My '72 quit on me today...help

[jond911]

I'm hoping someone here can give me some insight on where to start with this problem.

Got my '72T out today, first time in about a month, drove around the block a few times and parked it. Washed the car, dried thouroughly, waited about an hour and drove about .5 mile to nearest gas station to get some air in the tires. On the return trip home, I'm driving slowly through a church parking lot in first gear, notice the charge light come on and the car just dies. Fuel pump still running, engine turns overs but appears to not be getting any fire?? I've never noticed this before, however, now when attempting to start the charge light, "bottom" light, stays on.

This bastardized example of a 911 is a 72T with a 71T engine and 901 tranny. Weber carbs and permatune unit.

Could someone please tell me where to start here..... voltage checking, etc...

Any feedback would be greatly appreciated!

Thanks

[pwd72s]

I'd say go with the easy things first...pull the distrubutor cap, make sure all is dry inside the distributor...

[304065]

Well, the charge light coming on is GOOD, that tells you you have good battery current flowing back to the alternator.

What is the battery voltage, measured up front at the battery terminals? Are you still using two batteries or have you switched to one?

If the engine cranks over quickly and you have good voltage (around 12v) then I'd start checking the ignition system as PWD said above.

[jond911]

Battery voltage is good.... Switched to one battery setup, "Optima" about 5 months ago.

Will check distributor....

Any other suggestions??

thanks!

bump

[Bobboloo]

I'm not familiar with Permatune but the factory units have a high pitched whine when they are getting current (i.e. ignition on.) You might check this.

[autobonrun]

rather than the charge light coming on first then the car dying, perhaps it died, then the charge light came on. This would shift my thinking from an electrical problem to a fuel problem. Parking lots bring to mind speed bumps which bring to mind a jolt to the electrical fuse box. Could the fuel pump relay or fuel pump fuse have come loose?

[911pcars]

Combustion needs three things: air, fuel and spark.

I'll assume you have air where you are and the engine is able to breath as much as it can (throttle valves can open? Okay).

Next, check for spark. Remove the coil wire from the distributor cap, position it close to ground, then crank the engine. You should see and hear a healthy spark jump to ground. To verify the spark is getting past the distributor cap and rotor, repeat this at one of the spark plug wires. No spark? As suggested, does the Permatune hum? Are the points adjusted (do they open and close)?

Okay so far? Check for fuel. With Webers, it's relatively easy. Remove the air filter housing. Using a flashlight (not an open flame), look into each carb throat. There should be a squirt of fuel each time you open the throttle. No squirt? This may indicate no fuel in the float bowl, ergo no fuel from the fuel pump. Fuel pump shouldn't continue running with the float bowls full. Check the gas gauge for sufficient fuel.

Let us know what you discover.

Sherwood
http://members.rennlist.org/911pcars

[jond911]

Thanks folks...

I'll give these other things a try in the next couple of days and let you know what I discover. I've never noticed a distinct whine from the permatune unit, it is several years old. I believe Permatune is now located here in Wylie, Texas ....a suburb of Dallas. My unit has a California location listed on the label. Model type just says "911". I am aware that there are now different variations of the Permatune.

I'm also running a "tacet" OR is it "facet" square fuel pump. It, to the best of my knowledge is always running and has a distinct "whir" to it. I run the fuel pump in combination with one of those "dial" in pressure regulators and keep it pretty much at about a 2.5 setting.

I'm sure with the help of this forum, I can get this issue resolved before it gets to damn cold in my garage.

Thanks again...

[Zeke]

Facets have a fast clicking sound or *pumping* sound. And, IMHO, they are not good enough for your car. Get another kind of pump that can keep up with the demands of your engine when you drive hard. I know that has nothing to do with your problem at hand, but for the future....

I like to go back over recent events to trace the cause of a problem. to me the washing is key. I'm betting on a moisture problem in the dizzy or in the electricals.

[jond911]

I figured I would let this thing sit for a week or two to verify that water was not the issue..... I've actually been busy with other stuff and since it's a beautiful day here in Dallas, I thought I would try a few things.

Bad news...

No spark to plugs.... no whine from the Permatune, however I previously mentioned that I never have heard a distinct whine from the unit. Also no noticeable spark coming from coil??

I'll be the first one to say that I am definitely not a mechanic... I do however own a voltage meter. I'm just not sure where to start. This is the most difficult task that "she" has given me in 8 years of ownership..

Any thoughts or suggestions on how to proceed would be greatly appreciated...

bump...

Thanks

jond

[jeff m]

Hopfully there is a diag above.

Your points should give a "flashing ground" to terminal C of the non whining permatune.
Terminal B should be car voltage (12v +)
Terminal A is the output from the permatune it sends a 300 dc volt pulse to the transformer (coil) (after each ground pulse from points)

Could be just your points closed up. It is much easier to adj points with dist pulled out. remember to TDC it first.

Jeff

[pwd72s]

Permatunes don't whine...good or bad, no whine.

[jond911]

No whine... I'm in for a challenge here....

I think I've got the above diagram in one of my books around here. Should I try to check the high voltage coming off the permatune while someone is turning the key....with the starter cranking??

[jeff m]

Yes, you can check the 300v at the terminal on the coil while someone cranks the engine.
I use a 600volt neon on two crock clips to test the output.

Don't expect to see 300 volts on your meter as it is not a constant voltage. Any reading over 100 at starter revs is ok.

If you get nothing go back to the permatune and unplug it.
Check for 12v on B.
Check for continuity (200ohs scale) from C to the piggy back on distributor, should read zero or close to zero
Check continuity from A to coil. should also read zero.

Now test in the permatune socket. It's a bit awkward I know.
Check continuity between B and C you should get 100ohms.
If you don't get that 100ohms.
Repost
Good luck
Jeff

[jeff m]

Just remembered an easier test.
If you have a test lamp, pick up 12 v from the middle fuse on left side of enginf bay put test lamp probe on piggy back of distributor and get someone to try to start the car.
It may start so make sue test lamp wiire is away from moving bits.
post result
Jeff

[Evans, Marv]

I had a very similar thing happen with my '72. I turned out to be a poor coil ground contact/wire. Replaced the coil ground with & it started & ran normally. If this turns out to be the problem, you're lucky & it's an easy fix.

[Leland Pate]

I bet your coil is bad.