sefippoly

ok here we go......88 cherokee, 4.0 running rich, black smoke out tail pipe, runs ok, but not great. can tell its running rich. all plugs are black. checked, coolant temp sensor, its good. iat sensor, good. made a slight adjustment to tps. crank sensor good. fuel presure is 34 with vacuum, 41 with out. checked map, even tried an known good one. bat voltage is good. installed new o2 sensor, (bosch). have another ecm and tried it.....no difference with anything i have done.

WHAT AM I MISSING!!!!!!

I will thank all now for your help. trying to get this going, leaving town later this week and wont be back till after the new year. daughter need the vehicle.


kevin

BlueXJ

How are you checking the different sensors you mentioned? This is my guide for checking sensors. See if you get the same readings as these.
http://www.lunghd.com/Tech_Articles/...iagnostics.htm

If this doesn't help then PM me.

76ANTHONY

ohhhh come on blue, i want ta hear what fixes this, not top secret area 51 pm'ing

sefippoly

bluexj, that was what i was using to check the sensors. i did just readjust the throttle body, someone had adjusted the minimum idle screw way out and then tweaked the tab on the shaft. fixed that and readjusted the tps. cant see any thing right now, to dang dark out. will check tomorow and let you know.

thanks kevin

sefippoly

well i think i am on to sumthin, with the last tweek on the trottle body, a whole lot less smoke, running better. i am driving it to work tomorrow, will see how it does. i need to check the iac, idling a little low now. throttle body was gummed up pretty bad. it had a plugged pcv tube, so you can guess the kind of mess it made, looks like it went unchecked for quite some time.

kevin

cheapJeeper

Sounds like a candidate for seafoam?

BlueXJ

Glad you are making progress. It is often several little things and not one big fix 76Anthony. The thing about Renix is you can check everything and when it gets hot those numbers change so they are not always true to specs. Most is just being consistant with your checking.
If you clean the throttle body and intake with Seafoam as suggested be prepared for it to run like crap until it burns all that cleaner out of it's system. Clean is good however you decide to do it.

76ANTHONY

very valuable thread, mines running black smoke at the azz when reved up, so im gonna star checking

BuckB91XJ

Have you checked for vacuum leaks around the Throttle body, intake manifold, all hoses and fittings on intake and valvecover area? Something is making the computer think the engine needs more fuel...like it is getting extra air from somewhere. Just racking my brain trying to think of something you haven't already tried. You've checked all the same things I would have checked except for a vacuum leak. Hope this helps, Brother.