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View Full Version : What would make my 93 1.5vtec Civic run so rich?


BlueBalloonatic
Mar 25, 2011, 10:18 PM
Hi all

Anyone have any suggestions as to what could cause the following?

If I roll down a hill in gear (she's a manual) then the CEL will come on reporting error code 41 (LAF Sensor) if I roll down the hill in neutral then she's fine.

Going by the black on the pipe at the rear I would say that she is running rich a lot of the time, there are a couple of other abnormalities that might be related... if I am stopped on a hill the tickover is about 700, as soon as I drop the hand brake and I roll forward the revs climb to about 1100.

I've cleaned filters, replaced plugs, checked the timing etc and I am at a loss.

The obvious answer is to replace the sensor but it is the 5wire version (that costs an arm and a leg) and I suspect that it is reporting the mixture being out range rather the sensor being faulty (same error code for both).

The car is stock standard and still doing about 35mpg around town, but it can't be good for the car to be running like that...

ANY help/suggestions will be gratefully received.

TxGreaseMonkey
Mar 26, 2011, 05:04 AM
Go with the obvious and replace the Oxygen Sensor (Denso only):

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563.html#post223376

Shop online for a deal.