Engine Stalling At Closed Loop

[Ginger pig 14]

Hi Guys,

It feels like I am re-living ground hog day......

So I recently completed a C service on the Esprit Turbo SE.

Had a few issues but overcame them... I have just one issue left!

As the title suggests; the car idles great for around 5 mins but then as soon as it goes to closed loop the engine starts to struggle before finally stalling.

No engine management lights illuminated until it finally stalls.

Please see attached File..... I cannot see anything untoward but I am hoping that someone might be able to cast their eyes over it and quickly ascertain what the problem could be.

Your help on this would be greatly appreciated!!!!

Cheers

Mark

091118a.csv

[Barrykearley 4,770]

Will it restart?? This is exactly what the IAC valve does on the old cavaliers 

[Ginger pig 14]

Thanks Barry,

yes restarts but only running for around 30 secs every time I restart it whilst warm.

cheers

mark

[johnpwalsh 1,213 4 Vehicles]

1 hour ago, Barrykearley said:

Will it restart?? This is exactly what the IAC valve does on the old cavaliers 

Don't tell me you had a Cavalier !!!!. Gob smacked, utterly astounded in fact. Almost as bad as if you were to say you had one of Andy's favorite Audi's.

[Barrykearley 4,770]

Ive had a cavalier - albeit only briefly. The IAC valve setup is exactly the same - and was a real problem on these cars as well

[sailorbob 126]

When the ecu determines closed loop operation is permitted the HEGO sensor shows a rich condition and the integrator reduces the fuel to try to get the HEGO sensor to switch lean. As the HEGO sensor remains indicating rich the integrator keeps on reducing the fuel to such a point that the engine stalls.

 

[Ginger pig 14]

Thanks Derek,

is the HEGO sensor the O2 sensor?

would this indicate that the O2 sensor is malfunctioning or could there be another reason for it not to be reading correctly (it was an engine out c service which meant all the exhaust system was dismantled and then refitted)?

Cheers

 

Mark

[sailorbob 126]

1 hour ago, Ginger pig said:

is the HEGO sensor the O2 sensor?

Yes.

Check the sensor and its wiring.

[Barrykearley 4,770]

If the O2 sensor has been contaminated with release agent or copperslip that really tends to ruin the things. The cable can burn against the exhaust or turbo. 

Are the O2 levels moving in freescan log? I can’t open it on an ipad

[Ginger pig 14]

The o2 levels looked to be ok up until point  of stalling.

[sailorbob 126]

The HEGO sensor values do not look OK. When HEGO value changes from its 'HEGO Initialisation Value' (aka KO2FF0) parameter value of 0.46 volts it jumps to over 1 volt and stays there until the engine is restarted (whereupon it gets reset). Because the sensor is continuously reporting a rich condition the ecu ends up pulling over 60% of the fuel thereby causing the stall.

[Clarky5150 74]

Listen to Sailorbob. This man knows his onions!

[Ginger pig 14]

Cheers guys,

new sensor then?

Mark

[Bibs 8,104 4 Vehicles]

Yup, @sailorbob is spot on as usual, Esprit legend!

Your O2 voltage looks like this...

whereas it should look like this...

[Ginger pig 14]

Wow!!!! That’s what I get for buying an cheaper after market version!!!!😩

[sailorbob 126]

Shortly after starting the engine when the HEGO sensor shows > 1 volt disconnect it and see if the voltage drops to around the 0.46 volts range. If it does then that would most likely indicate a sensor problem rather than a wiring short.

[Ginger pig 14]

Cheers Derek, that’s great advice!👍😀

At least I have a clear path now!

i’ll let You know once I have completed the process and hopefully have her MOT’d by next week!!!

thanks for all your help guys.👍😀

[Vulcan Grey 223 1 Vehicles]

Which O2 sensor did you have?

[tmusc 12]

Check to see if your map sensor is plugged in.

[Vanya 485]

@Ginger pigI had the same issue with my car when buying the aftermarket alternative from a well known supplier...mail the supplier and tell them about your experience with the part. The more of us that let them know the part isn't fit for purpose, the better. 

[Ginger pig 14]

Hi Chaps,

map sensor was plugged in. I have pulled out the o2 sensor and it looks pretty clean and unmolested. Is there any test that can be performed on the sensor at all?

Cheers

Mark

[Barrykearley 4,770]

They either work or don’t. Issues with these sensors are well documented on here.

the O2 voltage should sway all over the place just like Bibs post above. If it’s not doing that then it’s sensor or wiring at fault

[Ginger pig 14]

Evening gents,

tried cleaning the sensor and connections in the vein hope of reviving it... alas; it would appear that this unit is dead!!

other than SJ; are there any other alternatives which members would recommend?

cheers

mark

[Barrykearley 4,770]

 

[Chillidoggy 3,222]

Here’s a genuine Lotus job.