DF115 EFI 4-stroke Suzuki Check Engine trouble

[firechief]

Just remotorised with a brand-new DF115 4-stroke Suzuki connected to two batteries (equipment & starting battery) with a diode-bridge in between (sorry for possible typo's).After some minutes CHECK ENGINE lights and the beep sounds once about every two seconds. Output voltage shows around 16 volts as off about 2500 RPM. Dealer as well as national importcompany say they haven't seen this before. Computeranalysing at dealer's shows no problems. Anybody familiar to this problem?

[DJ]

Does the problem exist when hooked to only ONE battery?

[JB]

Howdy, Firechief.If the codes on your DF115 are the same as my DF70, single beeps plus a check engine light indicate overcharging.The problem may be that your electrical setup has damaged the regulator, or it may simply be reacting to leakage in your battery setup, seeing too much voltage. Few rectifier diodes have enough reverse impedance to protect the voltage regulator from overload.Do as DJ suggests. Disconnect one battery (the deep cycle). If it behaves properly then, replace your diode network with a battery switch so that only one battery is connected at a time.If it repeats the symptom with only one battery, check your regulator, it may have been shorted by overload.Good luck, and let us know what you find.

[lakensea]

JB, you are correct. The single beep/check engine light indicates incorrect voltage - too high or too low. We've had good luck using the West Marine battery combiner when hooking up 2 batteries to one engine. As said above, run it with one battery, but I suspect you've fried the voltage regulator. One thing you don't want to do is mess around with voltages on these engines - you'll hurt the ECU (computer) just like voltage spikes will kill your home computer. Make sure your battery connections are good and clean - and most important use lock washers or lock nuts on the cable ends.

[firechief]

Thanks DJ, JB, Lakensea. I hope that the voltage regulator is still in good shape, as the official suzuki softwaretest at dealer's didn't show up any errors or malfunctions. It seems that the diode-switch provokes a peak-voltage.I will follow up your suggestions upcoming week and I'll let you know my findings and (hopefull) solution.

[firechief]

Disconnected the diode-switch and problems were solved! Tried another brand & type switch and problem showed up again. So computer and voltageregulator do react on diode-switches in general.Anybody got a solution when hooking up 2 batteries. They must be separate so that they can't exhaust each other as a matter of safety.Perhaps some diode-switch espacially for Suzuki engines?

[DanMcK]

Hello firechief, I found a nice article on battery installation. Here is the link- web page Enjoy.