Ninesircles

Hi All,

New owner so please bear with me.

Purchased a 1990 C2 Targa that had been sitting for a while from an old friend. Friend purchased a new battery she started up and was transported from Texas to California. Arrived with symptoms of a dead battery. Didn't think much of it, didn't even put the keys in the ignition, just rolled it in and started basic maintenance / tune up.

Well, here I am after doing all the maintenance trying to crank her up and put the keys in: nothing. Not even dash lights. Check the voltage on the battery, reads 12.6... hmm okay... check resistance from terminal to straps, looks good. Leave the battery on a trickle charger, take it to Autozone the next day just to have it checked and it passes. Try cranking again: nothing. Go through the car, clean all my grounds, add dielectric grease, etc and you know the rest. Put the battery back on trickle and started googling. Maybe Ignition Switch? Checked all my fuses, opened up my relays to look for some corrosion when I notice that my Starter Relay doesn't look right, it's this: Porsche Bridge Adapter Relay 964-610-184-00

This morning plug the battery back in and holy moly we have dash lights. Exclamation button above the spoiler controls is illuminated but I'm still searching for what that means. Try to crank, hear a click, and then nothing. Power cuts shortly after another attempt. After it died I left the battery connected and checked the starter's voltage and I'm hardly getting any juice back there. Can anyone point me in the right direction? I'm not the best when it comes to electrical but I have the time!

Relay 61 is bottom left. Should be identical to Relay 23 from my understanding.

r-mm

I'd suspect the battery cables. Remove, clean and (if in doubt, replace) the primary negative connection to the BODY. Clean both terminals. and both cable clamps at the battery. Move back from there, next stop starter motor connection. It is also quite easy to clean the majority of the ground, any of which can cause strange / irregular electrical behavior. There is a diagram of there locations in the electrical pages of the service manual with a handy elevation and plan wireframe. Unbolt each, brighten the contact on the body as well as the ring terminals themselves. Deoxit is ur pal.

newsboy

First,I would swap the DME relay. Now, do you have spark,gas? If not I would check the flywheel speed sensor.

r-mm

But…If you got no nothin incl dash lights interior lights key buzzer your problem precedes the dme relay…

Foxman

Agree with r-mmm. This sounds like a bad ground, or something is draining the battery is a god awful way.

0luke1

I had internal corrosion on a battery cable. The outside looked fine.

klokwerk

Hey Ninesercles, welcome....Merry Christmas!
So, what's the current status? Still getting nothing or something when you try to start it?
Also, "Exclamation button above the spoiler controls is illuminated" comes on for several things. For example: at start up it lights up if you've got your parking brake on and or while the ABS pump is priming but usually goes away shortly after all that.
It also comes on if there is a fault. It's not a problem if it's just at start up and then goes away. That's normal.

I'm curious if you've got a battery charger and just let it charge up over night and if you've tried starting it while the charger is still connected. What happens?
No blown fuses right?
So, are you getting power to the ECU under the seat? Did you disconnect it when doing your maintenance and didn't reconnect it? Is it loose?

As others have said, bad ground will do this for sure. But a bad battery too but you state it's a new battery...

Ninesircles

Thanks for the welcome and hope your xmas was merry! Appreciate the info on the exclamation button, I'm seeing it more now that the car turns on-- but to answer your questions in order:

The car does start now, there is a short in the fuse box's harness and it wasn't getting 12v. I ran a temp by pass from positive terminal of battery to the 12v terminals in the box and voila, she came back to life. Need to track down the short but so happy to hear her start for the first time.

No blown fuses that mattered (just one to the radio amp / antenna, changed out)

ECU was not getting power. Negative cable for the battery was switched out. Positive side was confirmed good by testing resistance from terminal to strap.

I stumbled upon the problem when I left my keys in the on position (by accident) and began fumbling with the fuse box, my son just happened to see the glove box light turn on momentarily. Glovebox was left open since it was the only light I had seen ever work (other than the exclamation point and dash).

Happy to report that I'm on to troubleshooting all new things!