Efi

i have a 1997 omc/volvopenta 5

i have a 1997 omc/volvopenta 5.7gi at around 2300rpm 1 injector stops working and the engine surges from 2300 back to 1500 and back up again while looking into the throttle body i can see the fuel spray cuts out then sprays again ????? IM GOING CRAZY TRYING TO FIND PROBLEM ANY HELP? THANKS HOAGIE JOE

"Look at the ECM- does it show

"Look at the ECM- does it show GM or Delphi on it? It's possible that the coolant temperature sensor is showing the ECM an overheat condition, whether it's real or not. Is it alternating between the injectors or is only one going off? If it's alternating, it may be in RPM reduction mode due to the input to the ECM. If it's just one going on and off, it could be a few things. The terminal on the injector harness may be loose, the wire may have a break, it could be corroded, the relay may be bad or the driver may have a problem.

You're going to need a digital multi-meter if you want to trace this problem yourself."

"efi thanks jim,ive been havin

"efi thanks jim,ive been havingthis bogging down problem and had fuel pumps replaced,with no change.however,i had the motor pulled for a ring gear problem.while the motor was out i had the manifolds and risers replaced.after the engine was put back in and in the water it ran good for 2 days then it started tobog down againand surge from 2300 back to 1500.only 1 injector keeps going on and off.could the pump relays be bad?this motor is a 5.7gi omc/volvo penta 1997 .your input is appreciated"

"There's only one relay fo

"There's only one relay for the fuel pump and it's the injector that has a problem, not the pump. I would be tracing the wires from the ECM to the injectors and see which has the problem. You can go to Advance Auto Parts and borrow tools but I don't know what they have to lend. You'll need what's called a 'noid light' for the injector harness test. If you have a digital multi-meter, you can check for continuity and shorts, which I would do anyway.

You need to be methodical for this kind of thing and if you don't know the EFI systems, you may want to consider going to an authorized service center."