Embarrassed beyond....
I have meticulously rebuilt my engine over the last year after a catastrophic blow up about 4 years ago.. Block went to Hartech in the UK for bore out and installation of new cylinders and pistons, used LN Engineering (Rods, Pinning shaft, IMS,), Pelican (Parts and advice), LA Dismantler(parts) and Vertex (parts & engine Yoke)for my rebuild. Followed Jake Raby's step by step rebuild process (DVD) perfectly- Excellent teaching and always preaching care and caution. Jake was extremely helpful during the process. Well....got the engine and transmission back into the car.....lifted the battery that had been out of the Car for 3 years (new 3 years ago with big sticker on its front) faced the battery with the sticker side to the front of the car and hocked up the cables.....****....immediately pulled the cables off as weird sounds and horn noises....I had reversed the polarity. Can't believe I did not check something as so simple as negative and positive terminals, assuming that the battery marketing label attached on the front of the battery was meant to face front....NEVER ASSUME and always double check....I forgot everything Jake taught me.
I reconnected the battery correctly and found the following: Dash does light up with the key and steering wheel accessible programs all work (oil level, etc), alarm works, ...turned key, starter works perfectly, engine cranks well.....but absolutely will not start. I noted that my centre screen is not working, radio not working or any associated buttons, Navigation system with DVD dead (can't retrieve DVD in front trunk) and getting an engine warning light with exclamation point plus a Pasm error. Seems all other electronics are functional. Is it possible that all might be okay and that I incorrectly screwed the two wiring harness connections and maybe revered them?
I am thinking that most likely, I could have damaged my ECU DME and need to pull it and send it out for checking. Any other way of checking or any suggestions of what to check?
Thank you.
Beyond Embarrassed.

 

Did you start by checking fuses?

 

I'm sure this won't work but maybe disconnect the battery again for 10 minutes and reconnect? I know I use that for resetting some codes...

 

This is one the worst slip-ups a person can make when working on a car. Such an easy mistake that can quickly kill the car especially if not corrected immediately. Reversing the flow of current is a wicked killer. Remember, the flow of current is reversed and so you won't noticed blow fuses. I tried to help a guy in Canada that fried his 996 by reversing polarity. After noticing the many melted wire harness connectors and fried modules, the car was an obvious total loss.

I have to place a little blame on Porsche. Like most manufacturers that color the rubber shielding on the positive line red, Porsche leaves both + and - lines black. When you're tired, it's easy to forget which one is positive and which one is negative. I tell people to simple label the lines and even wrap the positive line with red electrical tape. Helps.

Sorry OP

 

Alright let's get to the specifics. If you didn't leave the reversed terminals connected for long, then it might not be as bad as it seems. Let's examine the obvious. The PCM radio needs a constant electrical flow to maintain presets, settings, etc. Therefore, more than likely you either did damage to the radio or caused the fuse on the back of the PCM to blow. Let's hope it's just the fuse. Check it out. If it's blown then replace.

Next, you also need to examine & test the alternator and possibly the starter.

Lastly, here's the BIG one... you need to check the ECU and immobilizer. If those units are fried, then the car will never start. You'll need to be prepared to replace.

 

Oh man. So sorry to hear this and know you must feel awful, especially after going through all the time, expense and delayed gratification of your rebuild.

A friend of mine made the same mistake earlier this year. Good advice above on the PCM fuse in the back as that one was blown for him (the only fuse blown BTW). His experience either toasted the alternator or hastened its death after 14 years. Most of the warning lights reset, but IIRC there was a Check Engine that required a computer reset. Beyond that, he noticed some battery drain issues after the incident which may or may not have been related.

Fingers crossed for a quick and painless resolution.

 

Have not yet but will be revisiting on the weekend....needed to step away

 

I have my fingers crossed that the momentary screw up did not kill the Car. Actually almost everything electrically works, with the exception of the screen, radio, starter but the crank turns but does not start. Think I might have damaged my ECU - DME and will look at sending out to get it tested, repaired or replaced.
Mark

 

Does the car have the cel light on when the key is on accessory

 

Thanks on the advice re the ECU and Immobilizer. Engine cranks perfectly with the starter but no ignition. Probably had the wrong terminal hooked up for 5 seconds. I was thinking that given almost everything else works it would be quite possible I have damaged the ECU. Not familiar with the Immobilizer...where is that found?

 

Thanks...Hopping...fingers crossed

 

Good question.....i believe so as all the door lights and trunk lights worked. Will be back at the car tomorrow

 

ECU doctors is the most respected independent company to assist with this type of failure. You'll need to remove the ECU, Immobilizer, steering lock module, and at least one key fob to them. (see picture)

The immobilizer is located on the firewall on the 997. There's a slight chance is under the driver side seat.

 

thank you….that is the company I was contacting. Thank you for the help.

 

Quick question....There are two round connectors for the wiring engine wiring harness , I assume that i can't mix them up and each receiver will only allow the matching end? (ie.-I cant mix them up)?
Thanks