Re: 1990 Mustang 2.3 #3 Cyl dead
Lloyd Cimprich wrote:
> I have a 1990 2.3 Mustang that suddenly started a solid misfire with loss of
> power. When I asked if there was and unusual bang, crunch, clatter, etc.
> just before the loss of power the answer was no. When I went to drive the
> car home I am quite sure that for a brief second it ran on all four.
> When I pulled the plugs all were fine except #3 which had large (not oily)
> deposits on the centre and side electrode.
> I replaced plugs with new with no improvement. I quickly removed the plugs
> and tested compression, throttle closed and engine cool. This showed # 3 at
> 30 and rest at 90. Adding a bit of oil to #3 gave 40.
> At the suggestion of a local rebuilder I removed rocker cover and checked
> cam. Sure enough the lobes were very worn, looked like about 1/16" had been
> worn off all lobes. When I reported this to the rebuilder he was quite
> confident this (cam wear) was my problem and suggested I install a cam kit
> (about $200) or bring head in for rebuild/cam kit.
> Any advice/insight would be appreciated, especially as to why the cam would
> have been so severely worn.
Extremely unlikely that the worn cam is the culprit, though if it's worn
that much it couldn't hurt to replace it once you fix the real problem.
You're losing a LOT of compression in that cylinder. You could have
any number of problems that can only be ruled out through testing:
1. Worn rings
2. Worn valve(s) or valve seats
3. Blown head gasket
4. Cracked head
Have your mechanic check things out before you waste money on the cam
(which probably won't help anyway...if it was the cam you'd be losing
compression all over, not just markedly on one cylinder).