01 GTX DI starts and dies instantly.

[AMINO]

I have a freshly rebuilt (low end) 951 gtx di that starts everytime for 1 stroke and then dies. I seems to stay running a couple more seconds with full throttle but not more than 2-3 seconds. I rode the ski on the lake after the reinstallation of the engine and it ran and idle fine in and out of the water. Even did a 20+ minute ride with it and then sudently a loud squeal and it died on me on the lake. I checked for spark and fuel and it seems good. Battery voltage is also good. I know there's some DI gurus out here that might know what to look for.
Thanks !

 

[tkarvelis]

Pull the plugs and see if you can spin the engine. If not, remove the pump. Try to spin the engine again by hand. Sounds like pump or engine seized.

 

[jhjesse]

Loud squeal doesn’t sound good. If it will turn over get some compression numbers.

 

[AMINO]

The engine is turning fine it really wants to start but it wont stay. Either by hand or with the starter. I got a compression tester ill get some numbers tomorow to see what they say.

 

[jhjesse]

Install the lanyard and listen for the fuel pump to turn on. If it doesn’t then you most likely have a bad fuel pump.

 

[AMINO]

The fuel pump turns on and pumps indeed fuel to the injectors (visually verified). Could it be sending too much fuel and flooding it?

 

[jhjesse]

Need a pressure gauge to find out. I would find out what the compression numbers are first then rig up a fuel pressure gauge and check fuel pressure.
Fuel pressure should be 107psi.
Compression numbers should be 130 to 140psi.

 

[AMINO]

Ok so i did a compression test and got a solid 90 on both cylinders.. but i dont see why it rode super well for almost 30min and pulled strong through the rpms.

 

[mikidymac]

I would get a second tester.

You are holding the throttle wide open before and during cranking with the plug wires grounded and a known good tester correct?

 

[AMINO]

I redid the compression test and now got 130 on both. But out of the water it idles and revs fine but under load in the water its running fine while on the throttle but as soon as i let go it will stall have eventually wont even start without full throttle.

 

[jhjesse]

Have you done anything with the fuel pump?
No maintenance lights correct?
I have experienced something similar to what you describe. Fuel pressure was within spec, but the fuel volume was restricted due to filters being partially blocked.
Just for process of elimination start the ski on the trailer with a volt meter connected to the battery and rev the engine while reading the volt meter. Should read over 13 volts but not more that 14.5 volts.

 

[AMINO]

Have you done anything with the fuel pump?
No maintenance lights correct?
I have experienced something similar to what you describe. Fuel pressure was within spec, but the fuel volume was restricted due to filters being partially blocked.
Just for process of elimination start the ski on the trailer with a volt meter connected to the battery and rev the engine while reading the volt meter. Should read over 13 volts but not more that 14.5 volts.

Now it simply wont start unless i give it almost full throttle and keep it immediatly over 4-5000 rpm and i can barely get it to stay running for a couple seconds. I replaced the sparkplugs since i found out that they were cracked and the plug caps too. Any thing else i should start looking up?

 

[jhjesse]

Loud squeal and quit....
I would remove the jet pump and see if it is locking up. While it is off try to start the engine. Process of elimination

 

[AMINO]

i did removed it and disconnected the shaft to try to start it 'freely' but still wont fire. It seems to start a little easier while spraying carb cleaner on the throttle body. But i tested both injectors (with a 12v) and they squirt right.

 

[jhjesse]

Check your fuel pressure. I am guessing it doesn’t have enough pressure to keep the engine running. Needs to be 107psi. Probably has just enough pressure to fire the engine but not to keep running.

Fuel pressure is paramount on a DI. It cannot vary more that one or two psi.