22re ECM fueling strategy

[toyotaboy80]

Anyone know the fueling strategy? More specifically, how does the base fueling map compare to open loop vs closed loop fueling?

Is the base map = to open loop?
Are closed loop +/- trim values always less than open loop?

In open loop, is the fuel quantity always greater than the fuel quantity delivered by a lean trim value given by the O2 in closed loop? OR if in closed loop and 02 sensor is reading lean, does the ECM trim up to put more fuel in than the open loop map?

I guess an even more simple way of asking these questions, does closed loop use a different base map to +/- fuel than is used for open loop base map?

 

[gnob]

Yes. Closed loop is based on feedback of the o2.
Open loop will always be fat, as will WOT.

What are you after exactly?

 

[gnob]

The fuel trim according to the Toyota efi book is +-5. It doesn't really go into map graphing.

 

[toyotaboy80]

Basically my motor is getting poor gas mileage and smells rich. No cat...smells richer than usual. The Vf ecm value is reading 5v in part throttle or idle. Which means the ECM is trimming up fuel to it's max possible fueling capability while in closed loop. Because it's trimming up fuel, it means the O2 is reading lean and telling the ECM to dump in max trim in closed loop. When I go WOT or hammer down enough, the Vf will drop to 0v which means it starts fueling based on open loop. If I open up the throttle to 3000rpm the Vf still reads 5v and when it returns to idle the Vf will drop to 1v(trim down fuel) settle at 2.5v(optimal) for a bit, then go back to a 5v reading after 30 seconds or so.

I want to know if open loop is more fuel than a max "trim up" fuel in closed loop. Meaning if I unplugged the o2... it would fuel even more or would it lean up a bit because that's less fuel than max trim closed loop.

Because it smells rich and is getting poor mileage, I don't necessarily think the ECM needs to be at max trim value. I'm trying to figure out if the o2 sensor is the issue, or if the problem lies somewhere else causing erratic readings/fueling.

 

[gnob]

Not sure that is going to get you where youre going.
I recommend getting to a exhaust gas machine.
Otherwise you can see if you are trimming sorta properly by unplugging the o2, dmm to sample o2 output. Now take a wire and hook to the signal going to the computer. Use yourself as a resistor by holding the sample wire in one hand and touch the pos or neg battery terminal WITH YOUR OTHER HAND. this sendz a weak signal to the ecu simulating the o2. Read o2 to see if it responds appropriately.
Ive seen o2 signals get grounded out by bad repairs or chaffing which in turn causes lean condition.

 

[Toast]

What kind of fuel mileage are you guys getting? What’s normal for the 22re anyway? It’s not like we can gingerly accelerate to get around, Gotta give these gutless turds some throttle. I get 15 and do mostly in town driving. I usually drive it like I stole it but that’s the only way to not get passed by Prius drivers...

 

[gnob]

My stock 86 4R on 235/75s got 19-21 normally. 17 or less when driving like an așš