Smoky and idle problem

[SW_Rob]

Hi everyone

After a bit of help diagnosing a problem please:
Over the past couple of weeks the car has needed a bit of throttle to start and smokes until warm. It never used to smoke at all. It is not using any oil but does seem to be running quite rich. Today I started it and it seemed worse again idling at about 500 and then cutting out after 2-3 mins after start. It refused to start without quite a bit of throttle and was very smoky until warm when it idled higher but a little up and down.

Is this ECU? Idle? Sensor?

Thanks

Rob

[daddysumo]

Rob
You didn't say which model you have but Lambda sensor sounds like the one to check first I would say.

Steve

[SW_Rob]

m12 gto 2.5 (2002)

Original ECU (repaired by plans 8 months ago)

[joust]

Sounds like a lambda on the way out.

[SW_Rob]

I`ve got the build manual for the GTO-3, are the lambda sensors the same for the 2.5?

Cheers

Rob

[NobleGuy]

I've had another instance of smokiness on startup yesterday and noticed it hunts a little on idle.
Also noticed the lambda and CO (although they passed) were near the limit during the MOT on Saturday. Your description sounds like a similar (perhaps a bit worse) situation to mine.

[SW_Rob]

Is it true that the 2.5 only has one lambda sensor? Is it the same part no as the FAQ and how easy is it to replace?

Cheers

Rob

[NobleGuy]

I honestly don't know I'm afraid....
I thought there was one per exhaust outlet.

[gadgeroonie]

yes the 2.5 has only one lambda sensor on one side of the V6

the 2.5 engine is very sensitive to changes in afr - i guess its to do with the intake manifold design

[YellowShed]

gadgeroonie said:

yes the 2.5 has only one lambda sensor on one side of the V6

the 2.5 engine is very sensitive to changes in afr - i guess its to do with the intake manifold design

Only true for the non-MBE variety. Those that were originally on the MBE ECU and those that have been converted run twin lambdas.

Definitely sounds like the lambda is up the chute, from what you describe.

YellowShed

[SW_Rob]

Yeah, mine it the non-MBE (magneti marelli) early ECU.

Is the part number still the same though?

Rob

[joust]

Hunting is either lambda or a loose turbo/manifold joint letting air in.

J

[SimonJW]

Rob,

I'm currently having work done in that same area - see thread '2.5 ECU one of the 45'. I'm having after market ECU and new sensors fitted which does mean changing the wiring loom but I have no doubt it will be well worth it.

I won't know until next week to confirm the part numbers but the numbers on the Wiki are the same ones I gave to the garage fixing my car.

If you find out before hand drop me a line.

Cheers

Simon

PS I hope it is just your sensor. Check that it hasn't come loose as mine had.
Is your workshop manual available electronically? Would love a copy.

[SW_Rob]

If you PM me your email I`ll send the pdf across but its for the GTO-3 and M400 but quite a bit of stuff is transferable and better than nothing.

Where abouts is your lambda and which ecu did you go for?

[daddysumo]

YellowShed said:

gadgeroonie said:

yes the 2.5 has only one lambda sensor on one side of the V6

the 2.5 engine is very sensitive to changes in afr - i guess its to do with the intake manifold design

Only true for the non-MBE variety. Those that were originally on the MBE ECU and those that have been converted run twin lambdas.

Definitely sounds like the lambda is up the chute, from what you describe.

YellowShed

Trevor YHM.

Steve