496 mag idle problem
 

I have a 496 mag that will die sporadically, only at low throttle or idle. The fuel pumps will run, as if they are trying to prime the engine at initial start up but they will not stop running and motor will not start. Turn off the key and same problem, pumps just run and run.

Now it gets more confusing, I can turn off the battery to the engine and turn it back on and everything works and runs fine (for a while then it will die again).

I live in semi-remote Alaska and the only service guy here cannot figure it out. It gives no error codes on his laptop.

Any ideas?? There is no other service department where I live any help would be appreciated.

It sounds initially like an ECM failure (however unlikely) but without the ability to survey the situation myself no-one can be sure. Your going to have a tough time figuring that one out without the benefit of a qualified service person.

Start first with an IAC reset and make sure all battery conductors, and secondary connections, grounds and main power conductors are clean corrosion free and secure. You'd be amazed what kind of trouble poor grounds can cause.

Wow, thanks for the quick response. How does one reset the IAC. (Idle Air Control I take it?)

Is this something I can do?

You cannot reset the IAC (yes, Idle Air Control) yourself, a qualified service technician must do that, or at least someone with access to and knowledge of the Mercury diagnostic equipment, IE: the Laptop or the Scan tool. Best of luck I'm sorry I could not be of more assistance.

You should also double check the throttle body's butterfly setting.. ;) Jamie / Lakeside

.

there is also a small passage in the throttle body above the throttle plate which has a small square piece of foam type element in it. this the iac passage. at times it as well as the iac can build up a residue known as throttle body coaxing. essentially this means to clean the entire throttle body, passages, annd throttle blade .

Thanks for all the input. I am trying the ideas you guys have.

Is there a way to test the ECM? I am being told there is not. Awfully expensive for a new one if that is not the problem.