07 Phazer PZ50 won't start with right engine constants

[legomax]

My team's has been struggling to get our PZ50 to start. We feel something critical is wrong, as it won't even try to start with all the right engine constants.

Our constants include but are not limited to (on Megasquirt v2):

2 cylinder (sparks only A and B (or 1 and 3)) , 12 tooth (no missing), crank vr, cam hall, twin-parallel, COP, odd-fire, 180 crank offset (clear image in the phazer manual), alternating, 4 stroke

(The following were captured with timing light)
injection angle during cranking: 380
ignition angle during cranking: 33 (10 advance)

(The following were the least noisy combination captured with tooth logger)
ignition edge capture: Rising
cam edge capture: Falling

Disconnected sensors for "rough start:"
-O2
-map (only reads P-atm)
-TPS (can still open throttle with peddle, just no pot to ECU)
-Flex Fuel
-Fuel Pressure Regulation (only original with internal pressure sensitive gasket installed)


Been trying to start this engine for years, any help would be appreciated.

 

[MrSled]

Does it have compression? Did you do a leak down on it ?

 

[legomax]

Does it have compression? Did you do a leak down on it ?

Good call. I performed a crank test to use the composite logger and discovered no compression. There was compression several months ago when we started testing until the crankcase was opened via removing the sparks. I've recommended to the engine rebuild team to follow the University of Maine's 2013 Clean Snowmobile Team's: "50 steps to rebuild the engine" as they used a lot of liquid gasket to seal the chamber.

I also discovered via a YouTube video by Ian's Life on starting a Phazer that Yamaha poorly described the implementation of the oil lines in the manual. If wired backwards (inlet-inlet and outlet-outlet) versus (inlet-oulet x2) the engine won't start.

Sure enough, looking over my engine, I saw the backwards oil lines, which means we haven't been building oil pressure for years...


I haven't confirmed it yet but I think we also have low fuel pressure as we kept hearing a loud 'pop' from the fuel pressure regulator area.

 

[MrSled]

Could have stuck valves.

 

[legomax]

Could have stuck valves.

Hello, just an update.
The oil lines were assembled correctly the first time. It turns out the YouTube video I referred to was confused on oil line assembly and nomenclature. Upon disassembly of our oil lines, there was indication of used oil, which validated our concerns with the YouTuber's logic.

-Our main issue is we can't get compression. We've checked our cover gasket and confirmed it was installed correctly. Also, when the engine block was disassembled and cleaned 6 months ago, we were able to get compression on the first crank test. I asked for a crank test without seeing compression in TunerStudio, so the sparks were pulled and 0 compression was achieved and we've had 0 compression since. We're hesitant to check the status of the valves as the exhaust is still pushing out air and the intake is still creating suction, which imply some compression is taking place. We would appreciate any more thoughts.

Thanks.

 

[legomax]

Does it have compression? Did you do a leak down on it ?

We're going to acquire a leak down test kit to search for gaps

 

[legomax]

Could have stuck valves.

So after some fund acquisition delays, we've been able to acquire a leak-down test.

-Cylinder 2 had 90 psi on the intake, 87 psi out

-Cylinder 1 had 90 psi on the intake, 20 psi out on all strokes and tdc.

Stuck valve? (makes sense since, we only programmed the megasquirt to fire on cylinder 1)

 

[MrSled]

So after some fund acquisition delays, we've been able to acquire a leak-down test.

-Cylinder 2 had 90 psi on the intake, 87 psi out

-Cylinder 1 had 90 psi on the intake, 20 psi out on all strokes and tdc.

Stuck valve? (makes sense since, we only programmed the megasquirt to fire on cylinder 1)

Sounds like a stick valve or it’s not shimmed correctly and the valve is hanging open.

 

[legomax]

Sounds like a stick valve or it’s not shimmed correctly and the valve is hanging open

Disassembled the engine head and looked at the valves. All vales are seated properly. Then took out the valve block and tested filling the valves with liquid to see if any were leaking. No leaks. Then tested the valve springs, all compressed and returned to original position at spec forces.
-Any ideas?
-Again it was leaking on cylinder 1 on all strokes, think the piston o-rings broke down? or what about the cams not being seated properly?

 

[74Nitro]

So after some fund acquisition delays, we've been able to acquire a leak-down test.

-Cylinder 2 had 90 psi on the intake, 87 psi out

-Cylinder 1 had 90 psi on the intake, 20 psi out on all strokes and tdc.

Stuck valve? (makes sense since, we only programmed the megasquirt to fire on cylinder 1)

I don't understand the results of your leakdown test. Leakdown testers measure in percentage. Compression testers measure in PSI