Mis-fire and won't tick-over

[glynherron]

Hi guys,

I need some help and fast !!

My Vectra's cambelt snapped taking out the valves so is off the road!

I have been using my esprit but on the way home developed a misfire. It got to the point just as i arrived home that it wouldn't pull on part throttle.

Doing a freescan (not much knowledge here), I noticed that initially when started the IAC count was 130 ish, and during the next few seconds decreases. The the engine starts to get rough, hunting etc and the IAC count starts to rise, slowly at first, and then rapidly as the tickover gets worse. This takes about 6 seconds after which time the engine stalls.

I have tried to keep it running, by blipping the throttle, and sounds like a fule problem?

When the misfire started on the way home it registered a fault code of 44, but after stopping and restarting, the light has not com on since.

Where do I start? (I think I had better get walking to work now !!)

Thanks guys, and look forward to your replies.

Glyn

Edited January 18, 2006 by glynherron

[Dermot]

Glyn,

IAC will start high (170) and work its way down to about 50.

Code 44 is lambda sensor error, do a log and can check if you lambda sensor has gone, that would cause bad idle and even stall.

Dermot

[glynherron]

Glyn,

IAC will start high (170) and work its way down to about 50. 

Code 44 is lambda sensor error,  do a log and can check if you lambda sensor has gone,  that would cause bad idle and even stall.

Dermot

<{POST_SNAPBACK}>

Hi Dermot,

I will reply to your email !!

the lambda sensor is OK - the volts jump about as they should.

I'm sure its one fault that is causing the misfire and the poor ! tickover.

Any other ideas where to look?

Glyn

[glynherron]

Update - the lambda sensor fluctuates between 0.138 and 0.214, which is not the spec stated in the freescan manual.

Would this cause the misfire as well, I would have thought that the air/fuel mixture would have to be way off to cause a misfire? I'm sure that someone will correct me! Its the only was to learn.

The sensor was bought last June (05), and is a generic sensor that has to be spliced into the wiring harness. Could this be why it only cost

[pitstoppete]

lambda could be an intermittent problem, going bad, then sorting itself?

is the o2 volts fluctuating the full range on freescan?

try a ecu reset?

add...

my lambda goes between 0.1 ish to 0.9 ish

new generic one from"just lambda" (do a search) was 38

Edited January 18, 2006 by pitstoppete

[pitstoppete]

lambda could be an intermittent problem, going bad, then sorting itself?

is the o2 volts fluctuating the full range on freescan?

try a ecu reset?

add...

my lambda goes between 0.1 ish to 0.9 ish

new generic one from"just lambda" (do a search) was 38

[Dermot]

Glyn,

If the lambda sensor only swings between 0.138 and 0.214 once warmed up at idle you have found you problem.

Dermo

[glynherron]

Glyn,

If the lambda sensor only swings between 0.138 and 0.214 once warmed up at idle you have found you problem. 

Dermo

<{POST_SNAPBACK}>

Brilliant and lets hope so.

I reset the ECU and then I gambled and took it for a run to warm up fully, taking a route that didn't need tickover. When warm tickover is fine, just the misfire on anything above tickover.

I'll do what pitstoppete suggested and solder the wires. I joined them with the butt splice connectors supplied with the sensor.

Do you think its worth paying the extra for the part that Pete has fitted or

[Joey]

Not know much about the Esprit yet, I can say that you should never butt splice wires going to the O2 sensor.... always solder them or get the correct connector...

Since a butt splice will not get the best contacts, and can cause some corrosion it will not only cause it not to get proper signal, but it can also destroy the O2 sensor....

I would solder them first and hope it is still good.

[glynherron]

Not know much about the Esprit yet, I can say that you should never butt splice wires going to the O2 sensor.... always solder them or get the correct connector...

Since a butt splice will not get the best contacts, and can cause some corrosion it will not only cause it not to get proper signal, but it can also destroy the O2 sensor....

I would solder them first and hope it is still good.

<{POST_SNAPBACK}>

Sorry Joey, I saw your post too late to try it out.

I bought and fitted a sensor, I haven't had the chance to Freescan her.

The major misfire has gone, but still coughs and spluters; leaves a cloud of ? when setting off (can't make out the colour - night time), and when accelerating feels like either the ignition has been turned off or running out of juice.

I will post later when I have scanned her, but no engine check light lit.

TTFN

Glyn