pretty much go immediately into massive missing and popping in the exhaust.
Just before the bad stuff begins the EGT’s read 1540 and 1440.
I have only done mode #3 programming and adjust the mixture with the manual mixture control while watching the narrowband.
It stages at 19”Hg as per Tracy’s recommendation for Red and Blue Injectors.

So order of events today:

I wondered previously what the seals where like so having received a new $22 pressure transducer I took out trailing plugs and
grabbed some pressure data while cranking.
See plots in WORD file attached -
Rotor #2 has one pulse down by max of 6 psi compared to the highest pulse. Does this mean that side seal is leaking?

We then went after 3 key possible problems:
1st being Engine monitors holding Injector #1 open so:-
A. Disconnected Dynon engine monitor to isolate it as a cause of disturbing Injector #1. No change.
B. Disconnected EM3 to isolate the same as above. No Change.

2nd being Pulses in the intake manifold messing with EC2 fueling.
We inserted a 0.6mm restriction in MAP sense line. (This line then ’t’s’ of too A and B Computer MAP’s. No Change.

3rd Renesis CAS generating to higher input voltage. Tracy recommends 1K across CAS’s.
I think this mod may have been done. See photo of EC2 PCB below pin 4 & 23 both tied back to pin 22 via something inside the heat shrink.

So I’m stumped for the moment.
At least we know more of what the problem isn’t, Which is helpful.

Also the EM3 does at times fail to read RPM etc and display reads NOP.

Appreciated any input.

Cheers

Steve Izett

Good work on the pressure recorder Steve. I guess you used a Micromite.

What brand of pressure sensor did you use?

Could be a side seal leaking as only one chamber seems to be affected.

Try changing your spark plug gaps to .020".

Check the gap on the inductive sensor on the e-shaft. The closer the better.
Make sure the bracket is stiff. You don't want it resonating at some RPM.

Are you still using the Chevy coils?


What most people do in road racing is put a container in the MAF plumbing to average
out the MAF. One has no idea exactly when this is sampled by Tracy's computer.
It tend to vary cyclically with RPM. Putting it another way it damps the manifold
pressure variations.

Here   is a picture of it on  a road race car.


Paul Lamar