71' still not running. can it be this?

fierochris · 11-12-2006, 11:59 AM

Ive been on this project for about four weeks now. the car is getting plenty of fuel. its turning over fine. just no fire. here are a couple pictures of things that have been making me wonder.

(1). is it missing something here?

(2). what is this switch for? the car has PMO carbs installed. is it no longer needed?

(3). this connector is just laying on the top of the engine, along with a single wire. becuase of the pmos maybe? needed?

(4) i found this, it looks to be a lung in for a relay? its near the battery tray. any idea what its for?

(5) and finally. this wiring. does it normally just lay free like this?

Thanks, Chris.

LakeCleElum · 11-12-2006, 12:28 PM

Pic. #4 looks like the plug that goes into the inside of the fender to get power to the headlight on that side.

#5 - Fuse block should be mounted on the fender well.

fierochris · 11-12-2006, 12:44 PM

Quote:

Originally posted by LakeCleElum
Pic. #4 looks like the plug that goes into the inside of the fender to get power to the headlight on that side.

#5 - Fuse block should be mounted on the fender well.

i just went out a look at how it cuold be mounted. but im thinking thr fuse block is from a different car. its a mecedes benz fuze block. the fuse blocks were not MB were they?

Jim727 · 11-12-2006, 01:33 PM

(2) is the activation switch for the idle overrun enrichment.
(3) iirc is the connector to activate the idle overrun enrichment solenoid.

Don't see why you would need either with PMOs.

(5) Yikes - needs some help. Should be attached and protected.

Tyson Schmidt · 11-12-2006, 01:51 PM

None of those things will cause your no-start.

If you have no spark, check that the points are clean, and opening. Check power to the CD box with the key on. (it should "whistle" with the key on) Check that you have a signal from the points to the CD box by unplugging the connector form the cd box, attaching the ground clamp of a test light to power, and stick the probe into the terminal for the black wire, and crank over the engine. The test light should flash on and off.

The 14pin connector at the front of the engine fuse board is a likely suspect if you aren't getting power to the cd box. The red wire that branches off from the harness attached to the CD box should be connected to a connector that goes into the fuse board wiring harness, That's how the cd gets power. You could run a jumper to it to test.

304065 · 11-12-2006, 02:21 PM

Wow. Chris, I'm going to give it to you straight like any good doctor would. That electrical system is a major-league hackjob by at least one prior owner that's going to make diagnosis very difficult.

First of all, in a 1971 911, in those holes on the electrical console there's a cylindrical can called an "intermediate unit" whose job it is to create high-voltage pulses for the 1971 tach. Not until 1972 did Porsche/VDO change the tachometer to a "high impedance" design that could trigger directly off the very small current in the circuit from points to Bosch CDI.

For more about this, see here: Tach - oh - woe (pre '74)

Now, since that's usually connected to the CDI and the points, and if the wires for it are just layin' against the sheetmetal of the electrical console, that engine won't start, even if you say a prayer to Nikola Tesla while holding a #2 iron in a thunderstorm!

You know who the smartest guy when it comes to electrical stuff is? Warren Hall, a/k/a/ Early_S_Man, who has done it ALL when it comes to MFI. But until the Guru appears, you're stuck with me, posting his diagram! So here it is. And I think he's actually revised it lately, with better colors on the wiring, so you can really see what it's supposed to look like!

So start by following the diagram, make everything look like it does there. Ignore the wires to the speed switch labeled as #5 in the diagram. And be careful, the CDI output is a 460 volt shock, I don't know if it can kill you but I don't want you to find out.

Switch #2 is the overrun switch, it is not used with PMOs. Ignore it.

Connector #3 is the factory connector for the old fuel pump mounted down under the car by the rear wheel. Since you are using PMOs, there's probably a different fuel pump somewhere. Tape it off and ignore it.

Fuse block #5 makes my cry. Somebody has cut off the original fuse panels and crimped Radio shack terminals on the ends and stuck them in a non-OEM fuse block. Sorting that out is a 100 hour project. I would start by getting the two original fuse blocks out of a wreck, with as much of the original wire harness as you can, remove everything, and see what wires you can identify in that harness that are original. They're in there, all right, those white wires with green stripe are factory. . . the grey looks original. . . might be some light at the end of the tunnel here.

As a guide, download the original wire diagrams and print in color.

http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm

Good luck!

Zeke · 11-12-2006, 02:57 PM

No. 4 could be for a relay. There is one normally at the bottom of the fuse block which normally attaches vertically to those L shaped tabs you see on the inner fender. Don't know for sure, but if your headlight/turnsignal harness IS in place on the driver's side, then it might be the horn relay.

What does the rest of the car look like? Kudos to you for working to save it.

fierochris · 11-12-2006, 03:04 PM

Quote:

Originally posted by john_cramer
Wow. Chris, I'm going to give it to you straight like any good doctor would. That electrical system is a major-league hackjob by at least one prior owner that's going to make diagnosis very difficult.

First of all, in a 1971 911, in those holes on the electrical console there's a cylindrical can called an "intermediate unit" whose job it is to create high-voltage pulses for the 1971 tach. Not until 1972 did Porsche/VDO change the tachometer to a "high impedance" design that could trigger directly off the very small current in the circuit from points to Bosch CDI.

For more about this, see here: Tach - oh - woe (pre '74)

Now, since that's usually connected to the CDI and the points, and if the wires for it are just layin' against the sheetmetal of the electrical console, that engine won't start, even if you say a prayer to Nikola Tesla while holding a #2 iron in a thunderstorm!

You know who the smartest guy when it comes to electrical stuff is? Warren Hall, a/k/a/ Early_S_Man, who has done it ALL when it comes to MFI. But until the Guru appears, you're stuck with me, posting his diagram! So here it is. And I think he's actually revised it lately, with better colors on the wiring, so you can really see what it's supposed to look like!

So start by following the diagram, make everything look like it does there. Ignore the wires to the speed switch labeled as #5 in the diagram. And be careful, the CDI output is a 460 volt shock, I don't know if it can kill you but I don't want you to find out.

Switch #2 is the overrun switch, it is not used with PMOs. Ignore it.

Connector #3 is the factory connector for the old fuel pump mounted down under the car by the rear wheel. Since you are using PMOs, there's probably a different fuel pump somewhere. Tape it off and ignore it.

Fuse block #5 makes my cry. Somebody has cut off the original fuse panels and crimped Radio shack terminals on the ends and stuck them in a non-OEM fuse block. Sorting that out is a 100 hour project. I would start by getting the two original fuse blocks out of a wreck, with as much of the original wire harness as you can, remove everything, and see what wires you can identify in that harness that are original. They're in there, all right, those white wires with green stripe are factory. . . the grey looks original. . . might be some light at the end of the tunnel here.

As a guide, download the original wire diagrams and print in color.

http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm

Good luck!

Thanks for the impresive responce. im going to start researching right now. but a quick question or two first.

your saying that with out the cylinder looking relay type parts that go in the holes on the metal structure in picture #1 the car will not start? if these are the parts, what exactly are they called? i would like to purchase them from pelican right away.

also if my harness is hacked should i replace the harness. or just the fuse block with the proper one and re wire it from there to factory specs?

fierochris · 11-12-2006, 03:11 PM

Quote:

Originally posted by milt
No. 4 could be for a relay. There is one normally at the bottom of the fuse block which normally attaches vertically to those L shaped tabs you see on the inner fender. Don't know for sure, but if your headlight/turnsignal harness IS in place on the driver's side, then it might be the horn relay.

What does the rest of the car look like? Kudos to you for working to save it.

the victim of the porsche abuse.

Zeke · 11-12-2006, 03:38 PM

That's the greatest picture I've seen in 5 years here. I mean the wash tub makes it complete! This, folks, is what Norman Rockwell strived to portray. I tell ya, if you had a roll of paper towels and a Marilyn Monroe poster on the door, that whole scene would be right for the Smithsonian or Peterson.

Love the gasburners. Are you one of the ones selling those? Don't.

MaquinaVerde · 11-12-2006, 05:14 PM

This diagram helps illustrate what should and should not be on the panel in the engine compartment:

You can see that you're missing the "RPM Sensor" for the pre-72 tach as mentioned above.

For comparison, here is the panel from my previously unmolested '70T after I cleaned it up a little. Sorry about the crummy photography.

I have detailed pictures of the various connections and underside from before I took it apart if you need them.

Gogar · 11-12-2006, 07:34 PM

+1 on the gasburners.

Is this the car you traded your kit car for a while back?

john70t · 08:25 PM

Try to simplify everything, and find out what is needed to start the vehicle. Fuel+Air+Spark.

In #1, it looks like the two missing relays are for the back window defrost and something else not labeled in the diagram. I think these can be ignored.

In #2, it looks like a speed sensor switch used by the MFI. It may just as well be ignored since your using mechanical carburators. I don't know what ithat switch affects.

In #3, That looks like the disconnected coil wire going to the center of the distributor cap.
If it is, the high voltage spark generated by the CDI and coil won't go through the rotor/cap/wires/plugs.

In #4, my guess is that is the connector for each of the front headlights. Same as the upper-right most connector in picture #5

In #5, duct tape and a missing battery is a bad sign. There are several extra attachments to the positive battery connection that may go to an aftermarket stereo or something else unecessary at this point. Was an alarm previously installed?

Also, if the engine hasen't been started in a while, make sure the oil is fresh and the battery charged beforehand.

fierochris · 11-13-2006, 12:30 AM

Thanks for the replys guy's! really! this shows how great this forum really is. im honored to share it with such wonderful people!

gogar: yes this is the car i traded my V8 Diablo replica for.

it may not be as fast, it may not get as much attention, it may cost more to maintain (or even get going) But the lamborghini replica will never have the taste, the pure feel. or the nostagic aspect that a original legend can give you, its a one of a kind feeling. and no matter what my kitcar could do or attract its still just a fiero with a powerful drivetrain and a exotic poser body.
I traded for the 911 because my interests changed. When i started that project i wanted something with exotic (flashy) looks and i wanted performance to match. And other the last four years of building that car my automotive tastebuds grew a bit. and the car that was everything to me suddenly wasnt. no one respects a kitcar. and after building the car with my own bare hands i was surprized that i didnt care that much either. and i couldnt help but wanting the real thing. a real car. and one that was born perfect. and didnt need to be altered to make it a dream car. it was already perfect. already refined. I feel like the luckiest twenty year old alive.

project 911 · project 911's Garage

Chris- Wow, I'm having flashbacks...

Let's see if I can help at all here.

#2 can be removed as it is no longer needed. (worked with Zenith carbs). You may also have a stray wire (gray and red I think) running over toward the right carb, that used to connect to a solenoid on the Zeniths. You don't need that.

#3 should connect to a sender (thermal time switch) mounted on the breather cover (next to the large oil breather hose behind you hand in the picture). There are two sizes of connectors inside that boot on the end, so you can tell which wire goes to which connection.

The rest is pretty grim, but I assume it must have worked at some point, so maybe you can work it out. I'm posting a few diagrams that I made while working out my system. Not sure if they are completely accurate, but maybe something will come in handy.

Ignition layout:

Fuse box wiring:

My fuse box detail- Little yellow lines indicate connections that are bridged on original fuse box. Table on the right indicated what amp the fuses were.

304065 · 11-13-2006, 05:50 AM

Chris, the "Intermediate Unit" is NLA (No Longer Available) you cannot buy one new from Pelican, or anywhere for that matter. Your only option is a wreck, but you don't need that to start the car, you only need it to drive the tachometer, so it's not an immediate fix, it's more like something for your second week of work on this problem.

But as the diagram indicates, there is a red wire with white stripe that goes from the CDI's high voltage output terminal (Terminal "A") to the intermediate unit. If the wire is just laying in the console, that's a problem, because it will short out the CDI. So find it and tape up the end so it doesn't short and that's one problem out of the way.

Uhh, a "new" harness is probably well north of $1800 so you're better off fixing the one you have, unless you intend to do a complete restoration down to the bare shell and back.

Oh, and about #4, the way Porsche attached the smaller wiring harnesses for the turn signals, etc., was through connectors like that. The white plastic part is the "male" piece that fits into a corresponding black rubber "female" piece that fits through a hole in the body. You need to take all that tape off there and trace everything out and find out which harness it goes to. Then find the hole for the female piece, lube the rubber up with motor oil and stick it back through the body.

The relays mount to rubber connectors also, one of them is shown in your picture, but the relay sockets have a rubber protrusion on them that mounts through the holes in the sheetmetal brackets welded to the vertical wall of the trunk just aft of the battery box. Again, once you get everything figured out, just lube the ends up and they should pop back in. New relay sockets ARE available from Pelican albeit with the wrong wire color.

A note about rewiring: the reason we have for years told people "when you replace wires, don't deviate from the factory colors" is for problems just like this-- we can tell you without seeing it the way every circuit in the car works, but it's impossible to guide you by remote control if the wire colors don't match. I'm not telling you this to make you feel bad, I'm recommending that you use the correct wire when you put everything right again. Diagnosis will be easier and the Porsche G_ds will smile on you.

For the correct wire try:

www.ynzyesterdaysparts.com
www.riwire.com
www.eagleday.com

And Good luck! It's gonna take a lot of beer and patience but you WILL get there if you follow the diagrams.