kford1040

All,

What causes extremely high calculated load and also makes the MAF jump all over the place.
I'm in DC metro and did notice this car has Calif. emissions.
Other than the overdrive being shut off, which I know can be caused by a sensor malfunction, which retards the timing. This car sounds better and is getting better gas mileage than before.

I did have a battery problem earlier this year in that it 'leaked' so bad it had to be replaced before it expired. The connectors had a lot of 'corrosion' and I don't know if there is anything else that would affect the circuitry.

Sorry if this is a bit disjointed. I'm so frustrated since the readings are all over the place. (see below.

Thanks,

Kimberly

Background:

As a quick run down My lean bank 0171 error code is gone and I have replaced the spark plugs; the B2 01 AF Sensor and- the B1 01 was done last summer (2 times - the mechanic 'said' he used a Denso. I had cleaned the MAF but was getting weird A/F readings still so put a new one in and that was worse so put the old one back in.

My gas mileage is great until the overdrive retards (22 that never happened before) only thing I can see is that i have these crazy spikes with either MAF and the calculated load has hit as high as 61% yesterday when the CEL went on doing 17 MPH.
ST FTRM 1 % 1.6
LT FTRM 1 % 0.8
ST FTRM 2 % -.08
LT FTRM 2 % 3.9

That was yesterday on my way home.

This morning it wouldn't go into overdrive on my way in so I put the old MAF Back in since it was jumping as high as 5.2 lb/m with the new one (which I think is 39.39 gm/sec?) though it was better there were still problems.

After I switched the MAF I saw what stayed as a pretty odd constant in the ST percentage while i was driving and prior to the sensor change yesterday it was the LT ratios that were in the 23-30 range. since this doesn't make sense to me maybe someone can help.

I was at 2310 RPMs
IAT 59
ST FTRM 1 % 19.5 (constant no flux while doing 50-57mph)
LT FTRM 1 % 0
ST FTRM 2 % 19.5 (constant no flux at 50-57mph)
LT FTRM 2 % 0

hypervish

Where did you buy the new MAF from, is it OE?

kford1040

I got the MAF from Carquest. It's an OEM - came in a Toyota box. I know for sure the A/F sensor that I put on is the correct one 4xx? - 9009 is the portion that comes to mind. But I don't really know about the one the garage put on in the spring and then replaced again in the summer... They said it was a Denso...

code58

I think the proper Denso # should be 234-9009 for the A/F sensor. Are the sensors you have in now the ones you put in or the ones the mechanic put in? Being a Ca. car, the listing is different for the other states. It gets a little confusing because you may or may not find RX's that were delivered in other states showing an A/F ratio sensor OR an OXYGEN sensor. The A/F ratio sensors were just beginning to be used when the RX 1st came out, and as you probably know, the 2 are VERY much different and cannot be interchanged. I ordered 2 for my DIL's RX from an E-Bay vendor in Florida and they swore they are the correct thing for B1S1 and B2S1 and even though they were informed it is a Ca. car, they were incorrect (oxy. sensors) and would not take them back. They are Denso parts.

artbuc

Roger, I am pretty sure that the RX takes only 234-9009 for the upstream sensors whether it is a CA car or not. On my 99 Avalon, which has the same engine w/o VVTi, upstream sensors ARE A/F for CA but regular O2 for non-CA cars. I know for sure that my 99 RX was not a CA car and it did take 234-9009 for upstream.

code58

Art, it's probably more of a parts book thing than real world. Most parts books listed Ca. separately as A/F and other states as O2 on the RX. They contended that the O2 were the correct sensors even though they knew it was a Ca. birthed car. I have my own doubts that there were any U.S. RX's that had upstream O2 sensors. Wouldn't be the 1st. time a parts book was wrong would it? Course from the errors I've seen in the factory CD manual, that information could have come directly from Toyota. The history of when different cars and trucks went to A/F sensors is pretty strung out, not even all of any one make getting them at the same time. As you can see from what you said about the Avalon, they were PHASING in the A/F, not a very clearly defined demarcation line.

kford1040

I put the correct A/F sensor in B201 the Denso 234-9009. what I don't know is what the mechanic put in. I was always told that an Oxygen sensor had been replaced. then that the Oxygen sensor went bad several months later, which IMO caused more problems with the continued 0171 error.

That said I just didn't know if the CA emissions mattered.

Looking at the live reader the readings just jump all over the place and don't make sense.

The calculated load is way too high 30-60% and the new OEM MAF readings I've seen go up to 7.1lb/min, which i am pretty sure is bad. But then everything will be fine and it's within range.

I think there's a short in the circuit but I don't know how to track that down and I get told there's either no code or replace a knock sensor, which I get go bad but something ELSE is tripping the 0325 code AND my car can run great some of the time with better gas mileage than it's had before even with the light on.

Whatever it's doing to retard the overdrive is intermittent and doesn't record an event, so I need to get a different reader that can capture the information so I can put them on paper.

I tried to change the IACV the other night but could not get the screws off. I will try again today and see if I can track down a different MAF sensor.

artbuc

7.1 lbs/min = 53.7 gms/sec. At idle you should have about 3 gms/sec and maybe 3-4x that at 2500rpm (no-load). The very first thing I would do is to confirm what you have in B1S1. If it isn't a Denso 234-9009, make it one. How did you get a Toyota MAF from Carquest? Carquest sells Denso Aftermarket but not factory, at least as far as I know. Even so, getting parts these days is tricky because so many dishonest folks out there return used and/or defective parts and sometimes you get stuck with them. I know this from first hand experience. IOW, I would not assume your MAF is good.

code58

Quote:

I tried to change the IACV the other night but could not get the screws off.

Been there, done that. The way to get the (very soft) screws out of the IACV is with a set of needle nose vise grips, clamped nice and tight and a "snap" to loosen the screws. The other way is with and "impact driver". That is the tool that takes different sizes of screw driver short bits. You use the correct size bit (I believe it's a #3 Phillips) and when inserted firmly in the screw, hit it a fairly good blow on the end. It has a spiral inside that tends to loosen it when impacted. They are VERY effective and can be purchased pretty cheap from Harbor Freight. Get the smaller size, not the largest. The SOFT Japanese screws and bolts tend to"'grab" and come loose with a "snap". The problem is the "grabbing" of the soft screws and the fact that many people mistakenly use a # 2 instead of a # 3 Phillips.

kford1040

To be honest I had a hard time tracking down a new MAF. Two dealerships didn't even have them and I'm not even sure mine was bad to begin with.
I stopped at Carquest since I saw on the Denso site that they carried the right part. It wasn't in stock and had to ordered for pick up later that day - when I went and picked it up I was suprised it was in a toyota box and the part was sealed.
I think the bottom line is the knock sensors just have to be replaced and regardless of what my logic is that is the cause of the problems not the other way around....I have almost 150k on the car and put 60k on it myself only using regular gas, so I don't think I should be complaining....though I know I have been....