Okay, so I have been battling the C.E. light for months now. It came up as possiblily a bad injector or bad spark plugs, so I changed the spark plugs and wires and also bought some "newer" injectors. My motor has about 190k on it, the injectors I bought had about 98k on them, still good and clean, so I threw them in. Ran good for about a day and then the check engine light came back on. It starts to run bad when the temp hits about 210, then and I swear, the thing runs like it has a bigger cam in it. It sort of shakes and I can smell rich fuel. Could it be I went the cheap way and didnt do the cap and rotor when I did the spark plugs. I dont have a scanner on me right now, so I cant scan it but that is the only thing I can think of. Anyone else ever have this problem.

 

Have you checked out your O2 Sensors?

 

U siad you dont have a scanner right now but when you get a hold of it read the codes.. If im not mistaking its sounds like your o2 sensor (x2 ^^) (upstream) has gone bad.. So the rich smell is the vehicle running in open loop..

Or possible when you replaced the injectors they did not set right in the injector ports and is leaking fuel..

The puzzling part is when you say it happens after reaching operating temps..

 

^^ I really liek your avatar pic!

 

I haven't had this problem, but could one or more of the injectors be getting heat soaked? Think there was a TSB on Jeeps regarding this type of problem on the #3 cylinder (off the top of my head, I may be mistaken). Pretty sure the solution is to insulate the injectors with heat wrap, something along those lines. One of the guys with a 97+ should be able to chime in better on this issue.

 

does your start with a dodge key if so you dont need a scanner just turn the key on off on off on and count the lights

 

if it get worse after warming up, if it idles bad, if it consumes more, if it stalls, it is usually a broken pre o2 sensor(actually it may not be broken but out of specs).it may happen anytime.(system detects repeating problems then flashes check engine light)

i faced this twice on different cars,all symptoms were similar. after going in limp mode, performance is also degraded. fuel mixture is rich and car fuel trims statistics to decide how to run. it is surely be in open mode and will not use o2 sensor like it does a full throttle.

 

Good point but if when he reads the codes and he get a cylinder 3 misfire than that his cause of heat soak.. HEat sleeve problem solved.. But when it runs rich thats when it becomes an o2 problem or injector problem.

 

Thanks, i need to do the same pic with the hood closed.

 

I had a friend tell me about the heat problem in the number 3 cylinder, I think I might heat wrap it and see where it takes me. I am planning on getting my scanner back this weekend so I'll see, thanks for the help guys.

 

A coolant temp sensor that is reading incorrectly can cause the engine to run too rich. Cycle the ignition key three times and read the code.

 

It makes perfect sense. You jeep basically ignores the o2 sensor readouts until the coolant temp sensor says that the jeep is at operating temperature. Until then it runs off pre-programmed a/f ratio values.


x3 on the o2 sensor (upstream - before cat)