Stalled after Dizzy Cleanup, Won't Start

[wwest]

Pita..@!!!

[timmy2]

Post a picture of your rotor in relation to the mark on the edge of the distributor body when at TDC for number 1.
It should be just about lined up only on the leading edge.

[OsoMoore]

Originally Posted by timmy2

Post a picture of your rotor in relation to the mark on the edge of the distributor body when at TDC for number 1.
It should be just about lined up only on the leading edge.

Sure, I can do this tonight. She seemed lined up properly after the distributor clean up, but I've had it out of the car a few times since the stall out.

[OsoMoore]

Here's how she looks. The leading edge of the rotor is just about right at the mark. She is adjusted to about 7-8 degrees of advance. She has some hesitation if you leave her back at 5 degrees, presumably because her compression was increased in the rebuild 60K ago.

[wwest]

Hmmmm...

Long ago I worked on a 911 that the engine crankshaft pulley was not keyed correctly.

[OsoMoore]

Originally Posted by wwest

Hmmmm...

Long ago I worked on a 911 that the engine crankshaft pulley was not keyed correctly.

It has always been right before, and I've timed valves and such multiple times with it.

[wwest]

Good.

[timmy2]

Dizzy rotor position looks good.
Really the only thing left is to swap out the CDI to rule it out.
Good ground at coil? (Brown/ White wire to engine case.)

[fongce]

Doing this test, do I turn the key so CDI whines, but not turn key to Crank position?

[tirwin]

This one is turning out to be a Click and Clack puzzler. I agree with Dennis. Rule the CDI in or out. I might throw in a new set of plugs while waiting on your buddy. You could do a compression test at the same time to see if you might have something crazy going on like a valve or valves stuck open.

[Farrell]

this ever get resolved? pretty similar to what my car did, now I'm pulling the motor to replace the airbox. what a PITA!!

[OsoMoore]

Originally Posted by tirwin

This one is turning out to be a Click and Clack puzzler. I agree with Dennis. Rule the CDI in or out. I might throw in a new set of plugs while waiting on your buddy. You could do a compression test at the same time to see if you might have something crazy going on like a valve or valves stuck open.

I put some new plugs in two days ago - no dice. My friend with the 80 SC (and it's CDI) lives out a aways, but I am hoping he can come by this weekend. Meanwhile I am feeling a little stumped. I had the battery on charge and will put it back in tonight and do... I don't know what. Poke around a bit more I guess.

Originally Posted by Farrell

this ever get resolved? pretty similar to what my car did, now I'm pulling the motor to replace the airbox. what a PITA!!

So far no definitive sign it is the airbox's fault. Hopefully I don't need to do that. I had an engine drop last year to rebuild the transmission.

[wwest]

The airbox CAN be replaced without an engine drop.....


How can the CDI be at fault when there is a healthy spark both at the coil and downstream of the dizzy while cranking the engine?

[wwest]

Originally Posted by OsoMoore

I pulled cylinder 4's wire and it had a nice blue spark when cranking. I pulled 4's injector and it smelled lots like gas.

We cranked and it had a fuel spray.

Should this have been the case while cranking, the fuel metering plate fully closed?


I also had a backfire as soon as we did the crank with the injector out. Nearly made me fall over - so loud! Airbox seems fine - popoff valve doing its job?

I didn't get time to inspect the spray too carefully because I was busy almost falling over. It happened immediately on crank with the injector out.

I put the injector back in and it still just cranks with no ignition.

Maybe I'm lacking air? And when we pulled the injector now it could ignite? Heart rate is still coming back down from that noise 1 foot from my head.

It is my understanding that during cranking the "start" injector should be the only source of fuel feed....


LOUD/STRONG backfire!

The pop-off valve can only do so much. Plus, how does one verify, know, that it works in ALL cases?

Flooding the engine all this time?

[wwest]

Originally Posted by OsoMoore

I have new plugs in now, no difference in behavior. I cranked it for a few seconds before I started changing them out.

They all smelled like gas and had some dampness when I pulled them out.

I pulled a fuel injector (with the airbox and all together), and ran it into my glass bottle. It left gas behind there! I was the one doing the cranking so I couldn't see the spray pattern. If the injector is spraying, does this mean the fuel metering plate is moving?

Should here have been fuel in the bottle with just cranking?

Battery is now back on the charger inside the house. All this cranking the starter has resulted in it notably having less power.

The old plugs were a little dirty but not that bad. Number 3 (driver's side forward?) had some heat discoloration on it. I'll keep poking and looking for vacuum issues, but I'm not sure exactly what else to do. No cracks in sight, all hoses I've found seem snug.

Next maybe I can check the spark on each spark plug wire. Previously I had checked spark at cylinder 4, and later at the coil. Although that will result in a fair bit of gas getting into each cylinder unburnt.

Someone know for certain..???

[wwest]

Long. but well worth reading...

Post # 9, Peter Zimmerman.


CIS Pop-Off Valve - Rennlist Discussion Forums

[OsoMoore]

Originally Posted by wwest

It is my understanding that during cranking the "start" injector should be the only source of fuel feed....


LOUD/STRONG backfire!

The pop-off valve can only do so much. Plus, how does one verify, know, that it works in ALL cases?

Flooding the engine all this time?

Presumably when I cranked and didn't start, it was flooding. I tried to not crank for very long, and to leave long gaps between attempts. I presumed the fuel dissipates if left sitting, right?

I'm not familiar with the "start injector", I should probably do some reading on exactly what that is.

[wwest]

Originally Posted by OsoMoore

Presumably when I cranked and didn't start, it was flooding. I tried to not crank for very long, and to leave long gaps between attempts. I presumed the fuel dissipates if left sitting, right?

Yes, but if the CIS is dumping fuel into each cylinder simultaneous with the cold start injector then each time you crank then you get a TO RICH mixture instantly.

I'm not familiar with the "start injector", I should probably do some reading on exactly what that is.

Your engine has a cold start SYSTEM, not just a cold start FUEL injector but an idle AIR bypass around the throttle plate.

"Cold start injector"

Near the bottom of the 6th paragraph:


CIS Pop-Off Valve - Rennlist Discussion Forums

[OsoMoore]

My good friend Arthur came out with his '80 SC and we had a morning of wrenching away. After trying many things, we finally tried a CDI box swap.

With my stuff, when we advanced to about 15 degrees (full advance) we had consistent "putt" noise but not quite a start. There were no other unusual noises. We cranked for a while like this as we tried other things.

When we switched CDI boxes to a known good one, it started right up. After about 20 seconds, the belt or alternator started to squeal, similarly to a low battery putting the alternator under load, but much louder. Surprisingly loud. We turned it off immediately. Afterwards, the base of the fan was quite hot, around the pulley, and I nearly burned myself on it. We had been cranking the engine while trying other things for most of the morning, but I hadn't noticed earlier, even while turning to TDC many times. So I suspect (although I can't be sure) that it got hot only and quickly when it started running.

Last month, when working on the distributor and after it started running again, we had a fairly quiet harmonic sounding noise that was similar in nature to the new squeal. It used to start happening from time to time after the car had warmed up. (See my earlier thread on the noise Engine "Woo Woo" Noise).

Here's a picture of the fan. I'm not sure if that black circle is heat-related. We checked and the belt is not rubbing anywhere, nor is the fan touching the housing at all. I took off the belt and she spins freely. There is a tiny tick noise when she spins, but no notable resistance.

[wwest]

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