3.2 Carrera: lean @ 2500rpm

[MaRu]

I have a 1985 Euro 3.2 with 231 hp.
In summer it runs good but a little bumpy @ 2.5 k rpm. At cold temperatures it is nearly impossible to drive in this rpm range. It is very lean. I already changed the temperature sensor (twice), compared and messured everything but it just donīt worke the way it should. Any ideas what more I can do, or what I might have forgotten to check?
Many thanks,

Malte

[prschmn]

How do you know it's lean? Could try closing the bypass on the AFM to see.
3.2 AFMs are kinda notorious for being problematic.

[kuehl]

Wide Band 02 AFR Meter: buy, borrow a wide band 02 meter to verify AFR

Vacuum leaks: spaces enlarge when cold. Try spraying carb cleaner or starter fluid (be careful) around intakes flanges at heads, vacuum lines around back of motor, oil fill cap, etc, to see if condition improves.

AFM: Testing the AFM's Potentiometer

Other: fuel delivery; filter, injectors, FPR

And, DME Test Plan


Mark, nice engine work, don't know how you squeezed those 3.8's in there.

[MaRu]

I checked the mixture with an CO reader. I check for vaccum leaks,too. But I did when it was warmer outside so I should give it another try.

[stlrj]

It might be a good idea to clean your injectors:

https://www.youtube.com/watch?v=7aT4S1lIBAY

[larrym]

fwiw - have a similar (maybe ) problem with my new SW chip - it pings on light throttle tip-in - Steve says it is likely lean at steady throttle & the AFM wiper is a possible cause - i have not yet taken it apart to look/test

(i am NOT running an 02 sensor - also possible problem per Steve, tho that should make it go rich, not lean imho)

[manbridge 74]

Does the AFM look like it was previously opened?