hello folks,

first time posting so thought i'd ask for some help..

i have a 88' cherokee 4.0. my oldest son blew the head gasket so i had the head rebuilt, installed new radiator, hoses, water pump, thermostat, coolant reservoir with new cap, belt, alternator, battery,oxygen sensor that is on the header and new cap, rotor plugs and wires.
the prob i'm having is it still runs warm, and i'm getting carbon fouling on the plugs. the fuel mileage is in the tank and it seems to run a little rough, more of a surge than a miss if that makes sense.

i've checked for vac. leaks and water leaks etc. all the basic stuff so i'm curious if there is another sensor(s) that are making things wacky.

not expecting a miracle but a kick in the right direction would be greatly appreciated.

regards,
brian

 

any ideas...

 

Did you mess with the timing?

 

What brand o2 sensor did you use?

 

i have not checked the timing, which i'm doing this weekend. the distributor was never messed with so i never checked it..

the o2 sensor i believe is a bosch, i've heard the mopar are better

 

i know its more of a gm problem but maybe a ignition control modual

 

Some info that would be helpful:

How warm is warm, in degrees?

Is it setting any codes?

Is it smoking black out the tail pipe? If the plugs are fouling from too much fuel, the converter may overheat and melt down.

 

Get out the old multimeter http://www.lunghd.com/Tech_Articles/...iagnostics.htm you can't mess with the timing on the 87 and up 4.0 ( gotta clarify years and engine before people start *****ing) anyhow there are lots of senate that will cause you to foul your plugs. Test everything as shown above. With the overheating could be a few things. Did you get the stock style radiator? Did you flush the block and heater core real good? Surging could be the map or egr. Start a testing. Once you've diagnosed and fixed any sensor problems you may find your problem has disappeared.... but make sure to give the block a food flush. Ohhhh ya... one more thing. Did you install the head gasket right side up?

 

yep the head gasket was installed right side up.. as far as the temp goes it runs like just under 200 sometimes, i haven't heard it back feed and everything was flushed. the radiator is factory style and it was all burped and bled once it was installed.

it is getting black sute around the tail pipe.

thanks for the link...i did notice a crack in what i believe is the warm tube that comes from the maniflod into the header.. think that might be messing with the o2 sensor

 

The steel tube coming from the exhaust is for your egr. 200 is just right.

 

so with the egr tube being cracked that could be whats causing the fowling? i'm still gonna the other units but i probably should get that fixed first.

 

I don't think it will cause the fooling but it us important to get fixed.