1996 Suzuki DT115 EFI Fuel Pump / ECU problem

[Seacraft20]

Does anyone know how to test an ecu for the fuel pump output? I know that it works from switching the ground on and off. Here is my dilemma. Electric pump wasn't working. I checked voltage with meter and had 12.6 volts. Figured pump was bad and bought another. Same issue with the new pump. Nothing would happen. but if I checked the plug I had voltage. What I found out was the second there was a load put on that circuit it went to 0 volts. It shut right down. There arent any relays or fuses inline. The circuit goes directly to the ecu. I checked the ground for the ecu, even hooked the ground direct to the battery. Still nothing. Any help is greatly appreciated. The lowest price I can find on a new ECU is 1650.00.

 

[Marion Moore]

When I purchased my 1996 DT115 EFI back in 2007 the previous owner must have had issues with the switched ECU 12VDC ECU high pressure fuel pump output so he found a constant 12VDC wire under the hood and spliced into it to provide power for the HPFP. It worked but not ideal as the pump ran 100% of the time and relied on the fuel pressure regulator to recycle the unneeded fuel. Eventually I was able to buy a couple of parts motors and used the ECU off of one to fix the issue. Look hard. You will eventually find a used ECU for $800 - $1000 somewhere. I don't have my shop manual in front of me ( I strongly suggest you buy one) to suggest troubleshooting steps but I'll bet the ECU is your issue.

 

[Marion Moore]

Troubleshooting reveled the pulser coil peak voltage was lower than the service manual allowed. I changed the pulser coil with a spare I had, received 9VDC peak output, and verified the engine was charging the battery.