454 mag problem
 

Its only running on like 4 or 5 cylinders, we've already checked all of the obvious, it happened all the sudden and compresion is fine, any clues?

Re: 454 mag problem
 

fuel or spark?
Check rotor/ cap for arching isolate dropping cylinders.

I had a problem with the shift interupt micro switch causing to shut down cylinders

Re: 454 mag problem
 

EFI/MPI? Not much info to work with. A failure of one of the injector driver circuits will suddenly take out 4 cylinders. Just a WAG.

Dave

Re: 454 mag problem
 

MPI, could both of you guys elaborate, because I did have a broken injector and a nuetrel saftey switch go bad, which is wired around right now

Re: 454 mag problem
 

only 92 hours also, we just had a head rework from a valve seat issue and now this?????? 6 weeks down and counting, there goes the summer

Re: 454 mag problem
 

Need more info!

What year? VST or Cool Fuel?

Did the problem start immediately after reassembly from head work? Or did it run fine for a few hours, then developed a new problem?

Did you check for trouble codes?

What does "checked the obvious stuff" mean?

Have you checked fuel pressure?

Which cylinders are missing?

Dave

Re: 454 mag problem
 

2000
cool fuel
It all happened at the same time, dropped a valve seat
plugs, wires cap, rotor all checked
fuel pressure 42-43
Im not sure which cylinders, but can find out tomorow

Re: 454 mag problem
 

I just got back from the shop and he said the shift micro shuts down 4 cylders to shift into gear and if I wired around the nuetrel saftey switch it is probably stuck in that mode, what do you think, we are trying to fix that now

Re: 454 mag problem
 

is it a Merc or Omc if Merc alpha or bravo?????? if alpha it has a shift interruptor if bravo it does not. only Omc shuts indv. cyclinders Merc grounds the coil for a milisecond.

Re: 454 mag problem
 

It is a Bravo, what does grounding the coil do