Re: 454 mag problem
 

Is this an inboard or sterndrvie? MEFI3 inboards (454/502) have a "Load Anticapation Mode" that adds IAC counts when shifting, but it does not kill four cylinders. Even the shift interrupt switch (Alpha models) momentarily drops IAC counts and retards timing, but does not kill individual cylinders. Not sure what your mechanic is talking about.

Did you check for trouble codes? You can verfiy if you are "stuck" in some improper operation mode with a scan tool.

What do you mean when you say there was a "broken" injector?

Dave

Re: 454 mag problem
 

the injector had a piece broken off the top plastic part, it is a mefi 3, and it just seems to not have any power, I may not be explaining it right since I am not a mechanic but am just trying to get all the ideas I can, can wiring aroungd the n safety affect the way it runs???

Re: 454 mag problem
 

and also no codes, it actually sounds like its out of time but its not

Re: 454 mag problem
 

No.

Did you double check the firing order?
How was the engine timed?
Did you check for trouble codes???

Dave

Re: 454 mag problem
 

timed from #1 on tdc and with a merc comp. and timing light, firing is correct yes we checked for codes, and no codes

Re: 454 mag problem
 

what is an injector driver curcuit? How would i know if this failed, I know its not a ecu prob. because we swapped them and the problem was still there

Re: 454 mag problem
 

The injector driver circuits are in the ECM. Swapping ECMs should eliminate the actual driver as the cause. You could still have an open circuit in the wire harness. You can get an injector test light (noid light) at most auto parts stores.

Have you been through the trouble shooting procedures in the Merc service manual?

Dave

Re: 454 mag problem
 

nO, i HAVE IT AT A LOCAL SHOP AND i DON'T HAVE A MANUAL and they are stumpped along with me , I just wanna use my boat, I have only had it out 3 or 4 times and now its been down for 6 weeks, so all your help is appreciated sorry about the caps, cap lock

Re: 454 mag problem
 

Ok Then Lets Stop Jumping All Over The Place And Go To Basics...
Has Anyone Done A Cylinder Misire Test Ie Kill Cylinder And Look For A Drop In Rpms

Re: 454 mag problem
 

yes at first but I would have to do it again to tell you which ones but I belive it was like 2 on each side