Resetting 3.2 DME

[targa911man]

In the past I have mentioned in response to "starting problem" threads that I recalled reading on a thread somewhere that you can sometimes solve the problem on 3.2's by "resetting" the DME computer by turning the ignition to "on" (not "start") and slightly depressing the gas pedal for at least 11 seconds. I had never had any personal experience with this.
Yesterday I got home after a 10-day vacation with a serious jones for my Targa. Unfortunately, although I rushed to the garage to go for a drive, my car did not rush to start. The engine would turn over but not ignite, like it wasn't getting spark or fuel. This had never happened before. I should also mention that I did not hear the fuel pump starting. After 2 or 3 minutes of intermittent cranking with no success, I tried the reset method: I turned the car off, turned it to "on", depressed the gas pedal slightly (1/4 to 1/3) and held it, counted to 15 slowly, and turned the car off. When I turned it back to "start" and it rumbled to life like normal.
I do not know what causes the need to reset the DME, why this works, or even if what it does is in fact to reset the DME, but if you have a similar starting problem, seeing as it only takes 11 seconds it might be worth trying before you disassemble your engine.
I'd also like to hear if anyone else has had success with this method in similar circumstances.

[stlrj]

DME relay failing?

Joe

[targa911man]

I didn't change the relay. If it was a relay failure, could it be cured by the described method? I thought once the relay fails it's damaged and has to be changed.

[rbertels]

I had a similar problem one day last April where the car would crank but not start and a few minutes later it started like I never had a problem.

That same day I also had a couple of situations on my way home from an Auto-X where the car "cut out" twice for a fraction of a second.

I followed the advice of the board and replaced the DME relay and also upgraded to the new cylinder head temp sensor.

There has been no sign of the problem since then. By the way when I took the DME relay out and shook it, it seemed as though the internals were loose in the housing. I'm not sure if that was part of the problem, but I no longer have any starting/cutting out problems.

rbertels
87 Coupe

[jlex]

I may have missed that bit of advice if it was ever posted in this forum. If that really is a legitimate procedure, it seems we would all have been posting about it.
Can't remember what type of car I was reading about (definitely wasn't Porsche), but the car's computer could be reset by totally disconnecting the battery, then holding the terminals together for a few seconds before reconnecting the battery. Anyone ever heard of that one, or is it just another urban (garage) legend?
regards,
jlex.

[targa911man]

I have a spare relay that I carry in the trunk which also has some inside movement when you shake it. I tested it when I first got it to make sure it worked ok and it did.

[Tim Polzin]

There is a little bit of RAM memory within the CPU of the DME. Disconnecting the main connector to the DME for perhaps a minute or two (five minutes would be safer) would ensure that memory is cleared.

The hardware in the DME reboots the CPU each time the unit is turned on.

Tim

[weber92037]

Where is the DME relay located on a 1987? Thanks.

[john walker's workshop]

black plastic 1x1x2 box right next to the computer.

[Rick Lee]

This stuff really has me wondering what my problem is. A new relay didn't do it. I straight-lined the fuel pump and it barely moved. So I hope replacing it does the trick. The DME "resetting" did not work for me.

[targa911man]

I don't think I read it on this forum. I was searching the web for solutions to hot start problems and came across it. I'm going to search again and will post the address if I can find it.