FX Problem after overheat

[Hydroburke]

Hi guys, new to the forum and am at my witts end. Yamaha fan and owner for many years, not too familiar with the 4-stroke sleds. I have a SRX 700 and I'm an aircraft mechanic by trade. I work on and build many hi-performance outboards.
A friend of mine bought a 2007 Phazer FX that had been overheated and just generally beat up. He brought it to me.
The wire harness was all pulled apart and the head gasket was blown. The cooling system pressurized after cranking it over. It did not run.
I pulled this machine apart, bought a wiring harness (used) and resurfaced the cylinder head .004" which brought it to true. (I have a machine shop)
I put it back together and it does not want to run, it has started several times but seems to die after a few minutes of running or if you touch the throttle. Then it will not start again.
Here's what I've done.....
-new gas
-new plugs (3 sets now)
-bypassed TORS (had a code)
-fuel pressure 45lbs
-compression 115lbs
-cam timing checked several times
-no codes come up
-went through all tests in the ECU, including verifying spark
-swapped in a different set of throttle bodies complete with injectors and pressure regulator
-all new to this machine (used Ebay) wiring sub-harnesses. All test OK with a meter.
-I pulled the oil pan off to check for debris, it was clean
-installed 2 new SPI coils
-increased the CO to full rich in 40 unit increments (because it doesn't accept throttle)

I do know for a fact that this engine has been turned backwards, the manual says not to, but not why.
It has the older style ECU but the wiring harness has the seperate ground.
Can the stator be bad and the ECU won't throw a code?
Can the ignition timing pickup be bad and the ECU not throw a code?
Can the ECU just be "bad" from the wiring being all torn apart? (there was 14 codes in the ECU when I got the machine)
Please give me some ideas!!
Thank you !!!!

 

[woolyviper]

did you check the coolant sensor? ecu relies on coolant temp for advance and fuel delivery on startup.
i'm not an expert but i like puzzles.

 

[cannondale27]

First guess:
Stuck fuel injectors.

Does it run when sprayed with starting fluid.Easy enough to do.

 

[Hydroburke]

I changed the harness to it and put in a new thermostat. I did not change the sensor itself.
I checked it with the ECU diagnostic and a infrared thermometer and it seemed close.
I will look into that, thanks !!
This "puzzle" is getting the better of me !! LOL

 

[Hydroburke]

Thanks cannondale, are they prone to stuck injectors? I swapped the throttle body and injectors once already and it didn't seem to make a difference.
I have it all torn apart again and will check with some starter fluid when I get it back together.
Thanks !!

 

[cannondale27]

No but I have seen it on other fuel injected motors.Either way it will give you a direction to look.If it runs on starting fluid you know your lacking fuel.

 

[cannondale27]

Another suggestion would be to hook up a Noid light to injector plugs to see if they are even getting a signal to open.All that cranking and you should have big time fouled plugs.

 

[Hydroburke]

I did do the ECU check for the injectors and they were "clicking" 5 times as they should.
Starting fluid sounds like a good idea, just have to put it back together.
Yes, I did have fouled plugs.
Are the SPI coils not as good as the stock Yamahas?
I'm getting another ECU too. That's one of the things that could make the ignition timing AND injector timing be out of phase.
Thanks !!

 

[porkchop]

Your friend better be buyin you a cold one or 12 after all this tinkering!

Good luck man

 

[greenthumb]

You seem to have covered your bases quite thouroughly.

First off, how good is the fuel? I would try some fresh stuff. You aren't by any chance using race or av gas? My turbo (lowered compression) behaves like this and can be a real PITA to cold start on 100ll.

It is quite common to overlook reinstalling the intake air pressure sensor hoses on the underside of the air box.
This would usually cause a no start, and usually codes as well.

When it does start, what is your idle speed?
You should be significantly higher than base idle on cold startup depending ambient air temperature. I usually see 2000-2400 depending on temp, it then comes back down after a minute or so. Maybe try turning it up a bit.

Make sure you keep the battery voltage up. They seem to be sensitive to this, and I assume youve been doing lots of cranking. I've seen some weird ecu behaviour on what you'd expect to be a good battery.

I had my FI apart last season, and it ran as you described afterwards. Thought I had installed something incorrectly or overlooked something. It just took much more cranking than one would expect after having it apart. It didn't start or run properly until I managed to get it out and do a couple WOT runs, and then it was fine.

Good luck!

 

[Hydroburke]

Greenthumb, yes, new fuel (although it's getting older and older as I go!! LOL)
Intake MAP sensors are attached.
Idle speed is 2200 (ish) on start-up, I've fiddled with the idle to try to get it to idle at 1800 after it comes down but it usually stalls before I can fine tune it..
I've had a battery charger on it as much as possible when it isn't running. What's your cranking RPM?I'm wondering about the starter too.
I'm going to see what the new ECU does before I tear into much more. I've never had a CDI or ECU go bad but I suppose it could be the problem.
By the way, i should've mentioned that the stator and trigger ohmed out OK and the valve clearances were good.
Thanks, keep the suggestions coming !!!!
This is very helpful in my thought process!!

 

[Mooseman]

Did you check the throttle position sensor? Manual does give an ohms reading it should have and adjustment.

 

[Hydroburke]

I didn't actually un-plug it and ohm it out but it degree'd out smoothly on the ECU diagnostics. I got 15 to 98 degrees if I recall correctly.......
The TPS was also swapped with the throttle bodies when I tried that too.
What kind of "last chance" filter is on the injectors? I haven't actually pulled them out and looked at them.
THANKS !!

 

[greenthumb]

I couldn't tell you a cranking speed off the top of my head, but they don't generally sound like they crank fast. Remember the clutch is turning slower than the actual crankshaft, so it is a little deceiving if you're watching it turn.

The '07's had a starter issue where the bolts holding the starter motor together loosened and caused the rotation to reverse! Remedy is loctite, but as I'm sure you're aware, the front end has to come off to get at it.

Do you have the yamaha service manual? I assume you do, but a .pdf version is floating around the interwebs if you don't.

So is it absolutely impossible to get it to rev up at all? No codes? Have you tried a squirt bottle of fuel? I'm scratching my head on this one.

 

[greenthumb]

Did you ever figure the root cause of the TORS?
Is it still over ridden and how did you do it?