greenjt

EDIT- UPDATE #1: Thanks for the replies guys. I made it out to the garage and started the car. It wasn't happy and ran very rough and wanted to stall - CEL intermittantly on. I pulled the ignition switch on the rear coil (nearer the back of the car and connected to the left distributor) and the there was no difference. I then pulled the ignition switch on the forward coil (connected to the right distributor) and the car purred like a kitten and no CEL. I thought the primary distributor was the one on the right and if so, it would seem like the problem is not the belt. Am i wrong on the primary/secondary? Thoughts on diagnosis??
jg


So on my commute this morning the belt warning light and buzzer came on. I immediately pulled over to check the engine and nothing looked out of place. I turned the car off and restarted - the warning did not come back. A few minutes later the Ceck Engine light came on. Car still running fine.

A few minutes later when i got into traffic i experienced intermittant hesitation under throttle but fine at idle. Pulled into parking garage, checked engine all seemed fine.

I have a morning full of conference calls and can't get back out to the car for another couple hours. When i get back out there my plan is to check the distributor belt by pulling the primary ignition switch and seeing if the car runs. If it runs, does this rule out the belt?

Also, if it is the belt, can i pull the secondary ignition switch and limp home the 20 mile commute?

Thanks.

Fred's 964

James, pull the primary coil wire out of your primary (right) distributor. If the car will run on the secondary distributor, the belt is intact. If it is broken, it will not run and may backfire. If it is broken and you want to drive it home, pull the secondary coil wire for the drive home or else one of the secondary plugs will fire twice each crankshaft revolution and may cause that cylinder to ignite fuel on the wrong (intake) stroke. That should get you home. let us know what you find.

Wachuko

Also, belt light coming on could just be the tensioner sensor... that would explain the light coming on but not the rest of the things your car is going thru...

Are the belts in place and intact (A/C and Alternator Belts not distributor belts) ?? Hesitation could be alternator problems (but you are not seeing lights for those...), cracked distributor caps or rotors...

Do the tests Fred mentions to rule out a broken belt distributor. Let us know how it goes.

Indycam

Fred's 964
"pull the primary coil wire out of your primary (right) distributor."
Thats not the safe way to do it . The way greenjt said he was going to do the test, " pulling the primary ignition switch" , is the safe way and the quick way .

"Also, if it is the belt, can i pull the secondary ignition switch and limp home the 20 mile commute? "
Yes you could but the reward / risk is bad . A tow truck is cheap for 20 miles , no ? I guess an 02 Explorer XLT would be more than good nuf to pull a 964 .

Smokin

James... Let me know if you want the interface back to diagnose anything. I can have it back to you in a day or two.

greenjt

Rick you must have read my mind... I just may take you up on that depending on how things go. Right now i just want to figure out the best way to get the car home.

springer3

The warning light is for the alternator belt. There is no warning light or alarm for a broken distributor belt.

It is possible your other symptoms are due to low voltage. The fan will turn even with a loose belt, but it will slip at the alternator pulley. How tight does the alternator belt feel? When was it last changed?

greenjt

Sorry... meant to include that the other belts appear and feel fine. and the belt warning lightnever came back on after the first restart. just the CEL

MarkD

Easy check for dist belt is to remove the secondary dist cap and try to rotate the dist shaft. If it moves, it's broken.

amfp

Check the belt tensioner pulley. This is the one you can move back and forth when the engine if off. I know with mine, it sticks sometimes, and it sends off the CEL.

Fred's 964

Indycam, I thought pulling the coil wire would be the quickest and simplest test not knowing greenjt's experience level, but I stand corrected if he can easily disable the coil. Where is the primary ignition switch? Also, what would be the risk to the engine in driving it home on one distributor? With the faulty one disabled, wouldn't it run normally at low to moderate RPM? I agree there would certainly be a risk of not making it home if the problem was elsewhere. I'm not new to engine ignitions, but am new to Porsche's and willing to learn the P-car tricks. Thanks for the information.

MarkD

I'm not sure if you are still trying to determine if the dist belt is broken but if you are...
again, just pop the secondary dist cap and try to spin it. Easy!

Fred's 964

The way you describe it, disabling the primary distributor clears it up. That would mean the belt is intact to the secondary. The problem seems to be in the primary ignition system. I would look at the cap and rotor first (for damage) then I would try switching the ignition coil leads to role out the primary coil (after you get it home.) Indycam, what do you think? Are the coils interchangable?

Indycam

"It wasn't happy and ran very rough and wanted to stall - "
Plus
"pulled the ignition switch on the forward coil (connected to the right distributor) and the car purred like a kitten and no CEL. "

Makes me think that you have something amiss ( a bad pun , sorry) in the other side . A leaking spark jumping to a cylinder at the wrong time . Or maybe a bad ingnition switch . Do you know about switching parts from a to b to see whats messing up ? Hows your rotors look ? Caps ?

Indycam

"Are the coils interchangable?"
Yes they are . just move the wires from one to the other . No big deal .

"I thought pulling the coil wire would be the quickest and simplest test"
With the motor running you can reach in and unplug one of the two switches and then plug it back in . Move to the other switch and do the same test . Takes 30 secs max . All very safe .