74 914/2.0 Electrical problems

[tmeracz]

Hello Porsche people. This is my first post here but likely will not be my last.

I have a 914 that has been garaged for the past few months while the brake system received the 320i caliper upgrade, 19mm 911 master cyl and new rotors. Shifter and pedal box bushings were changed and a brand new Optima battery was relocated to the rear boot with a fuse block added in the engine compartment.

So now that everything is situated, I go to start the car and I get no love.

The starter cranked over a few times but the car did not ignite. I could hear the fuel pumps working, smelled gas, and heard relays in the engine compartment click, but got no ignition.

In addition, I smelled a burning short when I turned on the lights. The left front turn signal and side marker stayed lit after I pushed the switch back in and the circuit kept frying until I jiggled the key in the ignition switch.

I've gone over my connections with the fuse block, checked grounds and added a relay near the starter to bypass bad wiring that may be the cause of the no-start. Still no help.

(I also noticed that the cable to the starter kept popping its fuse- can anyone tell me what Amp rating this circuit needs? Currently I have 20Amp fuses in the other connections in the block but have bypassed the fuse on the starter for now with a solid slug.)

With the starter fuse in the engine compartment bypassed, I then cranked the car again and checked for spark across the plugs and saw nothing.

My first suspect with the short in the dash was the aftermarket alarm from the previous owner, which I removed. I had the gauges and fuse block out to do this, and despite my best efforts to take care some of the plugs from the gauge cluster and fuse block came loose.

I had a rat's nest of wiring to deal with but I finally snipped out the leads for the alarm and I am back to what I HOPE is a stock Porsche wiring situation.

I replaced the dislodged plugs although I am not sure if the loose connections were all put back properly. As of this point, the car still cranks but I get no spark and no ignition. And the short in the lighting is still there and still smoking like the Godfather.

So my first question is: where can I get a GOOD shop manual for this car?

I need something as exhaustive and thorough as the Helms manual with torque specs et al like what I have for my Honda. With a wiring schematic for the car and for the fuse block that I can actually decipher and understand.

I have the Haynes manual in my hands for 2 weeks now, but I'm sorry, people, this is a bad joke of an excuse for a proper shop manual. The print is vague and the diagrams are often not complete.
C'mon... how can you put up with this?

Secondly: what do YOU (I'm speaking to the DIY'er heads on this forum) really do with the stock Porsche wiring when you go through a rebuild or a conversion? 30 year old wiring with its corroded contacts just doesn't seem to cut it for me.

My gut feeling is to rip it all out and purchase an aftermarket harness and fuse block from Painless Wiring just so I know what's really going on with the car electrically. But going back to square one will be hard if I don't have a grasp on the car's electrical system to begin with.

Can someone here with that knowledge point me in the right direction? There are some great tech articles here on everything else, but precious little on really getting into the wiring of the 914. What do I need to know about with regards to the cluster? What systems and relays are inter-dependent? How can I make sure the seat belt circuit is really defeated and not coming into play? What other quirks should I look for? And why isn't my 914 starting?

[jamcleod]

914 guru Dave Darling would recommend getting the Haynes manual. a good $20 investment that has many of the Porsche workshop manual pictures and diagrams. that said, the factory workshop manual is available FREE online but i've said enough about that as that info gets our host in hot water with the P-factory. so, get the haynes and surf.

[karaoke_carlos]

This is an awesome resource. I've used his diagrams (914GT) before. They are nothing short of a GODSEND.

KUDOS

Also, DO get the Haynes manual. Ask a lot of questions. And if you want more help, also try www.914club.com.

[skline]

Originally posted by karaoke_carlos
This is an awesome resource. I've used his diagrams (914GT) before. They are nothing short of a GODSEND.

KUDOS

Also, DO get the Haynes manual. Ask a lot of questions. And if you want more help, also try www.914club.com.

But not today or tomorrow. Its down right now for the next 24 hours of withdrawl for those of us who are addicted to that site.

[Dave at Pelican Parts]

Originally posted by tmeracz
The starter cranked over a few times but the car did not ignite. I could hear the fuel pumps working, smelled gas, and heard relays in the engine compartment click, but got no ignition.

Check for +12V at the coil (+) terminal when the ignition key is in the "on" position. If you have a Pertronix, have someone turn the key to "on" after you have the voltmeter set up--and don't leave the key on for more than 30 seconds or you risk frying the sucker.

If that works, then make sure the points are opening and closing and you are getting a ground and then no connection at the coil (-) terminal.

In addition, I smelled a burning short when I turned on the lights. The left front turn signal and side marker stayed lit after I pushed the switch back in and the circuit kept frying until I jiggled the key in the ignition switch.

No clue.

(I also noticed that the cable to the starter kept popping its fuse- can anyone tell me what Amp rating this circuit needs? Currently I have 20Amp fuses in the other connections in the block but have bypassed the fuse on the starter for now with a solid slug.)

Starter fuse? I don't believe there is such an animal! The fuses on the relay board are for the fuel pump and the heater blower circuit, or unused. (Think of it as an "on-board spare". )

So my first question is: where can I get a GOOD shop manual for this car?

I need something as exhaustive and thorough as the Helms manual with torque specs et al like what I have for my Honda. With a wiring schematic for the car and for the fuse block that I can actually decipher and understand.

There is no such animal. The Helms manual, BTW, totally rocks--it's the best single automotive manual I have seen so far. The factory 914 manual is copied, word-for-word and photo-for-photo, in the Haynes book. Only Haynes leaves out all the excess "white space" and about 5-15% of the sections. In other words, the Haynes is as good as it gets...

BTW, color versions of some of the factory diagrams (replicated in B&W in Haynes) are available elsewhere on this very website.

Secondly: what do YOU (I'm speaking to the DIY'er heads on this forum) really do with the stock Porsche wiring when you go through a rebuild or a conversion? 30 year old wiring with its corroded contacts just doesn't seem to cut it for me.

My gut feeling is to rip it all out and purchase an aftermarket harness and fuse block from Painless Wiring...

I doubt that Painless makes anything for the 914. What most of us do is clean up and repair what we have. Some folks opt for NOS or sometimes used wiring harnesses from swap meets (if you buy from the dealer or from a parts house, you'll pay a whole lot as those buggers are quite expensive!) which is also a pain to deal with. The removal and replacement process is not that much fun. (Ask Sir Andy; he's done the job more than once!)


I hope that this helps you out at least a bit...

--DD

[tmeracz]

Well that color schematic already helped me pick out a few problems with the cluster wiring- 12V was run into ground, hence the frying in the lightswitch.

The car still won't start. I'll have a friend over in a few hours to turn the key while I test the starter leads et all.

When this car gets some more down time, I'm still leaning towards ripping all this old wiring out and starting all over... Painlessly.

Bummer about the Haynes manual. They really ought to stick to making underwear, IMHO. But the info I get from you guys is rock solid. I'll be asking lots of questions, thanks for the help!