C4S993

Same thing happened to me yesterday. I read your issue and then went out and started car and later in morning same problem, it would NOT re-start ! After all eve and this morning, the problem turned out to be a newly acquired DME relay from AutohausAZ had a sale on 993 DME relays so I bought one and installed it last week. It lasted one freaking week. I just placed a donor factory-made Porsche 993 DME relay in and it fired right up ! The one week old non-factory made DME is dead as a door-nail. By the way, the AutohazAZ DME supplied DME relay was $cheap and made by "UROparts"; so it was not a factory-made DME.

John W

Been out all today on my bike. Lost one day dicking about with the car this weekend and didn't want to lose another one when the weather was good

I did try the car again when I got home on the bike, and still the same. I will take another look tomorrow night.

I'm not sure why you guys would suggest the battery when it spins the car over fine. Surely if it were the battery, that would be an issue too ?
Sorry, but just querying because you guys must be thinking of something I've not considered.

I don't have a different battery except on my other cars. I will try to connect up some jump leads.
It has been on the trickle charger so fairly confident its not low.
I will check what the voltage drops to when cranking too just incase.

Are there any hidden fuses, except those in the front and the box in the left rear ?
I have checked all of them and none blown.
I'm wondering if there is another somewhere I dont know about

Re the alarm, It didn't think it mattered if the led does a double flash, once you unlock the car with the key it is mobilised as per normal, or at least always has until now.

I'm kicking myself that I dont have an obd scan tool, as I'm sure that would show me something.
Tempted to buy one tomorrow. I've seen the Piwis lead / software, and durametric. My mate has an autel md702 but not the right lead for the 993.
Is the 993 obd1 or obd2 ?

Cheers,
John.

BesideTheBox

John - I would think that your early ('94) 993 would be OBD1.

These cars are getting up in years now and any time you spend cleaning grounding points will be time well spent. I previously posted some information with the grounding point locations in the 993.

John W

Thanks, will do that tomorrow (well tonight now).
Also going to run through the dme diagnostics as best I can without the service tool (been reading through the diagnostics section of service manual tonight).

so if it is obd1, I assume my choices are limited with respoect to diagnostics software / readers ?

John W

Thinking this through again this morning, I had the carpets out to vacuum them before I attempted to leave, so wondering if I have dislodged something in the process, like one of those earths :-/
I really hope it turns out to be something as annoyingly simple as that.

jstyer

You are correct. With OBD1 your options are pretty limited as far as readers go. Many have had luck with the Durametric scan tool as far as reading codes and viewing parameters on the OBD1 system. But I could never get the durametric scan tool to clear codes for me. I have had good luck with a BAUM DS series euro scan tool owned by a buddy of mine. They are very high dollar, but I have been able to access and clear all of my codes and parameters.

For 100% compatibility, on the OBD1 cars the Bosch Hammer is still the go-to scan tool.

C4S993

Why can't you just install a new DME Relay ?

John_993

Once had a similar problem... Turned out to be loose connector to the immobiliser box.
I spoke to the firm who supplied and fitted the pa alarms as the cars came into the country.. boxes are either under the drivers side dashboard or sometimes under the drivers seat. Mine was "floating" under the dash - pushed the connector blade back on firmly and secured the box to the dash

John W

WEHEY !! She Lives !!!

Sure enough, it was the earth on the left hand side at the Rear of the seat (had already checked the front ones).
It wasn't very loose, but loose enough to spin on the stud if pushed. I took it off, gave it a quick wipe with a bit of wet & dry paper, put it back and all is well once more in my garage
I did go around all of the others up front too, and they were all fine.

Thanks very much for all your suggestions, and of course your patience with my ramblings.

I have decided I am becoming stupid. Either that or senile.
In my office I have the full set of 993 workshop manuals, and it wasn't until yesterday evening the thought occured to me that I had these, and ought to follow them
In my defence, I've had the car since 2000 and this is the first time its given me any issues
Secondly, I knew that you guys on here would help me out

By the way, is Robin of p-car.com still on here ?

Aussie Alan 993

Well done for working it out, i'm glad to hear it is sorted and thanks for posting the solution to the problem.

Cheers
Alan

JB 911

Glad you got it sorted.

Sometimes I feel the same way. The good news is if it is the latter we will soon forget about both

I haven't seen Robin post on here in the last year or so. I might be wrong, but I believe he moved on to another model or marque. The current owner of Robin's 993 is on here though. I can't remember who it is but he has "Previously Robin Sun's car" In his signature I thought that was pretty neat.