MPI fuel injection question
 

Do injectors on the MPI system on the 454 MAG MPI need to be replaced with age/use? I was told the ethanol blended gas may cause issues. What are signs the injectors need to be serviced? I've been experiencing rough idle and loss of top end/rpm, but relatively good fuel economy. Have 1100+ hours on MPI system, 200 on rebuilt engine, new plugs/rotor/cap. Will get compression test but just wondering if it could be fuel delivery. Thanks

It might be worth while to pull the injectors and have them cleaned and flow tested. I did this to my injectors and found several that had fair to poor spray patterns, one of which leaned out bad enough to cause the valve seat to fail.

Most places will give you a before and after results for each injector.

In addition they (or you) can check the resistance of each injector which is usually about 11-14 ohms for saturated type injectors. If the resistance is off you may want to replace the injectors.

Here is the place I use for injectors. Great pricing versus stock Merc.


www.fiveomotorsport.com

If you need a Keihin style (Honda) injector (which was used on some Mercs) that have a higher flow rating, RC Injection in Torrance, CA has some.