Disconnecting MAF sensor - damage?

Disconnecting MAF sensor - damage?

Author
Discussion

mistergixer

Original Poster:

103 posts

159 months

Sunday 22nd April 2012
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Got a problem with the wife's Zafira A: hesitating, low on power, engine light on.

Checking the error codes gives a P0304 - misfire on cyl 4.

Replaced the plugs (which looked a bit knackered), did not resolve the issue.

If I disconnect the MAF sensor, the engine runs fine.

If I reconnect the MAF sensor, the problem returns.

This, to me, points to a faulty MAF sensor.

I've tried cleaning the sensor, but this hasn't resolved the issue. Nowhere is open today to get a replacement, and I'm going to be away all next week with work.

What are the potential problems that could be caused by leaving the MAF sensor disconnected for a week?


steveavxt

209 posts

200 months

Monday 23rd April 2012
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No ill effects. The ECU will use a known table of safe values if there are no readings from the MAF.

Crafty_

13,482 posts

207 months

Monday 23rd April 2012
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Steve is right - it'll just use a default value.

No expert but I can't see why a MAF would cause a misfire on a single cylinder. I'm gonna say coil pack. The only explanation I can give is that it will do this for everything, so unplugging the MAF is doing more than just making it use a default value for the MAF and that this is affecting the ignition side of things.

Either that or it is the MAF and the car is being made to run horrendously lean/rich - hence misfire/hesitancy. What is it like on fuel ? does it smell rich ? when you say the plugs were knackered what colour were they ?

VXRuss

1,547 posts

197 months

Friday 4th May 2012
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There is a breather hose under the cam cover, I bet that's in need of replacing.