ive changed the o2 sensor. its reading 13.8 ohms which is good (10-20). ne other suggestions of what i might be before i take it to a shop?

 

.

 

up.

 

Code 1 is for the oxygen measurement. That's different from the preheater.

Measuring resistance across the heating element of the sensor is for code 41.

To check the actual oxygen measurement you can use an oscilloscope (best) or an analog voltmeter to watch how fast the signal swings back & forth while idling.

Have you done any other checks or measurements or modifications??

 

nopes. can u give me a lil more detail on how to go bout checkin it

 

You can back-pin the signal wire, to measure it while it's still connected & running.

The reading should swing between about 0.1 & 0.9 volts. The voltage isn't so important, but you should see it swing quickly. I guess 10 times a second or something like that. One of the most popular ways for a sensor to go bad is that it gets sluggish. Then it only swings a couple times a second or slower.

Most digital DMMs are difficult to read this way. They only update their display a couple times per second anyway. With an old-school analog meter you can watch the needle quivering.

You've already changed out the sensor. So what would cause it to go bad again so quickly? Silicon is a strong poison for the sensing element. Used any RTV anywhere lately? Or maybe some slimy stuff to make your black rubber hoses clean & shiny?

 

well i did install a headgasket upside down so oil splashed all over the firewall n most likely onto the sensor.

 

OK, maybe that's it. The O2 sensor actually measures difference between inside & outside the exhaust pipe. So there has to be some kind of vent where it can see the surrounding air.

If you look at the sensor, the top part that's made of sheet metal has little louvers in it...

 

uh i got lost there.

 

Sorry...

If you get gunk all over the outside of the sensor, it gets messed up.

I thought you got oil all over the outside of the new sensor. But now I get your PM saying that you put in the new sensor AFTER the big oil mess.

So I don't really know why the new sensor would go bad so soon. ???

 

up for a solution.

 

school is almost out!

 

So do you clear the code 1 and it keeps coming back?

Can you think of anything that happened since you put in the new sensor?

 

i took off head. resurfaced/3 angle valve job/port n polish then slapped it back on w/victor x mani. tried it n found out the gasket was upside down. so bought new one n installed correctly n i had cel 1 & 14 and a surging idle. finally figured out the i had my switches mismatched n cleared the cel 14 n the surgin idle. now i just have a cel 1 n bad idle at 2k.

unplug neg cable to clear n it keeps comin back. ive tried everything for the high idle (iacv & fitv & vac lines) so im thinkin it has somethin to do w/cel 1?

 

.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shifts &raquo;</TD></TR><TR><TD CLASS="quote">... so im thinkin it has somethin to do w/cel 1?</TD></TR></TABLE>Well sure, CEL error code 1 is always the oxygen measurement (not the preheater).

You could check for loose, dirty, corroded connections anywhere in the O2 measurement circuit. I thought I still had a list of ECU pinouts, but I can't find it now. You could probably search around here for that...

You've got 2 wires from the O2 sensor back to the ECU (besides the 2 preheater wires). The signal wire might be shielded, so be aware of that if you splice anything with that wire. The signal-ground wire from the sensor goes to the ECU separate from any general-purpose ground.

It's an oddball chance thing, but I've even heard of people who found bent pins in the wiring harness at the ECU. They don't make contact with the proper terminal in the ECU, even tho the big plug is plugged in tight.