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Optimax problem

C

captdale

Member
Ok. 2010 , 200 hp Optimax DFI. Got good air pressure, good fuel pressure, oil pump primed, good spark, hot new battery. Will not start. If I put a tablespoon on gas into the intake manifold it cranks right up and runs about 3-4 sec. So, not getting fuel. The fuel injectors getting the +12 but not the pulse from the ECU. Swapped ECU's. Same thing. The questiion, is there a sensor such that if the ECU does not see that signal it shuts off the injector pulses ? CD
 
First off, have you run out of warranty? should be 3 years on this model.

Secondly here I'm a little confused. You are putting gas into the intake manifold - as the air intake in front of the reeds??

This motor is direct injected so the gas should go through the two pumps, through the VST to the injectors that feed the fuel rail and then through the direct injectors directly into the cylinder.

If you are not getting fuel to the fuel rails then the problem is upstream of that (VST, high pressure pump etc) or you have a toasted tracker valve (between the air rail and the fuel rail preventing the direct injectors from feeding the cylinders) or an air pressure problem (compressor) feeding the air rail.

You note a couple of technical measurements (seeing 12 v at the injectors) - do you have a DDT or laptop set-up that you are using to diagnose or just going at her with a multi-meter???
 
Hey, thanks for the reply. I did find out what was the problem. I got both good air and fuel pressure with the gauges. Put a NOID on the injector cables and they are all getting good pulse signal. Pulled a plug and it was dry and not even a smell of gas. Pulled one injector and ran the fuel pump. Not a drop out of the rail. Pulled the top off the seperator and ....... YUCKIE ........ Motor had sat for long time and jello all over. Took it apart and cleaned everything. Both low and high pres pumps good and filters clean. The needle on the float was stuck closed so that is the root cause of no fuel in the rail. I guess the good pressure reading was the high pres pump pumping a LOT of air !!! Anyway the ruber tip on the needle was gone so will order a new one of those and should be good to go.

I understand how the motor works. I'm a electronics engineer and have a master mechanic cert. (high performance race cars) so am okay with ECU controlled motors with gobs of sensors. This is the first outboard I've worked on hence the question on the sensors. I know it does not get fuel thru the intake manifold but figured it should at least hickup with some fumes. And it did, showing if it got fuel it would run. I was testing the sensors with a digital meter (not good in all cases of course) so picked up a NOID this morning and was able to verify the ECU was working like it should. I do have a DDT but it has the wrong adapter cable for this motor. Have the right adapter on order so will get a really good look at it when that comes in. In the meantime the digital works okay except for the injector signals. Pulse is too fast for it to react and give a good reading. Guess I could put a scope on it but my scope was at home in the shop and I was 20 miles away. ;) Doesn't matter now as the NOID worked just fine. Got a couple more that I will be working on so should be fun. Couple of complete rebuilds, rings, bearing etc. coming up so by the time thats all done should be pretty good on these motors !! I like these DFI motors. Very high tech and put together just right IMHO. Anyway I do appreciate the input. Lot to learn. I'll post more as the saga continues LOL. CD
 
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