So I bought a basic LED A/F meter, and hooked it up today. At idle cold it reads nothing. As it warms up a little it starts to rise up to show it leaning to the rich side of the gauge. Once it't warm even at idle, it cycles back and forth about 1 time a second which i understand to be normal only at about 1500 RPM. This is the first time i ever tried to use one of these things. Is this normal at Warm Idle?
I have a bit of a hesitation on acceleration between about 1000 and 2000 RPM. Timing, and idle are set to spec and it runs fantastic cold. Idle is smooth and I don't detect any kind of miss. Exhaust sounds pretty rattly when accelerating. 94 3.0 3vze 5-SPd
Did you use a wideband sensor, or the stock sensor?
Seems about right for the stock (narrowband) sensor..
The one on there is a Bosch universal 4 wire. I do not know how to tell the difference. I replaced it a couple years back so I don't have the information on it.
It was an autozone parking lot change and I probably went with the "Cheapest One" knowing me
Did you use a wideband sensor, or the stock sensor?
Seems about right for the stock (narrowband) sensor..
The one on there is a Bosch universal 4 wire. I do not know how to tell the difference. I replaced it a couple years back so I don't have the information on it.
It was an autozone parking lot change and I probably went with the "Cheapest One" knowing me
Uh-oh.
You may have just discovered the source of your miss. Apparently the Bosch O2 sensors are shorter than the factory (NGK or NipponDenso) unit, and don't stick far enough into the exhaust stream to get a good reading. A bad reading there would throw the whole mixture off, especially once the engine warms up and goes into open-loop (or closed, I forget which is warm/cold) mode.
Spark plugs are the same story, these motors just don't like the Bosch stuff for whatever reason.
NGK and ND are the factory parts, and not that expensive to replace. If your coil/igniter doesn't solve the problem, I'd look here next.
Good luck
My Truck: 1987 XtraCab DLX 22R 4WD 5 Speed Manual -------------------- "Speed has never killed anyone. Suddenly becoming stationary, that's what gets you." -Jeremy Clarkson
Put factory original parts in it... It's well known that a number of aftermarket O2 sensors don't match the exact length of the factory O2 sensor and they aren't centered properly in the exhaust stream...
and I especially like NGK plugs.. excellent performance and one other thing that even the ND plugs don't have.. The threads of NGK plugs have a plating over the steel base metal that keeps them from seizing up or making the horrible, scary squalking noises as you try to remove them after they have been in the head for a long time.... especially important in aluminum heads...
Can someone post a pic of an exact OEM O2 Sensor and maybe some dimensions? I actually do believe I have a super lean burn problem. I have more trouble shooting in another thread i wont get into here. But since this is on gauge and sensors I'll keep on topic!
I just installed a Denso brand direct fit. Here is a picture of what I just took out vs. what I just put in. Obviously there is a huge design difference. But I also discovered that the old one was not installed correctly. It went like this:
The heat shield is molded in such a way that it could never have gotten a good seal in this configuration. And there is carbon deposits to prove it. When I changed this before I was in a hurry in an AutoZone parking lot. The one in there also was in wrong. So if you guys say that these after markets are already too short, i imagine the 2 extra layers of stuff only reduced it by another 1/4" that is a lot. We shall see how it goes from here.. I will keep yall posted.
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