'911 Chips'...
Well it was a pretty easy DIY and I must say the car has not stalled for the last 2 days. BUT....it does still do the surging thing now and then, and the idle is at 900rpm instead of 700. So it sounds like it is reving a little high but I guess I'll get used to that.
It is a real relief to be rid of the stalling issue though, it quit on me a couple of times in the middle of a turn thru an intersection when the car in front of me suddenly slowed...made it hard to complete the turn with no power steering and trying to defeat the immobilizer and re-start all at the same time. Gulp.
The DME may be still in the 'learning' curve with the new chip, but I have followed the instructions to the letter so far. Think I need one more 'cold start' to make the 3 required. Gave it the 3 minute ign only, start and idle for 3 minutes, shut off and restart, but only drove it twice since then.
We'll see if it gets any better. I'm sure the idle is there to stay, but it would be nice if the surging went away altogether...
The chip I removed has the following information on it:
AutoThority. Perf Eng
POR.01.993.200 ser 10038
1995 CARB EO# D-228-1
Hope that helps. I liked the way the engine performed with that chip with the exception of the stalling. I was getting pretty good at 'heel and toe' to prevent it but it wasn't the easiest routine in city traffic.
Jim
The cable connector is a bit of a trick though, it has a metal 'lock down lever' that you need to get your finger nail under and lift and pivot out of the way to release the multi pin cable connector to the Motronic box. One end of the connector goes 'under' a plastic bit on the box itself then the 'pivoting' lever' folds down and hold the connecter in place. I knelt on the floor beside the door sill and reached under the seat from the front with my left arm, and from behind with my right arm, and managed to get the connector back on the box by 'feel'...
Jim
So it's a 200 Autothority chip (same as what I have).
The DME should have a number on it. It often ends in 163 or could be another number. That last 3=digit number is what matters.
I'm not keen on pulling that out again if I don't have to...would the number be anywhere else?
Jim
But... here's a question. How did 911 Chips (that's Steve Wong, I assume?) know what DME you had to mate their chip to it? If I understand correctly the chip is DME-specific. In other words a chip made for 163 DME will not work right with 674 DME, etc.
PS. I had the same feeling with LFW in my previous 993. It was nice but stalling made it completely street-unfriendly and sometimes downright scary.
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Car runs perfectly now.
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And 'barvarian06'...sorry but what is a MAF? I removed and cleaned the ISV ( idle stabilization valve ) the day after I got home with the car. Made little or no difference. Also checked the 'floor mat' location, i.e. riding up the accelerator pedal and preventing the full movement necessary for the ECU to function normally...again, no change.
Jim
Mike: PM sent re chip
On the idle - I am certain that the car will idle at 900 or higher. I think that's the major adjustment in the chip to prevent stalling (the idle dropping way low and can't catch up). Another way of accomplishing this is have John D. adjust your ICV

Drove the car this morning and starting cold it was fine, no surging. But the second start with a warm engine was horrible, the surging was so intense, like going up to 1800rpm, falling to 200rpm, back up, down, etc, I finally stopped it with the gas pedal. The next time I let it go to see how many up/down cycles it would complete before it either stalled or settled down. Eight. Seemed long watching that big wooop up, and rattle at the bottom just short of stalling.
Not happy. I'll be in touch with Steve Wong, '911 Chips' later today. In the meantime I might put the AutoThority Chip back in. At least I can heal and toe it, but really, there should be a solution for this.
I completely removed the MAF, clean as a whistle. The K & N air filter was a little corrupt but a gentle brushing and tapping, with compressed air to help cleaned it up nicely. Thanks for the tip on that, at least I know how to remove it now, oh, and the ISV was still shinny.
Jim
My car does some minor idle surging when first started cold sometimes. It settles down very quickly and does not do it past initial warm-up.
PS. Thanks for the pic!


