Thread:

454 mag

Originally Posted by speen

I have a 454 mag with whipple that stumbles between 2200 and 2500 rpm just had ecu reprogrammed and still does it any suggestions also just had a tune up.

Hang a fuel pressure test gauge on it. See if your fuel pressure is dropping off at that point.

Originally Posted by EVILFORCE

A lot of variables to concider. I doubt it is fuel presure. It would run out of power at higher RPM. Sounds like a timing issue. Maybe a map sensor. What is your control system, Dist or crank trigger. Need more info.

All possibilities...I always just make sure the easy things are verified first. Pumps start to go out and will provide plenty of fuel up to a certain point sometimes. Making sure the fuel is there clears the pump, filter and lines. Then, as you said, start looking at sensors and timing.

The 454 Mag motors still had distributors, so lots of possibilities lie there as well.

If he recently re-programmed the ECM, we don't know if it was happening BEFORE that as well?? Additionally, I would think they would have seen a sensor fault while plugged in.

I would also want to know what the TPS readings were at idle and WOT to make sure it's getting a full swing.

You REALLY need to check the fuel pressure. Of course, it could be several other components causing your issue(s), but remember that Whipple does a piggyback fuel controller (or used to), which would start adding more fuel pressure at about that point. Boost is ramping up, etc.