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Old Jun 5, 2018 | 10:39 PM
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Default SBC running question

Ok guys this for the engine in my daughter's 77 Monte Carlo which is keeping me from getting on to Giddy Up Go! This MUST stop. There appears there may be several problems, but I am perplexed. General story, and I will try to upload a video of it running. Engine is a 305 with an Edelbrock 550 cfm on dual plane intake. It is cammed, , not sure of specs, but not real hot. Tranny is a B&M turbo 350 with a shift kit, standard torque converter. Has headers. All vacuum lines hooked up. New distributor -all new guts hei. Engines idles nicely at 600 rpms. Revs up fine, no real problems. Occassionaly will sit and idle for like 10 minutes, and then for no apparent reason, shuts off. Restarts immediately no problems. Sometimes will shut off again in a few minutes but not always. Early on put it in gear, takes off no problem. Drove it to local school about five miles away, overall ran fine, -really good at 80mph. Did a uturn in school parking lot, stopped and told someone there we were trying to get ready for a car show, and it cut out (quit running). Restarted, put it in gear, quit running. Did that four times. Began to crank a bit hard, almost like not in time. Then caught, started and gave it bit more gas, put it in gear, and away we went. Five miles back. No hesitation, runs great at 80, no problems. Slow down to make left hand turn into the driveway, it stalls out. Repeat performance of restarting like at school. Pull up in front of garage door, idles fine, no problems. Put it in reverse to move and park else where, it stalls out as soon as putting it in reverse. Does that 5 times. Becomes increasingly difficult to start. Coast backward enough each time I get where I want to be, put it in drive pull forward without it stalling shuts of as I get where I am about to put it in park. IN disgust take out keys and quit for the night. At the end of my skill set. Any ideas or help? Thanks Gotta get this done so I can get back to the Vette. BTW we have named the Monte Miss Obstinate because it has fought me step of the way. TIA
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Old Jun 5, 2018 | 10:59 PM
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Is the ignition HEI? The modules can do crazy stuff when they begin to fail.

Otherwise I’d be looking for a loose wire in the ignition somewhere.
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Old Jun 5, 2018 | 11:03 PM
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Distributor is HEI, brand new and so is the module and everything else. Also carb was just rebuilt by "the go to guy" around here who sets up a lot of sprint cars for Knoxville raceway and several dirt tracks and recommended by local hot rodders.
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Old Jun 6, 2018 | 06:31 AM
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Bump the idle up to 800-1000 and see if it still stalls. 600 is really low.
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Old Jun 6, 2018 | 06:40 AM
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New parts are not necessary good parts.
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Old Jun 6, 2018 | 08:48 AM
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New distributor has bad parts in it. Go find GM parts and try again.
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Old Jun 6, 2018 | 10:45 PM
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Like they said.....check for loose/broken wires first. While it's running wiggle the engine wiring bundle to see if it will stumble/stall....same thing under the dash and at the fuse block. If it doesn't have the bright blue cracking spark when you hold the spark plug wire about 1/2" from the spark plug somethins' failing.

I had a similar problem with a new distributor.....I put the original GM HEI dist. back on the car and it ran perfectly.

EEEElectricity......who knows?

Last edited by doorgunner; Jun 6, 2018 at 10:50 PM.
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Old Jun 6, 2018 | 10:56 PM
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One advantage I have in having almost the exact same sbc in three of my cars is that I can swap out a suspected bad part with one from one of the other cars. Can you swap out the distributor, and/or possibly coil from your Corvette?
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Old Jun 7, 2018 | 12:50 AM
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Originally Posted by doorgunner
Like they said.....check for loose/broken wires first. While it's running wiggle the engine wiring bundle to see if it will stumble/stall....same thing under the dash and at the fuse block. If it doesn't have the bright blue cracking spark when you hold the spark plug wire about 1/2" from the spark plug somethins' failing.

I had a similar problem with a new distributor.....I put the original GM HEI dist. back on the car and it ran perfectly.

EEEElectricity......who knows?
Which end of the spark plug do l hold?
One of the first lessons Daddy taught me. Say, I haven't taught Thad that one yet!! Hey Thad... Come here I need some help! Tony said hold the spark plug...….
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Old Jun 7, 2018 | 12:52 AM
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Originally Posted by lowbuck72
One advantage I have in having almost the exact same sbc in three of my cars is that I can swap out a suspected bad part with one from one of the other cars. Can you swap out the distributor, and/or possibly coil from your Corvette?

Well, the Vette isn't running, but I am sure I can find another distributor around here somewhere. Will put that in the troubleshooting order. Start easy and go to the more difficult. Will keep you posted.
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Old Jun 7, 2018 | 12:54 AM
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Originally Posted by PainfullySlow
Bump the idle up to 800-1000 and see if it still stalls. 600 is really low.
Will try that first. It is the easiest. Thanks
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Old Jun 8, 2018 | 07:08 AM
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Even though its new, the coil could be bad. I had a problem with mine cutting out and stalling when the coil got hot. Ran perfect when cold but would stall on the highway. Sat roadside for a couple minutes and it started right up and took off down the highway like nothing was wrong. Sometimes it would quit again five miles down the road and had to repeat the whole process. Then I changed the coil and have had no problems since.
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Old Jun 8, 2018 | 10:28 PM
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A.T. My car idled great...I let it warm up a few minutes (95* outside)….backed into the street....it began idling a bit rough but took off fine...made it about 50 yards....it died.....let it sit 5 minutes....started fine.....began rough idling in a couple minutes....died several times trying to get back to my house......let it cool down....it was producing a yellow spark about 14" long with plug wire held near plug.....died again in garage.....tested spark again/NO spark at all

You know the rest.....didn't go to the paint shop (again).
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Old Jun 9, 2018 | 01:18 AM
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my vote is for distributor issues...bad coil, hei module or the thing under neath that looks like a castle turret I forget what its called.

put in a different known good distributor and see if all the problems go away.

you know my buddy once had crude that would float up and block his fuel line until the car stalled and it fell out of the gas line...until it got sucked up again.....again and again and again it drove us nuts.....

Last edited by bobs77vet; Jun 9, 2018 at 01:18 AM.
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Old Jun 9, 2018 | 01:39 AM
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Originally Posted by doorgunner
A.T. My car idled great...I let it warm up a few minutes (95* outside)….backed into the street....it began idling a bit rough but took off fine...made it about 50 yards....it died.....let it sit 5 minutes....started fine.....began rough idling in a couple minutes....died several times trying to get back to my house......let it cool down....it was producing a yellow spark about 14" long with plug wire held near plug.....died again in garage.....tested spark again/NO spark at all

You know the rest.....didn't go to the paint shop (again).
Oh no my car infected yours! Let me know what you find Tony!
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Old Jun 9, 2018 | 01:41 AM
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Originally Posted by bobs77vet
my vote is for distributor issues...bad coil, hei module or the thing under neath that looks like a castle turret I forget what its called.

put in a different known good distributor and see if all the problems go away.

you know my buddy once had crude that would float up and block his fuel line until the car stalled and it fell out of the gas line...until it got sucked up again.....again and again and again it drove us nuts.....
Thanks for the vote and extra tidbit! Will keep that in mind!
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Old Jun 9, 2018 | 02:59 AM
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Not finding many Genuine AC Delco modules out there. HAs anybody used a Petronix flamethrower? Other brands that have worked well?
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Old Jun 9, 2018 | 03:08 AM
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I put the Pertronix conversion kit in the 1970 4 yrs. ago and no issues.........or point adjustments any more
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Old Jun 9, 2018 | 06:47 AM
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I would not rule out carb float level, what carb?
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Old Jun 9, 2018 | 08:50 AM
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Pertronix Flamethrower kit IS the parts that caused me the pain!!!! Never again!
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