Chapter 23 - Section 16

Engine Start


This is one of the most exciting moments of this journey is to push the start button and hoping to hear some loud noise coming from behind you. After years of building, my moment has arrived...


My initial understanding was that once I got the engine started, there would be just a short hop to the first flight. Well, not so fast... My first engine start moment arise without much fanfare. I just keep working at it from hanging the engine (again), flushing the fuel tanks (found very little debris), tie/clamp/secure all wiring in the engine compartment, tighten all the fuel & oil hoses, re-hang engine baffles, and double checking electronic connections (though not completed its programming). Doug Pitzer (my hanger mate) nudged me on beautiful Thursday afternoon (11/12/2015) ...quit fussing around, just DO IT...


I have an IO320 modified for 10:1 compression, delivering 185HP (per Performance Engines, La Vern, CA). I have Electronic Ignition (EI) on top and Slick Magneto on the bottom.


First Start

Since my engine has been sitting dormant for 3-4 years, we decided to pull all the spark plugs out, added 7 quarts of mineral oil (Phillips) and crank the engine several cycles, just to get the oil back up to the top side of the engine. It was exciting just to see my propeller spinning by the starter. I cleaned off the plugs with gasoline and torque them back in (20 ft-lbs).


Tom Kennedy from the other side of the Chino Airport came over ,with his giant size fire extinguisher in hand, to be my fire chief for this special occasion. Doug & I pushed my Cozy out of the hanger - with no wings, no canard, no canopy, no cowling & no IP cover - no fan fair. After receiving start up procedure / sequence from Doug, I pushed the start button...


No start with the first crank. The second crank produced some loud noise. Doug walked over and helped me with throttle and mixture controls to keep the engine running. The engine ran rough. We decided to shut it down and do a quick inspection.


Here's what we found:

- Slight fuel leak at #2 fuel injector;

- Quite a bit of oil leak;

- Cylinder # 4 is cold (i.e. not firing);

- Fuel pressure was reporting at 40-41 psi (too high)

- PFD and MFD both went out during start up;

- Oil pressure sensor is working appropriately.


Since it was getting dark and the engine was still hot, we decided to call it a day and do the repair the next day.


First Repair

The fuel leak was at the injector for Cylinder #2, which was easily fixed by tightening the fitting at the injector. I remembered I replaced this fuel line because I nixed it with my drill bit when I was installing my baffles.


After some looking and hand feeling, the oil leak was from the Vernatherm and Oil pressure sensor. A bit of checking and learning, I realized that they need to be torque as well. Actually, I only tightened them by hand. The torque values for the crush washers are 300 in-lbs (25 ft-lb) or 180 degree turn on the head of the vernatherm and sensor fitting. The spacing between the vernatherm and oil pressure sensors are so tight, I have to remove the oil pressure sensor and a couple oil hoses before I have adequate access room to tighten both sequentially to 25 ft-lbs. I further safety wired them to each other.


It was mystifying why cylinder #4 did not fire at all by both the electronic ignition AND the Slick Magneto. Our most likely scenario was plugged fuel line because it affects both. The fuel line from the spider to the fuel injector were removed and cleared. We further tested the fuel flow through the line by turning on the boost fuel pump while leaving one end of the fuel line open. We collected a fair amount of fuel in just a few seconds. We considered that was not the cause or to be fixed.


Second Start, Trouble Shoot and Corrective Actions

We pushed the plane out of the hanger and performed our second start. The engine started up after a few cranks, but still running rough...We decided to shut down and re-think. Cylinder #4 was not firing. We knew that because the cylinder cover (at the engine) remained cold (while others are getting hot) during the short run-up. Since my engine have been sitting dormant for several years, we decided to pull all the spark plugs out for examination.


The plugs (especially the lower ones) were oily and black. I cleaned them with gasoline and a soft tooth brush. After cleaning, I measured the resistance on both sets of spark plugs as follows:


Top plugs (Electronic Ignition)

In k Ohms: #1 (5.75); #2 (4.88); #3 (4.61) and #4 (7.71)

Bottom Plugs (Slick Magneto)

In k Ohms: #1 (.988); #2 (.993); #3 (.906) and #4 (1.08).


They all seems to be close in value, but decided to learned more about it in the web. A few links pointed out that plugs with higher resistance values may not fire consistently - but nothing specific (or quoting specific values), probably because there are so many different automotive and aircraft spark plugs in the market. All I can rely on is anomaly within my group of plugs.


Third Start

Doug pulled out his remote infrared heat sensor to monitor the cylinder and exhaust temperature. Without much more to go on, we made a third start. Unfortunately, the engine still ran rough. This time, both cylinder #3 & #4 were not firing (cold cylinder & exhaust). This was puzzling because it had to be both spark plugs not firing. That could be the coils for the Electronic Ignition or the coil wires. We decided to swap the EI coils and see if the problem follows the coils. In the process of removing the #3 & #4 coils, one of the wire from the EI controller to the coil slipped off its connector. That explains why both cylinders were not firing. Re-crimping the terminal was in order.


In addition, we swap both (EI and Magneto) #4 plugs with #3 and #2 with #1. We also replace one of the spark plug wires for EI cylinder#4 since its acted up from the first start.


Forth Start

Forth start still ran rough. However, # 3 cylinder was not firing. That's a good hint that my original #4 plug was bad (i.e. remember it has a higher measured resistance AND non-firing cylinder was following the "bad" spark plug. With that, I decided to change out all the EI spark plugs. Since they are the automotive types (NGK 3961 copper plugs) @$2.50 each from local auto store, I may as well get a good start. I also decided to change out the spark plug wires and plugs for the MAG. Dough happens to have a spare set, so I used his and the plugs are the massive type (P/N REM 37BY) @$29. each from Aircraft Spruce.


Fifth Start

With all the new installation, I started the engine (again). Engine started a bit rough but certainly not as bad. While Dough was confirming that all cylinders were firing (i.e. temperature from all cylinders and exhausts are heating up), I started to lean out the engine. All of a sudden, the engine ran smooth...I was wondering what Doug did, and he was wondering what I just did.


At this time, I turned all electronics on and documented various readings from the EFIS. It turned out that I have to do few more programming with the GRT EIS unit. They include:

- Engine Cylinder Number Setting (from 6 to 4), such that my Manifold Pressure will read correctly;

- Enter the Scale Factor (199) and Offset (68?) for Aux 3 (Manifold Pressure as identified on the GRT Manifold Pressure Box) );

- Enter the correct Scale Factor and Offset for the Princeton Fuel Probes.


All in all, it took me 5 trial runs with corrective actions to get the engine running smooth again. I am happy.


Back on programming with the Electronic Instrument!