injector pulsing after turning car off...

[JoseMiguel]

I have a very strange issue with a car.

MS2extra running CAS 4/1, semi seq

The car runs great, gives good spark, steady AFR's and whatever you may think of. But for some reason im still not able to understand, when I turn off the car and take the spark plugs out, when I look inside the cylinders, all of them are puddled with fuel...

ECU does turn off when I switch the car off, It does that inmediately (I had an issue once with a car that the ecu stayed on for a few seconds after switching it off).

All of the cylinders have some fuel when I look at them, but specially, cylinder number one. Injectors are wired in the semi-sequential mode (1-4, 2-3).

Here is my educated guess, please tell me if this seems logical.

For some reason, when I turn off the car, injector power is not turned off inmediately. The ECU off provides ground for the injectors and they stay open for a while when I turn off the car. That is the reason why they appear puddled after turning the car off

I know this is fairly straightforward to test but I wont have access to the car until next week so I want to be prepared on what to look for...

[racingmini_mtl]

You need to wire the injectors as per that diagram: http://www.msextra.com/doc/general/ms2external.html. How are you powering your injectors? If they have power while the ECU doesn't then they can remain open.

Jean

[JoseMiguel]

Car was completely wired from the ground up, the car used to have a carbureator so this is a fresh, new complete install by an experienced person (it wasnt me)

Im guessing there is something wrong in the power that goes to the injectors

[JoseMiguel]

Any other thoughts? Is this possible?

[kjones6039]

I personally follow the diagram that Jean posted with the addition of coil power. That is to say, if the fuel pump is not powered (ie. no rpm), then neither are the injectors or the coils. Without power, the injectors will not pass any fuel unless, of course, one or more injectors are stuck open (which I find unlikely).

Ken

[JoseMiguel]

Let me rephrase my question

A powered off ms grounds the injectors? If i power an injector with the ecu off, it stays open or closed?

[kjones6039]

A powered off ms grounds the injectors?

Not that I know of.................

If i power an injector with the ecu off, it stays open or closed?

It should be closed but, the best solution is to avoid powering the injectors when the engine is off in the first place................

Ken

[Sam280Z]

Check out my old fan control post. It explains what happens if you power the injector circuit all the time.

http://msextra.com/forums/viewtopic.php?f=131&t=44105

[JoseMiguel]

Check out my old fan control post. It explains what happens if you power the injector circuit all the time.

http://msextra.com/forums/viewtopic.php?f=131&t=44105

that was VERY informative... so that is probably what is happening on the injectors, in your case it was a fan connected to this outputs

what did you do to work around it?

[racingmini_mtl]

what did you do to work around it?

Wire it correctly.

There is no other solution. Follow the diagram I linked. Having a powered injector connected to an unpowered ECU is bad and will always result in unpredictable behaviour.

Jean

[JoseMiguel]

Thanks for the answer

Im pretty sure the problem is happening there, I cant think of another way that would flood the cylinders in the way this car does...

I didnt wired the car, so Im guessing the person that did the wiring went wrong with that one!

[Sam280Z]

Check for voltage at the injector with the engine off. You should find none.