'82SC Rev limiter

[930turbo]

Can anyone tell me where the electronic rev limiter is located on an '82 SC?

[1982911SCTarga]

It's the black box located under and behind the dash on the extreme driver's (left-hand) side.

Brian

[930turbo]

Near the light and ignition switches?

[1982911SCTarga]

Yes, but above and behind -- it's the largish square black box with a big "X" on the side.

Brian

[Innov8]

What is the RL set to on an 82sc? I have gone pretty high while running DE events and would be curious to know what the limit is. Is this bad to hit the limiter (other than the obvious reasons)? Thx.

[1982911SCTarga]

This is from Bill Verburg who posted on this in another thread:

oem limiter specs
930/03 & 13 6800+/-200
930/04 & 05 & 15 & 06 6700+300
930/07 & 08 & 16 & 17 6500+200

So, for your '82 -- if it's a U.S. version (930/16 engine) -- the rev limiter is set to 6,700 RPM.

Brian

[1982911SCTarga]

Is this bad to hit the limiter (other than the obvious reasons)?

I can't answer that question specifically, but I've never seen a reason to bang mine off the rev limiter or get even close to doing so. Bear in mind, however, that I'm not going 10/10ths at DEs either.

Brian

[930turbo]

OK, what you've provided has been very helpful so far and I want to thank you for your input. What I had was a dead ignition, what I have now is the car will fire once or twice when the key is in the start position if I disconnect the bl/vi wire from the tach. The fuel pump is running if I press the air plate so I'm certian I have fuel pressure/delivery. There is power the the ignition box and signal from the distributor. Do you have any advice?

[1982911SCTarga]

Let's back up a bit. What symptoms or maintenance issues got you to where you are? The reason I ask is that I wouldn't necessarily be digging into the rev limiter or tach as a first-look item.

Regarding this:

The fuel pump is running if I press the air plate so I'm certain I have fuel pressure/delivery.

What this confirms is that your pump is running, but it won't confirm if the pressure or delivery is in spec. This is why the CIS gauge is a must-have item.

Provide some more details and the way-more-knowledgeable people here will help you out.

Brian

[930turbo]

Previous service history is unknown, that's the challenge. What I know of the car is I was told the pistons were installed upside-down during a recent rebuild and the original mechanic quit. They were correct, I rebuilt it again and corrected the piston orientarion as well as changed the rest of the remaining head studs, no problem there. When I re-installed the engine in the car, it would not start. As it turns out, this was the problem that lead to the investigation of the piston problem. I doubt that was why it wouldn't start at all although still a serious issue. We've spent three days on troubleshooting electrcal problems and discovered a shorted trigger wire from the distributor, broken connection at the fuse block and traces of privious tampering throughout the wiring system in general. I bought into a rebuild and inherited an electrical nightmare, Now, I can't get paid for the part I know is right until I fix the unrelated part that's wrong. The needle is still somewhere in the haystack. 25 hours in the top-end job, 21 hours in subsequent the gremlin chase.

[1982911SCTarga]

OK, so we're in deep here. You might want to look at the alarm module and see if it's been disconnected and correctly jumpered. The failure mode of the module (it's a silver box about two-thirds of the way toward the right and under the dash -- hey, do you feel like you're living there yet?) is a no-start irregardless of whether the alarm has been activated or not.

Brian

[1982911SCTarga]

The correct disconnection and jumpering of the alarm module is as follows: Make up a short harness to connect the two pin 61s on the female connector. Tape off and cover the now unused male connector.

Brian

[1982911SCTarga]

On the '82, look under the passenger seat and see if the lambda relay is plugged in. If it's not -- or if the relay is duff -- the car will barely start and run terribly. Ask me how I know (OK, so I "borrowed" a known good relay to test in my other SC and forgot to put it back in my "good" car).

Brian

[930turbo]

OK, I pulled the air blower assembly out of the car and discovered the alarm module is missing. Does it normally connect with two plugs (white & black)? If so which wires need to be jumped?

[1982911SCTarga]

Check to make sure the car came equipped with a factory alarm. In '82, I would guess that most U.S. versions did (but having said that, I'm sure someone will prove me wrong). Look at the driver's door for the alarm key lock mechanism. If you can confirm that, then look for the unused connector under the dash, since you say the module has gone missing (I think the connector is a six- or eight-pin type, not a simple set of plugs). The pin numbers are identified on either the harness connector or the module (I can't remember which one, it's been awhile since I was sorting this on my car).

Brian

[930turbo]

It does have the key switch in the door. We took an alarm module from another car and the alarm is active (horn beeping etc.) We were able to identify the terminals and jumpered per your direction with the same result. More than likely, there are other issues related to the alarm wiring in the car. It's time to walk away from the project after four days - before we cheerfully burn it to the ground. Obviously you've lived the in the past and I appreciate your advice. I'm sure I'll be inquiring again in the future. Thanks again.

[1982911SCTarga]

Obviously you've lived the in the past and I appreciate your advice.

Too funny, I always have lived in the past with Porsches. I had a '63 coupe in the early '80s when the 911 SC was state of the art. That was in a time (no Internet, imagine that) when you had to attend your local PCA region's monthly meetings to pose technical questions, learn stuff and exchange ideas.

Today, I have two SCs while the bulk of the Porsche world has moved several generations beyond. I'm behind the curve and prefer it that way. Our cars are quirky, fun, and relatively easy to maintain and dead-on reliable once you're beyond sorting issues.

Brian

[930turbo]

I agree, that's why my personal example is a '77 turbo, which is number 8 for me. I've owned P-cars one at a time for several years. The cost keeps me 20 or so years behind the curve. That and I enjoy getting my hands dirty on occasion.

[930turbo]

Do you know what the alarm does to disable the car? The symtom is, it fires two or three power strokes then quits every time you hit the starter. Does the alarm remove the 12v from the ignition box? Does it ground out the trigger signal? If so, which wire, the black w/violet tracer?

[1982911SCTarga]

Warren Hall once posted this:

3. The factory alarm/theft-deterrent system has no schematic diagram in the factory service manual ... the one appearance being the Part I of the '82 USA 911 SC current flow diagram! In the last part of the electrical section of the manual there is a connector pinout and basic Voltage and test lamp checks ... AND an insignificant (to the writer, apparently) note saying that even without power, a failed Alarm Control Unit can DISABLE POWER TO THE FUEL PUMP, 'UNDER CERTAIN CIRCUMSTANCES!' MAYBE IT SHOULD BE CALLED THE OWNER DETERRENT SYSTEM? There is a workaround provided to disable the alarm system by jumpering both terminal #61 connectors at the alarm unit 8-pin socket ... after the unit has been disconnected!!!

The complete thread with a wiring diagram is here:'82 SC Won't run

There's also something about the dome light fuse sharing the same circuit as the lambda unit. You might want to check all of your fuses up front.

Also, what about running through the basics again? Fuel pump relay, wiring grounds, etc.?

Brian