jakfrost

I got down on my hands and knees yesterday and did the 'braille' method of removing the DME box from under the drivers seat, opened it up and pulled the 'Auto-Authority' chip, replacing it with the '911 Chips' 52 pin, LWF, 91 octane chip, 'guaranteed to eliminate the stalling problems associated with the LWF/clutch modification.

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...

nile13

What DME do you have an what's the Autothority chip's number? I'm trying to figure out my own situation here.

BTW, any advise on pulling DME box without removing the seat?

jakfrost

Well I can't say I know the name of the DME but the box says Motronic on the outside...if that is any help, but I suspect they all say that.

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

jakfrost

Oh, sorry, the second part of your question...well since the car came to me with the AutoThority chip installed I didn't have to mess with any 'shear bolts' and just used a deep 10mm socket to remove the 2 nuts, one on either side of the Motronic box under the seat.
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

nile13

Thanks,. 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.

jakfrost

OK, understood, sorry but it will have to wait till I get home tomorrow, doesn't the DME reside in the box that I just described as 'a little bit tricky to get in and out' ?
I'm not keen on pulling that out again if I don't have to...would the number be anywhere else?

Jim

nile13

Jim, the number is on top of the DME box. If you can lift the seat to its highest position and stick a cell phone in there, it's usually possible to take a picture of the label on top of DME box. No hurry on any of this, though.

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.

bavarian06

I not sure if it would work for you, but you may check your MAF to see if its faulty. My car would stall out if I stepped in the clutch suddenly, like coming to a stop light. At the time, I had to blip the throttle to make sure the engine wouldn't die out (talk about heel-toe) but the issue resolved itself after I cleaned the MAF.

Car runs perfectly now.

jakfrost

Yes, Steve Wong...and not sure how they know which DME, but the form you fill in during the order process is pretty simple. They only ask for the year and model, plus if you have had the LWF mod and the octane you regularly use, i.e. 91 or 93. Good question though, I'll check it tomorrow, or maybe late this evening when I get home. Since my car is a '95.5 version maybe there was a change somewhere there that could be part of my surging issue.

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

inkatouring

Jim: I have that same chip in my 95 w/ lwf and the stalling is almost all gone. Maybe once a month or two? But the idle is at 900 now, to stay there forever, I suspect.

Mike: PM sent re chip

bavarian06

MAF is the mass air flow sensor. Its this blk rectanglar shaped device with a circular attachment pt connecting it to the air filter box. Check to see its clean and properly connected. Maybe the previous owner forgot to attach it during the K&N filter change.

nile13

Jim, I did not mention cleaning MAF, but that is a very good idea. The other is - search for vacuum leaks right past MAF.

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

jakfrost

OK, had to remove the DME from its mount and pull it forward to get the picture, but here it is:



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

nile13

Jim, I'm more and more thinking towards the vacuum leak.

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!

nskd3

I'm interested in what you learn. I have a LWF, but stock chip and I get the idle surging ocassionally on cold starts. I haven't stalled in a long time, but I am careful about bringing the revs down to 1000 before I depress the clutch when stopping. Have been thinking about chipping the car, but have also been reading all the threads about the chips.