Engine dies when turning on Blower/Bilge/Fat Sac Pumps...

[roosm]

Hi,

I have a Supra Launch SSV from 2001 with Indmar TBI Assault 310.

Today when we were out with the boat we experienced some issues.
First it was hard to start I had to throttle up to get it going. The starter was kind of weak and I blame it on a weak battery after sitting a couple of weeks.

We went out wakeboarding once we got her started but it was running a bit rough especially when trying to get on plane. Once in wakeboarding speed or at idle it was fine.
Then we got some thunder going our way and decided to go back to the dock and wait it out.
We idled back and then suddenly the engine died. It fired back up but now it was running fast idle at about 1200 RPM. Managed to get back to the dock.

Then we went back to the boat to go out again. We brought a new (as in just bought it and charged it up) battery with good voltage.
Now the engine starts fine and idles fine, but if I turn on the blower it will die.
If I turn on a fat sac pump idle speed will drop to about 400 RPM and the engine runs very rough until the ECU (I guess) fixes this by going into high idle at about 1200 RPM.
If I turn on 2 fat sacs pump simultaneously it dies.
Basically as soon as I run any electronics the RPM drops and if I turn on too much the engine stalls.

Voltage is normal and alternator charges the batteries.
I have loosened and cleaned all battery connections (both ends of + and ground wire).

I also noticed that if I try to turn on the bilge the automatic fuse blows. It runs like a second then "click".

Any ideas??

Help please! I am lost!

Ground issue from the dash? But where is the ground?

Mike

[tretter7]

It's gotta be a ground issue, right? The fact that you're blowing a fuse on the bilge tells you it's drawing too much current. But why EVERYTHING is doing it... hmm. I think there is a big ground near the ECM, grounds at the circuit board under the dash. This thread seems to suggest that all switches tie together under there: https://forum.supraboats.com/showthread.php?10968-Needed-Dash-console-wiring-diagram-for-2004-SSV

[roosm]

Hi,

I will report back after a weekend of wakeboarding.
This time around I brought my DTC-checker (a paper clip and a LED-light) to the boat and checked for codes.
It came up with DTC 41 Open IC Circuit.
I removed the distributor cap and loosened and re-tighted the bolts holding the Ignition Control Module slightly.
Then the engine fired right up, had no problem with running any electronics. Back to normal. Anything one can do to make sure that this does not happen again? I replaced the ICM last spring and already it has ground issues...

On a side note I later tried running my Bilge pump manually which somehow worked. Did not trip the auto-fuse...
I remove, re-charge and re-install the batteries so I guess the ground wire, which I run straight from Bilge to battery, works better now. Not sure how bad ground causes fuse to trip, but it works, I am happy...

[CornRickey]

Sounds like your running off of battery and not the alternator. I'd check the alt.

[roosm]

As said in my last post here the issue is now resolved.

But yes, I as running off of the battery and not the alternator. Not sure if this, low voltage, could have caused the bad ground in the IC-circuit leading to the engine troubles..

[CornRickey]

Electronic ignition requires an in voltage to trigger. By turning on the accessories you were dropping below the threshold and the system would shut down.