Okay so my car is idling rich with the stock ecu and with the pfc...my car is completely stock with only downpipe, bonez hf cat and catback. The wideband reads 12.5-13.0 at idle with both the ecu. I've changed the spark plugs, wires, oil, fuel filter, air filter, checked for vacuum leaks(none), replaced all vacuum lines, check valves, and all the sensors checked out good with the pfc and yes my air pump is working. It's been 6 months that I've been trying to fix this problem but i can't figure out the problem...any suggestions would be helpful, thanks.

I've searched trust me I've been researching for 6 months...

 

I would like to have your AFR! Mine is 11.3 at idle! My car is stock with high flow cat and PFC.

I dont think your number is to bad. If i remember you should be at 13-13.5. But let the rotary guru confirme this

Eric

 

My idle is 11.5:1 or so, though I do have 850cc primaries.

If your idle is smooth, I would leave it alone.

 

Thats not rich for these cars. They won't even properly idle at 14.7:1 in most cases.

 

yeah it idles fine with no stumbling...but the problem is I can't get it to pass smog. HCs are 300 at idle(max:100) and 70 at 2500rpm which is good and i don't know the reason why it's so high at idle.

 

If you have the PFC Commander it can be leaned out fairly easy through PIM or INJ settings.

Detailed info ---> https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-make-your-untuned-pfc-basemap-safer-idle-better-no-datalogit-needed-841706/

 

Better yet, refer to post 22 in that thread.

best of luck.

 

yeah i've leaned it out with the pfc before but the HCs are higher when the rpm is at 2500...

 

Is the air pump and it's control system working properly? That's how Mazda passed the smog test.

 

The PFC also turns off the air pump at 2500rpm vs. 3000rpm for the stock ECU, which may have an effect on the higher rpm reading too.

 

Air pump and/or ACV are not working properly for whatever reason. Your idle should read very lean if those are working. What happens is that the idle is actually rich inside the engine, but the ACV directs air to the exhaust ports to lean it out before it reaches the cat.

Is your airpump clutch working properly? Switching actuator on the ACV and its associated vacuum routing good?





The air pump should be working. With vacuum applied directly to the switching actuator the idle should be very lean due to dilution at the exhaust ports. The way it works is that the switching valve is spring loaded so that airpump air will naturally flow directly to the cat. When engine vacuum is applied (like at idle) the valve will lift and secondary air will flow to the exhaust ports. When the ECU wants air to flow directly to the cat (split air) it cuts the vacuum to the switching actuator by engaging the switching solenoid.

see this thread: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/why-engine-so-damn-complicated-part-2-emissions-controls-841963/

 

thanks for the info...i'm sure my acv is working fine along with the solenoid valve, but I guess I'll go back and double check them again. Also thanks for the info of the air pump turning off earlier with the pfc moconnor, I'll by-pass the relay and see if it changes anything.

 

The idle number I quoted was with the air pump off - with it on I am seeing 17:1 or so. If you are running ~13:0 with a functioning air pump then your real AFR is probably 9:1.

 

i got it fixed guys...turns out that the previous owner attempted to replaced the vaccum lines and ended up putting them on back wrong...so all is well and time to go smog. Idles at 15.5 afr btw if anyone was wondering.

 

Glad you got it fixed! I just had a similar issue, except the hose was kinked. Once we tracked it down and replaced it everything was good. =)

-Taranis

 

Good to hear.

 

what hoses are you guys referring to ? Im having a similar issue where I need to set it really rich for it to idle properly ?

 

The hoses that got mixed up was the double throttle one, and the two that plugs onto the uim near the firewall...

 

so just by mixing up those two hoses with each other caused it to idle rich ?

 

yup...i know, hella weird But good news I passed today with flying numbers!!! Time to mod the car now my hesitations gone...