TheGoodSon

Hello CL faithful. Thank you for all the good reading in last few months. I found the ECM mega thread was most helpful. I come to you now - as I have hit a wall.

Car is my elderly veteran father's 92' ES300. He has loved it dearly for @ 20 years, but I fear it has been in the hands of some unscrupulous repair people and it is in rough shape. So I jumped in and we brought it back from a random garage who could not identify why two cylinders were not firing. I brought it to Premier in Tempe AZ and they sorted out the wiring mess and pointed at the ECM. I researched that crazy ECM business and sent it off to foreignecurepair.com in Texas and while their price was $250, they moved on it quick. When I plugged it in, I got two cylinders back and the car seems to be running great. Shifting better too.

So, the final hurdle is getting this car past emissions. First run was not good. HC (1.0 std) was 2.98. The CO (12 std) was 57.

I enrolled him in state cost help program and then took it to one of their approved garages. That garage quoted $2000 to change oxygen sensors and cat (was blue). While state would pick up $900 of that, garage was hedging and saying - "after that we can figure out what is up". Not exactly the vote of confidence I expected after $2k spent. Note that State only pays their share AFTER it passes. I strongly suspect this garage did not want to work on my dad's car at all. It was easier to take the $75 diagnostic fee, quote high and save the busy bays for bigger fish.

So, I bought a Walker Cat and replaced that pretty easy. I also replaced the oxygen sensors - with that last one being kind of a bear. Went to emission test and new numbers are HC = 2.34 and CO = 37. There was improvement.. but not enough.

Ideas? What can I replace next? Should I have done some ECM reset procedure after I did sensors / cat change? This car passed emissions two years ago and had $1k worth of injector / fuel work done just before that. Would love to sell it and move on, but my dad is going to have trouble learning a different car. The car doesn't even get used much -like 500 miles per year. Mostly grocery store trips.

Please help - if you can. I apologize if this has been covered before, but I honestly read hours and hours of posts and did not find anything on point. Thank you for your time.

LeX2K

3VZ-FE is a relatively simple engine. Best you can do is replace the spark plug wires (OEM or NGK), plugs (from a dealer to avoid fakes) change the air filter, set the ignition timing to exact spec. Injector failure or any issues at all with them is incredibly rare. What brand of O2 sensors were used?

How many miles? The ECU doesn't need to (or can) learn anything outside of idle speed which takes a few minutes.

Arsenii

Hello,

What brand O2 sensors did you get, and which ones did you replace?

What cat did you replace? My 2000 ES300 is from Arizona and qualifies as a California emissions vehicle, it is equipped with Three-Way catalyst system, which includes one Main cat, and two Secondary ones per each bank, I was wondering if yours is the same way..

Go to the nearest car parts store, they can rent you a scan tool for free, just find one that can display Engine Live Data. Check your Fuel Trims, as well as O2 and MAF sensor readings - in short, Fuel Trims should be as close to 0% as possible, if they are more than 10% out in either way, it would be time to look for a cause. You should still have older style O2 sensors, so you should see readings fluctuate from about 0.1-0.2V to 0.8-0.9V, as a quick test, floor the gas from idle and watch the readings immediately spike to Rich side and come back down to normal mode, if not, the sensor may need to be replaced. MAF sensor should show about 3-4.5 g/sec.

I am not sure about Walker, but there are aftermarket that manage to make things even worse, so you need to watch out for that, especially considering prices for platinum these days. See if you can find used OEM cats off of some low mileage car, that will be the best option.

Hope this helps and best of luck!

LeX2K

Car is too old for live data, OBD-I only. Pretty sure there is only one catalytic converter, in California it's just a more robust unit. But I've never seen a Cali spec 3VZ.

Arsenii

Huh, I actually thought it was a 1995 for some reason..

With that, it's still possible to get at least some live data even out of the OBD-1 protocol, how to make a tool and the process of reading the data is described here. There is only one major flaw - one second lag between each refresh, limitation of an older standard.

Hope this helps and best of luck!