07 DF150, bad ECU ?

[cprice11]

I just got the boat over the trailer after a one hour + cruse when the starboard engine stopped and would not restart. Both engines ran fine before this. No alarms on the Tach. Checking the engine at home; found all fuses good, fuel was in the vst, could hear fuel pump run for about 3 seconds after turning the key on, good spark on the spark plug but the plug was dry (no fuel on it) after trying to start it. Thinking about switching the ECU's motor to motor. Any ideas, thanks.

Motors have 290 hours Exhaust holes were plugged with mud (wasp nest)

[Harper]

You can try swapping ECUs. Won't hurt anything, of course. But I doubt that that is the problem. I assume you mean that it will crank okay but not fire up. More likely something in the fuel system, high pressure pump or filter. Most of the time, unless you do something to specifically cause it, (some sort of high voltage transient, wrong polarization, etc) most electronics will not fail late in the life of the equipment. Most failures of electronics are in the early life of equipment. In other words if the ECU was going to fail for some reason, it was much more likely in the first 50 hours or so. Anyway, that's my story and I'm stickin' to it.

Check your whole fuel system real good, both high and low pressure sides. Pressure at the fuel rail, filters, dirt, water, everything.

You have spark, so I'm guessing electrical connections are probably okay, but don't completely rule them out. Low voltages on our engines play hell with the ECU. I'm talking about battery condition and wiring/cable condition, including the white wire.

[cprice11]

Thanks; will check . motor almost starts, acts like there is a little fuel in the cylinders but not enough.

[cprice11]

I changed the high and low pressure fuel filters( old ones turned out to be good) , checked the filter on the bottom of the HP pump, it was clean. The Vapor separation tank had plenty of fuel in it. I swapped the ECU 's between the two motors. ECU'$ good. Starboard motor tries to fire.( over revs the starter motor and a little smoke comes out the prop exhaust). Any ideas? How do you see if the injectors are working ? The pulse to fire them is probably too short to see on a volt meter. The hose to the injector pipe feels firm. I can hear the HP pump run when the key is turned on. Don't have a pressure gauge. Does the ECU directly fire the injectors? Thanks for any Info.

[Harper]

Have you done any deep dive into the electrical system yet (wires, battery cables, connectors, etc)? Corrosion can be hidden up inside the insulation on your wires and battery cables.

[redlowrey]

it sounds like a fuel delivery problem it makes it a bit harder if you don’t know what the fuel pressure is. Turn the key on and off a few times to build up pressure turn the key off then crack the fuel pressure rail, you will know if it has plenty of pressure, be careful.
If the spring in the pressure regulator has failed it will just dump fuel into the vst instead of keeping the rail pressure at 40 psi, or the rubber grommet has failed in the vst dumping fuel.

If all the plugs were dry it would indicate it is not getting enough starting fuel, low fuel pressure,it could also do that by the computer, you did check and make sure you had good battery voltage at the injectors.

Check the fuel pressure and if you are confident the pressure is good, come back on the forum and I will tell you what to check electronically.

[cprice11]

Made more checks: cracked open the bolt on top the fuel rail, fuel sprayed out. Checked the battery voltage at the starter, 15v with 2 battery's and charger on, don't ' think I can get a good voltage reading with the injectors pulsing on and off. service manual says to listen for clicks, can't hear over cranking motor.
I Cleaned ground connection over ECM and fuse box. checked spark plugs after cranking a few seconds, some fuel on all of them. Motor fires for a half second and dies. Probably needs to be plugged into a computer.

[Moonlighter]

At this stage, rather than continue to throw parts at it and guess, I would get it connected up to the Suzuki Diagnostic Software computer and a mechanic who has expertise with that system can check codes and use the software to run various tests, and will most likely diagnose it inside 30 minites.

[redlowrey]

If you have fuel on the plugs lift the warm up lever so you can open the throttle, then crank it over,I was going to suggest that first but you said there was no fuel on the plugs.

The iac valve may not be bypassing enough air when cranking and with the throttle being completely closed there’s no way it will start and idle, that’s why it try’s to start but it won’t.

A common problem, tell tale sign fuel on the plugs.

[Harper]

If you have fuel on the plugs lift the warm up lever so you can open the throttle, then crank it over,I was going to suggest that first but you said there was no fuel on the plugs.

The iac valve may not be bypassing enough air when cranking and with the throttle being completely closed there’s no way it will start and idle, that’s why it try’s to start but it won’t.

A common problem, tell tale sign fuel on the plugs.

'07 DF150 has no warmup lever. And not sure that he can crank with the throttle slightly opened either, since the neutral switch might prevent that. Might be able to push in the button at the center of the throttle lever pivot point to disengage the shift linkage and then crack open the throttle and crank. I've never tried it, so not sure.

[cprice11]

I will try it. Don't have a warm up lever but I can open the throttle a little out of gear. Strange it all the sudden starting acting up after 12 years.
Will be a while before I can work on it again. Thanks

[redlowrey]

I thought the early ones had a warm up lever and late had a throttle only switch like the 200 onwards.
Throttle only allows you to open the throttle with out using the shifter, the same as the warm up lever.

[cprice11]

Throttled the motor up as suggested, motor started and ran very rough for a few seconds till I turned it off . Probably bad fuel air mixture and cold engine .
Checked the IAC Resistance between pins as per the service manual. two readings were very, low probable short. Will get a new valve , Thanks Red.

[redlowrey]

I was pretty confident it would start once you opened the throttle, especially when you said you had fuel on the plugs. Make sure that you have correctly connected your meter right because if you haven't you will get wrong readings, The easyest way to check the valve is to remove it, hold your finger on the pintle and get some one to turn the key on and off and see if it screws in and out.
Some time they only need a squirt of wd40 on the thread, the pintle jams.

[redlowrey]

I was pretty confident it would start once you opened the throttle, especially when you said you had fuel on the plugs. Make sure that you have correctly connected your meter right because if you haven't you will get wrong readings, The easyest way to check the valve is to remove it, hold your finger on the pintle and get some one to turn the key on and off and see if it screws in and out.
Some time they only need a squirt of wd40 on the thread, the pintle jams.

I should of added, get some throttle body cleaner, open the throttle wide open and clean the under side of the throttle plate and the body.
What has happened because the iac valve pintle did not move on the command when the key was turned on, no air could get past the throttle plate, it probably has never been cleaned, carbon and gunk build up on the under side of the throttle plate completely blocking any air that would travel past it, so there is no way the engine would be able to idle.