I am getting code 55 which is fuel system lean only during open loop. I scaled back my PE tables 800-1200 50% and now my O2s read 1xx/1xx during open loop. However when I reach closed loop, they are in the 3xx-4xx range.

Now try explaining PE is only using during closed loop.

 

O2 readings aren't even close to reliable before going into closed loop, that's the whole point to having open loop on the car during start up, so it doesn't correct fueling based on incorrect data.....

Jonota

 

Yes I understand that. The point I am trying to make here is that pulling out 50% fuel at 800 rpm in PE mode is obviously having some affect during open loop because Im getting a lean code. I guess I should have stated before this adjustment Id see reading in the 800 mV range.

 

I think you might have another issue if some kind. PE is not used in open loop mode.

I dont understand how you are getting a lean code based on O2's in open loop mode?
in OL mode the O2s are ignored because they are not up to operating temp yet.

 

Well, I assume it was open loop since I was only 1 mile away from my house when this code appeared. Maybe I am mistaken. Ill check into this further tomorrow.. but you make a good point.

 

That was exactly my point, your open loop configuration ignores the O2's entirely. The purpose of open loop is to serve as a temporary until you get into closed loop. Getting a lean code I believe is the result of a blm pegging at 108 or 160 and the integrator exceeding 108 or 160(respectively).

As far as one mile, it depends on if the car was previously warm, or cold, and how long it took you to drive that mile. I think I've seen my car get into closed loop within about a minute after it was already warm and I restarted it.

Jonota

 

You must have another issue as mentioned, PE shouldn't effect anything at idle, you don't get into PE mode until 60% TPS at those RPMs I belive or something, forgot. Regardless, yeah lean code is when the PCM pegs at a sertain value to compensate with fuel but can't because the o2's (STFT) are still reading lean.

When I started playing around with closed loop lean idle iwth my big cam, which I did, after about 1 min of ideling after driving around warmed up, my SES comes on and she goes into open loop with a lean code, then I start driving and immediately she comes back to closed loop. Funny thing is when I come to a stop in closed loop at idle the PCM can't compensate because of my set integrator values, my o2's read about 200mv then PCM throws code and goes to open loop but I have my open loop set to lean aswell LOL so the o2's stay around 200 if not lower in open loop lol.

Matt.