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nynor 10-14-2003 09:02 AM

euro DME issues
i have two DME's for my vehicle. the original one mostly works fine. the main issue is with the second one, which is the early euro version, with advanced timing, etc.

the problems with the euro DME are as follows: very difficult to start the vehicle when the engine is cold, runs rough (and i mean ROUGH) until the engine warms, and most alarming of all is that it will simply stop running. the first time it stopped running, i was on the freeway cruising at about 75 MPH and the engine simply stopped running. i pulled over, could not get the car to start, after about 5 minutes, the car started back up at the first turn of the key. the next day, it did the same thing, only this time i had the original DME with me, which i swapped out on the side of the freeway and the car ran immediately. needless to say, i have been running the original DME ever since and the car has not had those problems.

i would really like to be using the euro DME, as the car has noticeably better power and revs much faster. any ideas as to the nature of the problem will be appreciated.

nynor 10-14-2003 11:23 AM

i just read somewhere that there may be solder issues. i am going to try re-soldering all the connections when i get home today. failing that...

nynor 10-14-2003 05:39 PM

well i guess i am talking to myself ;)

today i opened the dme in order to re-solder connections. there was a definite burnt smell inside there, like one or more of the electrical components let out its magic smoke. so i re-soldered anyway.

when i plugged it into my car, it would try to fire up and then die, but mostly, it wouldn't even try to fire up. i believe it wasn't getting spark, because there only the smell of raw gasoline coming out of the tailpipe, which leads me to believe that it IS getting fuel, but NOT getting spark.

so there you have it, folks, the latest information.

once again, if anyone has further ideas, please share them.

or, if you are in the market for a euro DME as a core, let me know.



Porsche944 10-15-2003 06:00 AM

You should not be running a Euro spec DME in a US spec car. The Euro spec cars have a higher compression ratio, do not have a CAT, do not have an O2 sensor, and run at a lower fuel/air ration (richer).

Running the Euro spec DME will waste fuel, trash you O2 sensor, and ultimately clog the CAT.

If you want to run a different DME, try installing a late model (85.5 to '87) DME and AFM. You need to change both parts because the late model DME uses a 5 volt reference, and the early DME uses 8 volts. This is a "plug and play" swap. No need to chagne the DME harness.

daveimme 10-15-2003 06:33 AM


Originally posted by Porsche944

If you want to run a different DME, try installing a late model (85.5 to '87) DME and AFM. You need to change both parts because the late model DME uses a 5 volt reference, and the early DME uses 8 volts. This is a "plug and play" swap. No need to chagne the DME harness.

What changes are noticed if the afm and dme are both swapped out? There are two 944's at a local wrecking yard and the good thing is the owner doesn't like porsches at all, but carries all other german cars in his yard, and it would be easy and cheap to get these parts if they are still on the car. Which is why I would like to know what changes/characteristics to expect with this swap. And pros/cons of doing so.....

Porsche944 10-15-2003 08:07 AM

I had a problem with my '84 that swapping the AFM and DME fixed.

The issue was if the electrical system was loaded (head lights, cooling fans, and /or A/C on), the engine would "stumble" at about 4500 RPM under hard acceleration. If I "feathered" the accelerator the engine would accelerate normally, but I never could hit the rev limiter. The engine also had the infamous "944 Shudder" as described on F.R. Wilk's site.

On a hunch I swapped the DME and AFM, and the results were quite dramatic. The shudder and stumble are gone, the engine runs smooth as glass, and I can hit the rev limit at will.

I have since added F.R.'s "Shudder Fix" adapter and chip the the original DME, but the engine still stumbles. I suspect component ageing of the injector drivers is the cause, but I have not been able to locate replacement drivers.

An additional upside to swapping the DME and AFM is you can add a "performance" chip.

daveimme 10-15-2003 09:47 AM

Oooohhh, that sounds good. I gotta go see if they still have these two components.

I have checked into getting rid of the shudder on my 83 944, but the cost is too expensive for me, having to obtain the adapter and chip. The shudder is not so bad unless I am running the ac, then it is noticeably worse.

If the junk yard has the afm and dme to sell, what is a good price to 'haggle' for?

Porsche944 10-15-2003 11:47 AM

I don't know what you would consider a "good" price, but some time ago I paid $250.00 for a late AFM, and a late DME with an AutoThority "performance" chip.

I have seen several late DMEs and AFMs recently on eBay, but you have to pay close attention to what you are bidding on. When in doubt ask the seller for the part numbers.

You do not want parts from an '88 or later.

daveimme 10-15-2003 11:57 AM

So, do you have a part nbr for what I am looking for? I would guess from an 85.5 to an 87 is what I could use, correct? I know the local yard has 2-85.5 up, though I do not know the exact year, but with a part nbr, I can be sure to look for the right thing. At lunch today, my mechanic said that another yard just got a 'later' 944 so I could check with that one, too.

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