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1956 4dr Wagon. 2009 Corvette
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192 Posts
Discussion Starter · #1 · (Edited)
Problem solved. The ignition module was not programed correctly from the factory. It was set to run on the older Petronix system not the Multi-Spark CD system. Idles much better and I can set the timing correctly now. Vacuum advance is working just like it is supposed to.

Thanks

BLUF: When I connect vacuum to my distributor the engine coughs and immediately dies. Doesn't matter where I have the base timing set. If I connect to ported vacuum on the carb it will pop and die upon acceleration. Seems to be running fine without the vacuum advance hooked up. Total timing is about 34. No detonation issues.

Fresh 383 stroker quality build. Full roller L31 engine. Edelbrock carb and intake. Smooth idle torquer camshaft. All the latest Pertronix multi spark ignition system. Started right up the first time I tried it after the build.

Called Petronix. Guy was nice but had no idea. Took the time to go thru all the base setting for the electronic module, everything was fine. Just wanted to send me a new vacuum module.

Just tried a new distributor - same issue. (Same Petronix model).

I'm in constant pain and probably not thinking clearly. I am having knee surgery next week - yea!

What am I missing? Does seem to run fine without the vacuum advance but shouldn't work as advertised?

Good news is that I can see the light at the end of the tunnel for this winter project. Kept my 3 on the tree and overdrive, running 3.73 gears. Rebuilt them both. Quite and rolling smooth. This engine has so much torque. Feels like the car weighs nothing now. Only need not even 1/4 throttle to drive safely. Got to watch the throttle operation so I don't break the drivetrain. Vintage air install in the works right now. Man that evaporator was tight but its in! Now all the small stuff.

Thanks in advance. Help please....
 

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1956 4dr Wagon. 2009 Corvette
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192 Posts
Discussion Starter · #3 ·
Is that total timing with or without vacuum hooked up? I would run it with ported and combined with total of 32* at about 2500-3000 rpms.
Without vacuum hooked up. Can not hook up the vacuum - dies on me. When I connect to ported it pops, cracks and dies when I try to open the throttle. I haven’t tried using the timing limit pieces for the mechanical advance.


Thanks
 

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🐔County, TN. 55 Bel Air Sport Coupe
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If you are holding the vacuum hose with the end open, not on the distributor, does it still idle? What about if you hold the hose pinched closed? I'm thinking you could have a large leak in the hose or a leaking vacuum canister. Speaking of that, if you have power brakes, try blocking off that vacuum also and see how it acts.
 

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1956 4dr Wagon. 2009 Corvette
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Discussion Starter · #5 ·
If you are holding the vacuum hose with the end open, not on the distributor, does it still idle? What about if you hold the hose pinched closed? I'm thinking you could have a large leak in the hose or a leaking vacuum canister. Speaking of that, if you have power steering, try blocking off that vacuum also and see how it acts.
No vacuum leaks. The problem occurs when I apply vacuum valve on the distributor. The vacuum valve is good. Holds vacuum and moves the plate in the distributor. Not sure what you mean by power steering? Maybe power brakes? I don't have vacuum going to anything else right now. Engine runs/drives smooth until I try to hook up the vacuum line to the distributer. Thanks
 

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Only a suggestion if you have the multi spark box can you connect the distributor without using the multi spark directly to the coil set your base timing at let's say 12* then try with & without the vacuum line either ported or manifold & see if it still does the same & at how much advance. I'm familiar with the distributor but not they're multi spark ignition.If your engine is using vortec style heads it may want a little less timing but certainly wouldn't cause your issues.
 

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Discussion Starter · #7 ·
Only a suggestion if you have the multi spark box can you connect the distributor without using the multi spark directly to the coil set your base timing at let's say 12* then try with & without the vacuum line either ported or manifold & see if it still does the same & at how much advance. I'm familiar with the distributor but not they're multi spark ignition.
Good idea! I will give it a try. Should be an easy test. Thanks
 

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No vacuum leaks. The problem occurs when I apply vacuum valve on the distributor. The vacuum valve is good. Holds vacuum and moves the plate in the distributor. Not sure what you mean by power steering? Maybe power brakes? I don't have vacuum going to anything else right now. Engine runs/drives smooth until I try to hook up the vacuum line to the distributer. Thanks
Yes I meant power brakes, I edited it.
 

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Going out on limb here, You say the plate inside the distributor moves and the total timing is 34* That all sounds good. I'm thinking with the movement of the distributor plate is something moving enough to cause a short inside or grounding out, or pulling on a wire and causing a bad connection. or could the plate be moving tooo far and over advancing ??? Also as we have seen many times Don't discount TWO defective "new" parts.
 

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1956 4dr Wagon. 2009 Corvette
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Discussion Starter · #10 ·
Only a suggestion if you have the multi spark box can you connect the distributor without using the multi spark directly to the coil set your base timing at let's say 12* then try with & without the vacuum line either ported or manifold & see if it still does the same & at how much advance. I'm familiar with the distributor but not they're multi spark ignition.If your engine is using vortec style heads it may want a little less timing but certainly wouldn't cause your issues.
Can not independently hook up this distributor. It requires the use of a Capacitive Discharge (CD) or other primary ignition system. I think I will try to turn off the multi spark system and see what happens.
 

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With what I'm seeing, I would try a totally different system. I have a ready to run MSD distributor with a standard coil. Runs perfect like it's supposed and with vacuum advance. Drop it in and go. I never felt the need or complication of a multi-spark ignition. They used to run just fine with the standard ignition, and even points with too many things to go haywire otherwise. I would always doubt my timing light if using CD multi-spark.
 

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1956 4dr Wagon. 2009 Corvette
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192 Posts
Discussion Starter · #14 ·
So, my brand new Petronix 60100 coil may be bad. The digital electronic system is giving me a code indicating a bad ignition coil. Could that be the whole problem???? Replacement is on the way.
 

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1956 4dr Wagon. 2009 Corvette
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Discussion Starter · #16 ·
Do you have a full 12 volts to your coil no running through the ballast resistor?
Yes. It’s a digital electronic system so the power goes to the control box then out to the coil. Problem is solved. The brain box was not programmed correctly. Thanks
 
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