Wonky idle after restart

[J4CKO]

My S2 seems to be runnign fine, starts up and goes, pulls well enough, but if I go somewhere and then restart it the idle goes mental, i.e. dropping below idle and then cuts out, it then restarts and then seems to be ok.

I was thinking fuel pressure regulator, dont know why but seems a reasonable assumption, I have changed the DME relay.

Any suggestions ?

 

[J4CKO]

Meant Idle control valve.

 

[J4CKO]

ok, got the valve off, how do you clean it ?

 

[944 man]

Carb cleaner Id guess. There are plenty of threads on the American boards, if you can bear their grating whining, arrogance and bullsh*t!

http://www.google.co.uk/search?q=clean+isv+944&sourceid=ie7&rls=com.microsoft:en-gb:IE-Address&ie=&oe=&redir_esc=&ei=IPmgUdDXO4az0QWq-YC4Cw

 

[J4CKO]

Lol, its in bits, had to drill one of the allen key bolts out as was tight and I rounded it off, it didnt seem gunked up, an hoping it is that as I am sick of it going into shudder mode.

 

[Mike_Pollock]

I'd go for FPR - very similar symptoms to my old Lancia HPE iE with the same Bosch kit.

 

[944 man]

FPR is never wasted money.

 

[ChasR]

ORIGINAL: 944 man

FPR is never waster money.

Not with recent times I must say and the number of people it seems to affect.

 

[J4CKO]

Think I will put it back together this afternoon and see how it goes, if not cured will order a FPR, they are about £100 are they nit ?

 

[JamesO]

Maybe worth checking the coolant temp sensor with a multimeter before forking out for a new FPR. If the engine thinks its cold on restart it will run rich. Unlikely to cause it to cut out I would have thought but it is a free and easy check.

 

[Eldavo]

I'm about to replace my DME temp sensor as the car idles terribly when cold and cuts out but is fine when warmed up.

I checked the sensor with a multimeter and it was way out so pretty sure this will fix it.

When it fails it fails to "hot" meaning that the engine will run lean not rich, hence the cutting out.

 

[edh]

My s2 ran very rich when the dme temp sensor failed

 

[J4CKO]

Tested the temp sensor, seems ok, it was at about 250 on the multimeter and then went down to about 40 in hot water so that fits in with what I have read. Getting the isv back on is very fiddly !

 

[Eldavo]

Are we talking about the same sensor?

According to Clark's Garage the reading should be:


DME Temperature Sensor Resistances
15-30 °C (59-86 °F)
At 59 °F approximately 3.3 k-ohms
At 86 °F approximately 1.46 k-ohms

 

[J4CKO]

The one on the front of the block, blue socket ?

 

[JamesO]

Sounds about right IIRC for the coolant sensor (blue plug). The other sensor is in the AFM, it measures intake temperatures.
ETA, scrap that it sounds like the readings you would get from the sensor that feeds the gauge.