Okay so i have a mostly stock 89 automatic. (Mods are 703 injectors (cleaned, rebuilt, tested), closed to open cooling system, high flow air filter (in stock box without restriction). Anyway the only other thing that is different is the intake air temp sensor is out of a 93 with the old plug wired to it, still in the stock location. For about the past week it has been running rich (at least by smell from the exhaust it is), really eating some gas (no visible leaks), and idling pretty crappy (below 500 always fluctuating, only with it in drive though, shoots up to under 1000 while in park). Anyway logic would tell me all these things are connected but how? I figure i would ask and see if anyone has any idea where to start checking. Thanks a bunch!

 

How old is the o2 sensor?

Could be that, could be a vacuum leak, could be a TPS bad or out of adjustment, could be that you need to do a simple tune up and ground cleaning.

 

yep forgot to mention all of that, completely went through the whole thing about three months ago, o2 sensor (ngk), tps sensor (have checked adjustment multiple times), fully cleaned throttle body (off car with new gasket), plugs (champion copper), plug wires (napa), cap, rotor, fuel filter, most grounds have all been refreshed/changed (thanks cruiser ), new valve cover gasket, oil filter adapter o rings, pretty much all new vac lines (bought the whole new harness to the left of the air cleaner so everything was new), egr valve (old one was stuck), ummm yeah. Its basically new!

 

Bump (sorry had to its totally frustrating!)

 

Map sensor related possibly. Make sure there's no vac leak even with the new lines. There's also a coolant sensor that helps the fuel injection system gauge fuel consumption. If those two have any issues it will throw off.

You can use this link to help diagnose the sensors in the system...

http://www.lunghd.com/Tech_Articles/...iagnostics.htm

 

Double check the line to the MAP as suggested.

Are your intake manifold bolts loose by chance?

Do the sensor tests on the CTS and IAT. Sure the plug /wire mod on the IAT is good?

 

What about the sync pulse sensor in the distributor , doesn't that control the firing order of the injectors? If the sensor fails doesn't the computer fire all the injectors at once, causing it to run rich?

 

Not really. Affects idle emissions mostly and you wouldn't know if it was bad.

Unplug your dizzy and start your Jeep.

 

Ah okay, thanks for clarifying cruiser

 

Go do it. Really. LOL.

 

lol, I for sure will, probably tomorrow morning when I have time to play with it.

 

did you check the exhaust manifold for cracks?

 

checked the exhaust for cracks (as best i could see from all angles) it looked good. Most likely will do my old school tranny fluid smoke trick to really check it out and see if there are any leaks. Unplugged the IAT and noticed a definate change in engine sound so that tells me it is working. In park idle its not as bad but in idle at a stop light its idling crazy low and just about to the point it want to die. Will definately check out the temp sensor tonight. Only other thing is the fuel pump or regulator would this possible cause some of my problems? It runs out fine while driving its just idling thats killing me. Also the fuel consumption i normally have been getting around 260-270 a tank which sucks anyway but pulled in to the station today since the dummy light came on and the mileage was 215! So roughly 50 miles less to a tank means its definately drinking gas like a cold beer on a hot day! Any help is always appreciated

Also any idea where to get the MAP sensor vac line? Nobody can seem to locate it and i figure it can't be more than a couple bucks, every other one is new so might as well get that one too!

 

4th relay back in that set on the passenger inner fender is the O2 sensor heater relay. Try swapping it with another or replacing it with a spare.

 

Okay so tried that swapped with the ac relay and no change, ac still works so that tells me the relay was good. here is a pic at idle in drive sitting at a stoplight look at how low the rpm's are