[gto4evr]

morning update:

car fired up so fast I barely heard the starter start to turn. it never started this quick even after the "okay to restart once hot" path it's been on awhile. I knew I wasn't imagining it last night! I shut it back down immediately so it wouldn't get hot so I can try it again later when we get back from the trails this afternoon but I'm pretty confident this just solved it. Thanks again to all for the info and ideas!

[gto4evr]

afternoon (and final) update:

repeat of this morning, it's insta-starting now. Thanks again to all!

[HoneyHush]

Good to hear, glad you got it figured out.

[NeighborsComplaint]

I had something like that going on after swapping a one wire alternator. I could hold the key on "start" and the engine would just crank with no fire . My natural reaction was to return the switch to off and try again. Just by chance, I released the key quickly to "run" and the second I released the key to run, it started. Bypass wire install took care of it.

[taktikian]

So am I correct in assuming the coil was the culprit? If so, is there is there a good points coil than members can recommend that mounts in the factory fashion?

[Kenth]

ACDelco U505 is a good replacement coil.

[Greg Reid]

I think that may be the first time I've ever heard of an electrical part that worked better hot than it did cold. Not saying that it didn't happen or that you're wrong, just the first time I've heard of it happening.

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[gto4evr]

Originally Posted by Greg Reid

I think that may be the first time I've ever heard of an electrical part that worked better hot than it did cold. Not saying that it didn't happen or that you're wrong, just the first time I've heard of it happening.

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Greg, I'm leaning towards it worked the same both hot and cold and it's just easier to maintain a warm motor with weak spark than getting a cold one started apparently. totally turned my diagnostic skills up on end though, so much for checking for spark and ticking the box to move on to the next potential culprit. 35 years of messing with these cars and I'm still learning new stuff. I was sure it had to be carb related after ruling out spark and spent way too much time screwing with the choke when this first became an issue. Biggest roadblock was test time, only getting one shot at it a day because once it fired, it would always restart okay. it also dragged on mostly because I barely drove the car anyways last year with all the local cruises shut down except one that had a limit of 50 people (so only 25 cars if 2 people per car) and no spectators so it was kinda pointless to go.

In the course of chasing through this I also found the vac advance wasn't working so that got fixed two weeks ago. I knew it had nothing to do with the start issue but was a secondary problem. Now that both are fixed, this car's actually fun again!

[SRR]

Originally Posted by gto4evr

morning update:

car fired up so fast I barely heard the starter start to turn. it never started this quick even after the "okay to restart once hot" path it's been on awhile. I knew I wasn't imagining it last night! I shut it back down immediately so it wouldn't get hot so I can try it again later when we get back from the trails this afternoon but I'm pretty confident this just solved it. Thanks again to all for the info and ideas!

I just knew it was the coil. When this happened to me it drove me crazy.

[JSchmitz]

Glad you got it fixed. These cars will make you question your sanity at times!

[Greg Reid]

Originally Posted by gto4evr

Greg, I'm leaning towards it worked the same both hot and cold and it's just easier to maintain a warm motor with weak spark than getting a cold one started apparently.

That's a real good point and sounds very possible.


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[FHummel]

The Rochester quad is not usually that fussy, but the adjustment is reasonably critical. I have rebuilt several of those over the years dating back to 1972 on a 1971 455 HO, and never had a problem. Recheck (very carefully) the cold setting of the choke. After not more than 2 pumps of the accelerator, check the setting on the choke plate according to the rebuild specs. Then, looking into the carb at the accelerator shot, pump the gas just once to see if it is actually pumping. If so try to start the car, but do NOT pump the accelerator again. If all your settings are correct it should start fairly quickly. Don't know what else to tell you at this point.

Based on the fact that the car runs well after it does start indicates(to me) that there is an adjustment problem with the choke. Just my thoughts. Good luck - sounds like a nice car.

Well, had I read further I would have seen the problem had been resolved. The coil did not enter into my mind as a possibility. Good job guys!

But here is a problem I had with my 1971 GTO when out in the boonies fishing. Got back to the car and it would not start. There was NO spark at all. My first thought was it is in the distributor and while looking at the points when cranking there was no spark across them. I thought it could be the condenser, but where was I going to get one since I was miles from any parts store. To cut this short I removed the noise suppressor condenser from the fan motor to the heater and installed it in the distributor. Fired right off and I drove home. Both of those condensers are the same ufd (micro farad) and physical size, so no problem interchanging them. The one from the distributor turned out to be shorted. I had never seen one do that before nor seen one since. I have worked on many Pontiacs over the years - mostly late 50s up through mid 70s. Still drive the great ones (Pontiacs) though last built in Australia - 2008 G8GT, 2009 G8GT and a U. S. built 2009 Solstice GXP. Great cars!

[tekuhn]

Originally Posted by gto4evr

okay, before I hit the submit button on this I just went back out there again to try something else and now I'm more confused.

I removed the coil wire from the coil and turned the key on. I see 12v. if I touch the wire to the coil where it's supposed to mount, it drops to 7v.

shouldn't I only be seeing 7 from the ignition in the run position or does it need to ground through the coil for the resistance factor in the wire and without a load it floats up at 12v?

You are correct and that observation was totally normal. The measured voltage is a function of the drop across the resistance wire which varies with the current draw. With the wire disconnected from the coil and zero current flowing (except the miniscule amount drawn by the meter), the voltage drop was zero, but with the coil connected (and the points closed), the current flow dropped the voltage by 5 volts across the resistance wire.