DME replacement and a chip?

[cbeers]

Hey guys,

Long time no see
Work filter at the new job keeps me off of here but this is an emergency.

I have a track weekend coming up and had to pop for a new DME. Ouch.

Anyway, I have the new unit in hand and it clearly says if I open up the unit, the warranty goes bye bye. The trouble is, I have a Steve Wong chip in my car currently and would like to swap that over into the new DME.

If I decide to just run the new DME as is for the track weekend (just HPDE) will I be risking any damage to anything/running like crap or will the chip already inside the new DME re-map everything out and I'd be fine?

I am not concerned with the small drop in HP with going back to an OEM chip, just potential damage. I don't run a cat either.

I am inclined to just run the new DME as is for the upcoming weekend and deal with the chip later on, but want to make sure that's a sound plan first.......


Any insight on this is very much appreciated.

As well as any tips/pointers about the DME swap itself. I didn't find too much in the Bentley about DME replacement so any real world knowledge would be helpful.

-Chris

[MotoSook]

Chris,

If the DME box has a stock chip in it, and it matches the one you're replacing then it should be plug and play.

Changing out the chip is easy. Steve has a PDF on his 911chips.com site that shows you how to do it. You could just send your old DME box to Steve for R&R and you'll have a spare.

[DRACO A5OG]

Hey Chris,

No Worries. Just swap the DME's. You may need to reset the base idle due to the fact the OEM spec DME calls and adjusts for a Cat. It may idle too low. 880RPMS

The chip swap is very easy go to Steve's website www.911chips.com and it will give you a step by step procedure to swap. Just be very carefull prying the mother board apart. Do it on a table so you don't drop it. ( ask me how I know ) Use a small straight edge to pry a little at a time. Then the rear seperate slowly then lift. You will understand after reading the instructions on Steve's website.

[DRACO A5OG]

+1 on Steve's repair of the old DME. Very simple fix you can do yourself, just fyi

[cbeers]

Good info on this guys.

My original DME had the SW chip inside when I bought the car.

The new DME I just got has what I assume is an OEM chip.

Sounds like the only thing I might have to deal with is idle and for a track weekend, that's no biggie.

I wish I had more time, I would have just sent mine to Steve in the first place, but as is always the case with me, it became urgent in a hurry.

Maybe I can have Steve fix my original DME and then sell off this unit I just got and be out less money than I am right now......

-Chris

[DRACO A5OG]

Originally Posted by cbeers

Maybe I can have Steve fix my original DME and then sell off this unit I just got and be out less money than I am right now......

-Chris

Great Idea.

[cbeers]

One last question:

Should I disconnect the battery before working on the DME swap?

-Chris

[MotoSook]

I never do. Make sure to push the spring clip far enough off the DME connector, and the connector will come free fairly easily.

[cbeers]

Cool, thanks again!

-Chris

[DRACO A5OG]

+1 No need to disconnect the battery, Do remove the Key from ignition.

Before you set the Base Idle, if needed. Drive around for 10-15 mintues to allow the DME to reset the CPU.

[ischmitz]

What was the issue with the stock DME that you ended up buying a replacement if I may ask?

On the point of how to swap DME's you do not have to worry about the battery. Unlike later model cars the 3.2 Carrera DME doesn't have any permanent battery terminal. As soon as you switch the ignition to OFF there is not power to the DME at all and you can safely disconnect it and connect the new box.

As others said sometimes a new DME will cause idle to hunt. Steve Wong's website has a very nice tutorial on how to set base. Essentially, you have to place a jumper into the diagnostics port in the engine bay to center and disable the ICV. Then you need to adjust the air bypass screw to obtain a stable idle. This will move the ICV control range so it can regulate the airflow to maintain the programmed engine idle speed.

A DME can be damaged in seconds with a faulty harness or engine sensor and no seal would ever prevent that. So I don't see any value in these to begin with. If you are partial to the Steve Wong chip (as many are since it is a great upgrade) I would contact the place where you bought the replacement DME and state your case. That way they either can do the swap for you (hopefully at no charge) or you can do it yourself while keeping the warranty. There is really no point in sealing boxes to prevent false warranty claims. This seems awefully restrictive and doesn't really prevent any tampering....

A DME can be damaged in seconds with a faulty harness or engine sensor and no seal would ever prevent that. So I don't see any value in these stupid seals to begin with.

Cheers,
Ingo

[cbeers]

Follow up:

Swapped the new DME last night and all seems well. Even idle is dang close, good enough for now. Crossing my fingers for the weekend at the track.

Ingo, I did a bone head move. I was installing my roll bar, Targa top off, driver's seat removed when I stood up to exit the car with all of my tools etc. A tool fell on top of the DME box and gave it a good thump. Uh oh. Sure enough, from that point forward the car wasn't running right. Misses while driving, died at idle, backfiring etc. I knew I was screwed.

I looked inside the original DME last night since I'll have to pull out the SW chip before sending in for my core anyway and it doesn't look toooo bad in there

When I actually swap chips I'll figure out later. After the Sears Point weekend.


Thanks again to all for the pointers.

-Chris

[dshepp806]

Gotta' watch that "falling tool" thing! What tool (BTW)? Did it strike the cover (in general)? (NOT the connector..?) HEAVY tool? mmmmmm....did it leave a DENT?

Should there have existed a marginal solder joint within that DME, the "striking" could have compromised it. It will require some close (bright white light) magnified inspection, looking for any visually questionable joints (many good threads here on this experience).

Otherwise, it's DME test time...(signals, that is).

Best,

Doyle