The car is s4 na and its been running fine for the longest time and now outa no where when I give it any decent throttle % I can see on my UEGO that it richens out to 10.0:1 AFR bogs a bit when it hits that rich and I get zero power and this is with 0+/- correction on the SAFCII. I'm searching and finding nothing anyone have any idea why/how this is happening?

its prob coincidental but my cruise control does not work anymore

 

If you can measure injector duty cycles, do so. You can use a scope, a multimeter with a duty cycle function or perhaps a dwell meter. If you find that IDCs are exactly the same as they once were but you are running crazy rich, then you have an injector issue. I've seen them suddenly fail and get sticky where they dump fuel into the engine.

 

Aaron beat me to it.

 

I dont have access to a scope, but my multimeter is pretty nifty.

are you suggesting I need test it while the engine is under load? that will be a bit tricky. Im assuming the injectors that are giving me guff are my secondaries since the problem doesn't occur in low RPM.

ps;

IDCs?

 

also, a faulty coolant temp sensor or connector to it can cause this. if it suddenly becomes unplugged, it can cause crazy richness.

dpf22

 

I bet this would get picked up by the code checker, I mean two blinking lights... heh


edit: I don't know if the secondaries are to blame since the problem arises right at or right before 3400rpm.

the engine still revs up fine under load after it bogs a second for being so rich, its just noticeably slower at 10.0:1 to 11.0:1 AFR at WOT.

and the code checker came up with all good. I need to get my hands on an oscilloscope...

 

the secondaries resistance wise are out of spec, I just ohm'd them out.

the spec is 1.5-3 ohms and the injectors were 3.5ohms and 4 ohms.

I woulda figured that the higher resistance would have had them to be stuck closed though...