97 993 wont start

[aigale]

it will start first thing in the morning but sporadic starting after that. Thought is was the immobilizer as arming and disarming resolved the problem. Now it happens more frequently and I have to arm and disarm several times before it will start. generally hear no sounds whatsoever when have the problem but once in a while will hear a hissing sound that when i arm and disarm again the sound will disappear. is this an immobilizer issue or something else?

[PNine64]

993s have the same DME issues as 964s don't they? Have you tried swapping that out? I know most of us 964 guys keep a spare handy for that "special occasion".

[Don Plumley]

How old is the DME relay?

[techman1]

Have someone hook a meter to the battery and monitor voltage as you crank to verify the battery has a good charge.

[PNine64]

If electrical, the battery ground strap can cause problems (and is cheap to fix).

[cgfen]

Originally Posted by aigale

it will start first thing in the morning but sporadic starting after that. Thought is was the immobilizer as arming and disarming resolved the problem. Now it happens more frequently and I have to arm and disarm several times before it will start. generally hear no sounds whatsoever when have the problem but once in a while will hear a hissing sound that when i arm and disarm again the sound will disappear. is this an immobilizer issue or something else?

Try the START relay, maybe #61???, in the under front bonnet fuse panel.
Just swap it with another similar relay, there are 4 or 5 identical relays used for various tasks.
I had a occasional no start issue, swapped the relay around and have been golden ever since.

Craig

[Groesbeck Hurricane]

I agree with the relays thought process plus it is rather a simple item to test!

Once the car starts running does the engine sound fine or does it skip, spew smoke, anything outside the ordinary?