Re: [AMC-List] 1986 Jeep Cherokee clattering valves and black smoke

[Frank Swygert <farna@xxxxxxx>]

Howard, I'm in agreement with Andrew, it that helps! The black smoke
and sooty plugs are a classic indicator of running rich (assuming they
are dry, and the soot in the tailpipe is dry -- if they are "greasy"
black that's burning oil). The loss of power gradually is a classic
sign of a stopped up catalytic converter. As pressure inside the
tailpipe increases, the engine has to work harder just to try to push
the exhaust out, so power decreases and you have to apply more and more 
throttle. Yours obviously isn't plugged all the way, but I'd remove or
replace it. If you can unbolt it for now the thing would be loud, but
you can tell right away if you have to increase throttle or not to get
it to idle right. You also need to replace the oxygen sensor. That
tells the carb how to adjust the idle mixture. I wouldn't do that until 
rebuilding the carb, or getting a factory rebuilt replacement. The
later is more expensive, but also the best move. There is at least one
stepper motor in that carb that might need replacing. 

With the cost of the carb, you might be better off getting the EFI
system from a 89-93 S-10 or Camaro 2.8L from a salvage yard, or the
entire engine. The wiring isn't that difficult, and you'd end up with a 
lot better power and economy. You can't put a 4.0L in that year without 
a lot of firewall work (87+ has about a 2" recess in the firewall for
the 4.0L). If you find a nice 2.5L four it will have more power than
your well worn 2.8L V-6 and will bolt right up to the trans. Of course
you would need the flywheel (and torque converter if auto) and engine
mounts for the four. AMC bought the 2.8L V-6 to have a six cylinder
option, but the carbed version only has a little more power than the
AMC 2.5L four. Not enough to be worth the additional os when they were
new in my opinion, something a lot of people here share -- and not just 
because it's a GM engine in an AMC -- it's a crappy GM engine even when 
in a GM!!


> " From: Howard.Allen@xxxxxxxxxxxxxxxxx
> "
> " Hi;
> " I am a new member located in Limington Maine.  I have owned one
other AMC
> " product  years ago, a 1973 model I bought non running for $50.  Ran 
it for
> " 6 months with a slippling clutch and sold it for $25.  Nice engine
never
> " smoked.  Anyway, this week I purchased a non running 1986 Jeep
Cherokee
> " with a 5 speed transmission and 2.8L V6 engine.  I replaced the
fuel pump
> " and installed a new radiator and battery and started it up.  Hasn't 
run
> " for about 5 months.  Started a little hard but it ran.  It sounded
like a
> " sewing machine but the oil pressure was 40PSI so I let it run a
while.  As
> " it warmed up it ran slower and slower so I cranked the mechanical
throttle
> " stop up to compensate for the time being.  AFter 15minutes the oil
> " pressure was down to 15PSI and the exhaust was black and RPM were
down to
> " 550 with the mechanical throttle stop all the way out.  It finally
stopped
> " running.
> 


=============================================================
Posted by wixList Archiver -- http://www.amxfiles.com/wixlist

_______________________________________________
AMC-List mailing list
AMC-List@xxxxxxxxxxxx
http://www.amc-list.com/mailman/listinfo/amc-list

or go to http://www.amc-list.com