Lean Cold Start Problem

[swingtan]

Hi All,

I'm hoping someone here can help out with this one. I have a problem very similar to this..... http://forum.efilive.com/showthread....ght=cold+start except that it only occurs for 8 to 9 seconds for me.

The car is an L76 Holden, with the E38 PCM and is currently running a MAF-less tune. When it first went MAF-less, it didn't have the problem, but had a very rich idle when warm. After some auto VE work, the warm idle has been fixed, but I now have this cold start lean out problem.

I've attached a log segment showing how the measured AFR's start off well, but then lean out to 20:1. After 8 seconds from start, the AFR's come down to the 14 range and all is fine, but for the first 8 seconds the car runs very rough and sometimes stalls.

Here's what I've thought about....

• Given is really only cold start, it must be something to do with OL fueling.
• I've looked at B0141 to B0148 and tried altering settings to richen up the fuel on cold starts, but there has been minimal effect.
• The 8 second time had me thinking it may have something to do with B1832, but again this seems to have little effect on the problem.

I guess I could try altering the VE table to richen it back up, but that's not the way it should be done. Any ideas on what to look for here ?

Simon.