Gents,

After surging idle problems and replacing the water pump my CEL turns on.
It doesn't turn as soon as the car is started. Usually it waits a usually less than 30 seconds but sometimes until you put the car in gear.
Jumping the blue plug the light reads four long flashes and one short flash. Code 41 from what I can tell is the O2 sensor. We replaced the O2 sensor but still am having the problem. We bought a Bosch from Autozone. I hear mixed commentary on the O2 sensors in hondas whether you need Denso or what not.
Struggled finding another thread about my same problem so I thought I'd post.
Thank you for your patience.

 

There are some resistance and continuity tests that you should do on the sensor to ensure that you didn't get a bad one out of the box.

In the Online Manuals thread in the DIY section, I posted a link to a 91 accord shop manual. Open to the 92 coupe manual, because it is much more organized and is basically the same setup as your 90 accord. Click on, Fuel and Emissions, then O2 sensor heater link.

That will give you the diagnostic tree for a code 41.

 

Did you get a universal O2 sensor where you use the old electrical plug?

 

Kris the sensor I got had the plug already attached.

PAhonda I tried the tests on the sensor we took out just to ensure we needed to replace it but was unsure if I was performing the test correctly. I'm also not positive my Voltometer is high impedance which is what I read I need.

Thanks for your suggestions. I'll look into the 92 coupe manual to see what it suggests! This forum is the best!

 

http://img139.imageshack.us/img139/3...acode41no7.jpg

 

Here's the upload.

So today I pulled the O2 sensor. Checked the A and B pins inside the connector according to PAhondas link and the online manual. It also said I need 10-40 ohms being read, however I'm only getting 4 ohms. I figured the sensor might be bad so I took it into Autozone we pulled a new one and tested it. It reads 4 ohms also! Confused we used their voltmeter and had VERY similar results. A fraction of an ohm difference (probably because the meters were zeroing differently.)

Suggestions? I put the original one back in since it's testing the same way so I now have the relatively new one out and plan to check a sensor at a local dealership to see if I get 10-40 ohms reading.

Reset ECU several times. I still don't get why the CEL goes off if after even 40 seconds of running the car you turn it off and back on. My mind is boggled.

Oh and strangely enough the universal sensor at autozone we pulled just for the heck of it and it read 9 ohms!

Still confused.

 

4 ohms is quite low for most consumer multi-meters (as far as measurement uncertainty). A bad heater normally goes to open-circuit, so it'll read overload or flashing (whatever your meter does when the leads aren't touching anything).

But it's strange that your meter & A-Z's meter agreed pretty well.

 

Gents,
I think I've identified more specifically when my CEL fires. It ONLY stays on as long as the car is in the high idle mode. So to me this says that maybe my air mixture is off for the time it's in fast idle (could that point us to the FITV?)

To be more precise out of the three stages of idle speed it goes through when warming up if I turn off and back on the car during the highest idle the CEL comes back on. If I wait even until exactly when the idle drops a bit NO CEL.

I really don't know what to do. I've taken the FITV apart before and adjusted the plunger. I'm unsure what else I can do or if it's even the problem.

Please let me know what you think.

 

Does anyone look at these posts once they're a month old? Perhaps I'll post it again on the general tech unless someone reads this and stops me!
Thanks for your help.

 

The FITV adds air until the engine gets to normal operating temperature, so I don't think that will be your problem. The IAC may be plugged with carbon and may need cleaned out.

Look for exhaust leaks and for a crack on the exhaust manifold.