coach928

i'm a new 1986 928 owner, and I built my own adjustment tool and Blinkr per the instructions. Blinkr only blinks at MAF pot setting of 2 ohms. When I temporarily adjust MAF to 380 ohms, startup from cold is wild until O2 sensor warms up.

Is MAF pot setting of 2 ohms a sign of a failing MAF or O2 sensor? Could this be related to my high NO emissions?

I started a related thread with more details:
https://rennlist.com/forums/928-foru...on-blinkr.html

John Speake

A setting of 2 ohms would give a very weak mixture - if the MAF is aged it would be even weaker.

Aged MAFs would need more pot resistance.

Sounds like the measurement system is the problem.

coach928

The measurement system in the MAF is the problem? or elsewhere?

The MAF could very well be "aged".

Thank you for the assistance,
John

John Speake

The fact that the car generally runs better with the pot at 386 ohms even when the blinker says it is wrong, suggests a problem with the measurement.

Have you tried disconnecting the O2 sensor and adjusting the pot so the engine idles well and responds OK to the throttle ?

Hi NOX suggests a weak mixture as per our email conversation.

coach928

I made the Blinkr after our email conversation. The car runs well and idles well with MAF pot at 2 ohms, not so well at 380 ohms. I will try disconnecting O2 sensor and adjusting to confirm.

John Speake

Have you checked the basics like fuel pressure and engine vacuum at idle ?

The problem could be a MAF problem, they can suffer a form of thermal runaway where the output will be higher than it should be. This enriches the mixture and would force you to turn down the pot to compensate.