Engine surging?

[mvoellinger]

Yes I know I have a line over my rail and my speedo doesn't work, this was a quick run to videotape this issue. I touched the throttle right at the beginning then didn't after. Engine has 25 hours on a new longblock...mechanic wants to do the fuel pump. Any thoughts?

http://youtu.be/Z-Ul5JmI7X4

 

[dan313]

Have your mechanic check the motor with the lap top. Just to be sure its not something other than the fuel pump.

Lenny

 

[sdleo26]

That's exactly what my motor was doing , changed high pressure pump and back to normal

 

[Chris Nowell]

Can he test the pressure before he starts replacing parts. The hit an' miss method will fix the problem eventually (maybe) but I think it's better to diagnose the problem rather than throwing parts at it. There are fuel pressure test kits available to test these high pressure pumps. Most of the marine shops that I know of have them in their tool cribs.

 

[Bop]

I had the same issue. Loose wiring harness to the port side injectors. Took forever to rule out bad gas, fuel pumps etc.


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[mvoellinger]

I had the same issue. Loose wiring harness to the port side injectors. Took forever to rule out bad gas, fuel pumps etc.


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can you expand more? Was it just a specific injector or was it the entire rack? Was there a connector to it?

 

[PMC]

Can he test the pressure before he starts replacing parts. The hit an' miss method will fix the problem eventually (maybe) but I think it's better to diagnose the problem rather than throwing parts at it. There are fuel pressure test kits available to test these high pressure pumps. Most of the marine shops that I know of have them in their tool cribs.

Agree completely - Not a fan of mechanics that will diagnose with new parts (not saying this guy is, but happens way too often). Spend the time up-front, find the problem, replace it once. FWIW, the fuel injection system has a Fuel Rail 'Test Port' that you can hookup gauges to. If you see a drop in pressure, you're on the right path.

 

[Bop]

can you expand more? Was it just a specific injector or was it the entire rack? Was there a connector to it?

Not quite sure. He is working on it now ironically. If I wiggle the harness I can get it to surge exactly like what yours does in the video. Appears there is a lose wire going into the harness connector. It did it intermittently previously.

It was a real pain as it doesn't show on the computers or any fuel pressure test. No codes or anything. Found it by luck.


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[Bop]

can you expand more? Was it just a specific injector or was it the entire rack? Was there a connector to it?

Did you get this sorted out? Mine ended up being that someone had put a tester too far in the harness at some point on the female power end and caused an intermittent connection issue. All fixed now and simple but a royal pain to find.