993 obd1 varioram stalling issues

[Leslie SG]

Hi Steve, not sure you remember me but I used to be semi active on Rennlist as 'leslie'. I have recently got myself a manual 993 c2 as a daily driver. As the title suggests, it likes to stall when cold, when cold and the a/c is turned on and even sometimes when warm after driving around pretty much the whole day!

The way in which it stalls is pretty quick. Driving around on throttle or even off throttle is fine as long as I leave the clutch engaged. But once I come off the clutch, it revs fall and it just dies.

In terms of what hardware I have, this engine was rebuilt around 8k miles ago (mileage at that point was 47k miles) with varioram (the car is a early 1994 manufacture, RHD car). It has OBD1 and the airbox is a non factory standard one.

I had the throttle sensor cleaned out but this has not removed the problem. I was told by my local mechanic to get a new chip programmed to idle at a higher RPM to sort out the problem.

Does his advice sound sensible? If so, could you do a chip for me?

Thanks for all your wise advice!

PS. We run on 98 octane petrol here in Singapore

[Leslie SG]

Forgot to add: I am running a stock chip.
Reading up a bit, think this is the root of my problem!

[Steve]

Hi Leslie,

I certainly do remember you!

Stalling can be a bit of a challenge to resolve on the OBD-I cars.

Any anomaly such as small vacuum leaks*, old oxy sensors, old plugs and wires, dirty and/or old Idle Stabilizer Valve, MAFS issues, etc all play a role here. Further,....those cone filters that people clamp onto the MAFS really disrupt airflow into those things which further exacerbates the problem. It takes close attention to all these little details to ensure that the car idles properly.

Once all this done, an adaptation using the Factory scan tool (Bosch Hammer or PST-2) really helps fix stalling. I can do a chip for you, however that won't fix anything if there are resident issues,.... .

If you get a chance, call me to discuss as this is a terribly complex issue.

*Many rubber/plastic parts in the intake system should always be replaced when the engine gets a valve job or a rebuild.

[Leslie SG]

Steve,

Thanks for the reply! Nuts, was hoping that the stalling was coming from the fact that the car has varioram fitted and it is running on a factory standard chip.
So I guess plug and play is out of the question.

Given that we are here in Singapore and there is a time difference of 16 hours (we are ahead.. It is 1 am in Oregon while it is 5pm in Singapore as I write this),
I would need to coordinate this with my mechanic and call you.

What time suits for you? Could something like 9-930 am my time (5-530pm your time the previous day) work?

What number shall I call you at? 503 244 0990 is the correct number to get you at?

BR,

Leslie

[Steve]

Hi Leslie,

5-5:30PM my time is fine and thats the correct phone number to reach me.

Hopefully, we can get to the bottom of this problem and get resolution.

[Leslie SG]

Thanks for that Steve.
It is a couple of days away from Chinese New Year and much of this town shuts down during the period so I will get on the phone to you once the mechanic reopens his workshop. That is probably going to be on the week of Feb 18.
Hope that works? Speak then