1993 Ford Ranger Spark Plug Analysis

Status
Not open for further replies.
Joined
Nov 25, 2011
Messages
419
Location
Seattle, WA
I'm having random misses at idle when warm with no Check Engine light on a 1993 Ranger 4.0.

It also has intermittent tapping, which I believe is the pushrods/rockers, but I will be tackling this later.

I pulled the plugs, and found it interesting. The whole left bank is much more fouled than the right.

What do you guys think? Expert opinions needed!

[Linked Image]

[Linked Image]

[Linked Image]

[Linked Image]
 
How many miles on this '93?

Was the "waste spark" system used on that engine? They say incorrect spark plugs on one bank will take a beating due to the polarity of the spark.

However, "double platinum" is supposed to negate the imbalance. Did operation improve with the new plugs?

Bad valve seals on one bank? Perhaps head work on the other side years before?
 
Originally Posted by Kira
How many miles on this '93?

Was the "waste spark" system used on that engine? They say incorrect spark plugs on one bank will take a beating due to the polarity of the spark.

However, "double platinum" is supposed to negate the imbalance. Did operation improve with the new plugs?

Bad valve seals on one bank? Perhaps head work on the other side years before?


Very little history on this vehicle, aside from the visual inspection. I just got this in a trade.

The engine I would guess has ~150k-200k on it.

Yes, it's better with the new plugs. However, I wonder if the skip will return shortly.

Also, I did pull a left-bank "lean" code with the old plugs. They were hand-tight, so I wondered if they were leaking compression causing the lean..
 
Last edited:
if anything, the lean bank looks healthy and the other bank looks like it's running rich.

Wonder if a PCV return or other waste line is feeding one side of the intake, though any waste fumes shouldn't cause anything so much as the difference shown.
 
Originally Posted by meep
if anything, the lean bank looks healthy and the other bank looks like it's running rich.


My understanding is that Cyl 4,5,6 is the left bank (drivers side). Are you saying the sooty plugs are normal vs the very clean Cyl 1,2,3?
 
I've read that at 150-200K all the exhaust sensors should be changed. Look 'em up - they're cheap.

I'm with that finger tight thing. Run her sane for a bit. She might like it.

Be glad you didn't shoot a hole somewhere under the hood....or bang the heck out of the threads on the way out.
 
Doesn't appear to burn oil.

It has two O2 sensors, one on each side. I have ordered a new left sensor. Should be here by Friday.
 
Status
Not open for further replies.
Back
Top