5.0L MPI wont start !

[Damien.]

Hi all.

Having some problems with a Merc 5.0 MPI.

The damn engine just wont fire. Fuel pressure is good, air intake is clear but the spark is rather strange. I can only seem to get a spark out of 3 of the 8 leads, would this be a new cap/rotor arm issue or is it something else ?

Thanks.

 

[guyjg]

I can only seem to get a spark out of 3 of the 8 leads, would this be a new cap/rotor arm issue or is it something else ?

What year? It could be part of the problem. Look at the cap and rotor; are they corroded? Replace them. More likely the plug wires need replaced. How old are the wires?

 

[Damien.]

A good spark is coming from the master lead, IE; the lead from the coil to the distributor unit but there is a weak spark and in some cases no spark coming from the unit itself.

Would I be right in saying the cap and rotor arm need replacing ?

 

[guyjg]

Yes, the cap may be carbon tracking, cracked or the rotor burned.

 

[Damien.]

Cap and arm on order.

That said the arm isn't in stock for another week.

Will post results ASAP.