Stalling and popping

[uai]

Hi Paul,
do you have threads for an A/F ratio meter in your headers?
I found it very helpful to diagnose to know whether I am lean or rich or whatelse.
If your ignition advance is still in the distributor and not in the MSD it would be an easy job to have a trial and error replacement of CDI and Coil.
But if you have the thread go for an A/F meter. I wouldn't recommend the Innovate Product as they are prone to failure (at least mine had a MTBF of less than one year)
Next time I'll probably buy zeitronix or stack.
Cheers

Uli

[PMNorris]

Hi Uli,
The advance is in the distributor. I don't have threads for an A/F meter on my SSI's, but the Zeitronix A/F sensor looks like a good idea. Mike (Had a 912 at the Early 911S registry Black Forest meeting had one installed and found it very useful). Swapping out the CDI and Coil to eliminate them also makes sense. I'll try replacing the jets over the weekend, but will probably take it back to the engine builder if that doesn't help.

[PMNorris]

Problem solved???

I have spent some time in the mancave today and have changed the idle jets from 55 to 60, put in new plugs (NGK BP5 ES. The previous ones which were fouled were NGK BR8ES, so much colder). i also replaced the batteries with new Varta 53 amp version. The previous tired batteries were 35 amps).
The car started instantly. After resetting the idle speed I went for a test blast in the Swiss mountains, up and over a pass to 1406M. Previously the idle speed was very erratiic, but now it is perfectly stable. I tried to cause the stalling issue, but it didnt stall once. I'm still runing the engine in, so i'm limited to 4k ish rpm. However, it now appears to be running perfectly. I'll try driving it to work next week, to test it in more normal driving conditions.
One more thing, the in line fuel filters that are supplied with the PMO kit have not been installed, so my problem could of been caused by dirt in the fuel. I will fit some.

Thanks for all your help and suggestions

Regards
Paul

[edmayo]

Good for you Paul, the 60 idle jets evidently solved the idle' hunting' problem, and the hotter plugs solved the sooting problem. Bpr8's are definitely too cold for street use. I do run the BP7ER in my street cars with no fouling problems.

[Merv]

Just reading this and the idle jets seemed the culprit from the first post (with or without hind sight). If still sotting then the air fuel mixture is too rich normally (assuming timing, points and valve clearances are set correctly).

[PMNorris]

Now i think the problem is isolated to tuning, i will take it to a local specialist for set up once i have completed the run in and changed the oil. There's a place fairly near me called bemani (www.bemani.ch) that look like they have a good set up and knowledge of early ingition and carburettors. I've not used them yet, but have been there for a visit.