Very lean at idle RPM/MAP problem

[jfpilla]

Sounded like such a good possibility. Back to the drawing board.

[hpcubed]

This is probably not the problem. But when you first start the car the air injection pump turns on. So set the air injuection pump "turn on temp" to max so it does not turn on. I was stumped by my lean AFR on start up. When I turn the air pump off, wide band matches commanded.

[jfpilla]

This is probably not the problem. But when you first start the car the air injection pump turns on. So set the air injuection pump "turn on temp" to max so it does not turn on. I was stumped by my lean AFR on start up. When I turn the air pump off, wide band matches commanded.

HP thanks for the info. I didn't try it because the others said they had removed the pump. I started my car today in SD and used the BI-D controls for AFR and it went right to the AFR I set. I turned it on and off a few times and the AFR followed. I also lowered Charge Temperature Blending at 0 and 10 by .12 and that "seemed" to work but I want to see what happens at -7*C IAT startup. I will try turning off the pump after that.


Are those with lean starts using a cold air intake?

[jfpilla]

HPcubed
I programmed out the AIR Pump this morning. That was it for me also. It followed commanded right from the startup. I then put back the pump and it went to 18.65:1. I'm confident that is it for my car. Doubt it would run with the same feel that lean. Glad you tried it. I feel a lot better knowing 18:1 is not at the engine.
Joe

[WicketMike]

does this have to do with A.I.R. ? i dont have it and i turned the codes off.

what table are you guys talking about to do the "turn off temp"

would that be the B0203 table? just raise that to 140 ?

thanks

[jfpilla]

does this have to do with A.I.R. ? i dont have it and i turned the codes off.

what table are you guys talking about to do the "turn off temp"

would that be the B0203 table? just raise that to 140 ?

thanks

Did you disable or remove the pump? If so your issue must come from something else.
Yes, B0203, 140*C.

Joe

[Black02SS]

Mine (B0203) is set to 256*F. I don't even have the pump in my car. LOL

[VetPet]

Maybe I have this wrong but isn't the A.I.R. pump used during cold start to inject air into the manifolds in order to get the cats heated up as quickly as possible? The 02 sensors are not in play during this period of open loop operation as I understand it. If this is so, I would definitely expect the AFR's to be leaner than commanded. Does anyone have an AFR reading for a stock engine during cold start? There has to be some enrichment for cold start in order to get the engine started and keep it running. What table(s) are referenced during cold start operation? There's something to be learned from this thread and I'm a newbie trying to expand my knowledge.

[jfpilla]

Vetpet
The AIR Pump injects air into the manifolds to accelerate burning of the richer fuel created by added fuel for start up, less than efficient burning by a cold engine and the cats not being hot enough to clean the gases emitted. This process probably helps the cats heat up too. As for an Airflow reading at start up, if you have an AIR pump, it will look lean. Mine is 18.62:1, or so, with no MAF. With the pump disabled, it's a mess for a short time and then follows commanded. I don't see any useful A/F #'s before it goes to commanded. It might be my WB 02 is lazy, though. I've had it a while.

Let me add, if the pump is on with the MAF, it should be lean for a bit.

Your not a newbie. No more self deprecation please. Be .
Joe

[eboggs_jkvl]

If you want to disable the AIR, wouldn't the B0204 set to 1 RPM be the catch all that would work? My AIR & EGR are in the attic and I've put all of the codes to sleep. Would I need to set this to stop the AIR from inducing action in the PCM? Right now, it is set at 2825 RPM. It may be appropriate to set B0205 to 1 too.


Elmer