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#1 |
Registered User
![]() Join Date: Jul 2023
Location: Houston Texas
Posts: 11
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After watching too much Uncle Tony's Garage I decided to have a early midlife crisis and buy a classic with a carb. I decided to get a 79 K5 Blazer and am running into some issues with the HEI on it.
Story starts like this. I just got the truck and I go to get her inspected. She turns on and runs like a beauty; mechanic agrees. Car passes inspection and I go to turn it on to head out. For some reason I tried to turn on the car the and it would crank but wouldn't turn on. I talk to the mechanic about it and we saw gas coming into the carb and heard the fuel pump. We decided maybe it got flooded, so I decided to wait around 20 minutes to try and crank again but nothing. At first I thought maybe it got vapor locked because its been around 100 degrees here in Houston but that was not the case. After around 30 minutes me and the mechanic start looking around we test the battery and try again but battery was good. Carb still smells like gas and cars still cranking we decide it's gotta be an electrical issue. He jumps in and starts wiggling the wires on the HEI coil and we notice the cap has been zip tied. After some wiggling around I turn the key and she turns on like a beauty again (SEE PICTURE 1A, Blue circle). We talked a bit and he says probably something is up with that distributor coil wire and recommends I should run an MSD on it. Come 15 minutes later I get home and let the car run for a bit. The drive back was flawless by the way. After a bit in front of the garage car shuts off again. I decide to take a break and go swim because its hot outside. I come back a couple hours later, give the pedal a half pump and turn the key nothing. Pop open the hood and wiggle the wires around on the HEI ignition coil. I crank the key car turns on like a beauty and that's how she is now. So I dug around a bit later and I also noticed a clear tubing that is connected to a fitting off the back of the intake under the HEI Distributor (SEE PICTURE 8 PINK CIRCLE)and runs through the firewall into the cab into what seems like nowhere. The tube also has some clear liquid in it with alot of air (SEE PICTURE 1A, 2 PINK CIRCLE). I was thinking maybe this was some kind of nitrous tubing or something but I'm not sure. It also has a 8k RPM Gauge installed inside Anyways, the situation is I've been thinking about replacing my HEI coil with a Pertronix Flamethrower but I noticed the leads in those are Red and Black/white while mine are red and Teal. Would this be compatible? Also does anybody have an idea why I might have to be wiggling them around? Maybe the coil is fine and the wire installation under the cap just needs to be redone? Lastly what is this random tubing doing around here?! I've been trying to do some research on it but I can't figure it out and it's driving me nuts. Thank you all, Last edited by ladybugblazer; 07-30-2023 at 08:37 PM. |
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#2 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: Question about 350 HEI and Mystery tubing
The tubing is your oil pressure line. Likely runs to your instrument panel.
The power connectors on your hei appear to be the non-insulated type. The power wire contacts the tach wire and results in a no start. The zip tie is likely used to keep that clip in place. It’s not the right clip. |
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#3 |
Registered User
![]() Join Date: Jul 2023
Location: Houston Texas
Posts: 11
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Re: Question about 350 HEI and Mystery tubing
Alright cool I do have an oil pressure gauge running in that same spot so that solves that appreciate it. As for the power wire contacting the tach wire how would I go about preventing that per say? Also do you think I can swap the coil with the MSD or pertronics or should I just leave as is the coil seems to work fine maybe it's just that when they touch its bringing up issues
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#4 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,622
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Re: Question about 350 HEI and Mystery tubing
Should be a bat and tach markings on the plastic cap where the wires are connected.
Try unplugging the tach wire. |
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#5 |
Registered User
Join Date: Oct 2013
Location: Maine
Posts: 2,357
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Re: Question about 350 HEI and Mystery tubing
You can buy a new HEI power plug at the parts stores
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76 Chevy K20 76 GMC K15 77 Chevy C10 77 Chevy K10 |
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#6 |
Registered User
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,548
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Re: Question about 350 HEI and Mystery tubing
The Amazon link shows what the OEM power connector looks like. Notice the U shaped on the top of the red wire? That U shaped piece snaps over the small bump on the side of your HEI dizzy. After many years, that U shaped thing tends to break. The zip tie is probably a quick fix that tried to prevent exactly what happened to you after the inspection.
Get a new wire. Probably available at a local parts store. https://www.amazon.com/Distributor-T...lbWF0aWM&psc=1 |
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#7 |
Registered User
![]() Join Date: Jul 2023
Location: Houston Texas
Posts: 11
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Re: Question about 350 HEI and Mystery tubing
Thank you all this is all great information! I've went ahead and ordered myself a HEI pigtail pair and I'll probably end up replacing the clips on the old with the new ones rather than the wires and seeing where that goes.
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#8 |
Registered User
![]() Join Date: Jul 2023
Location: Houston Texas
Posts: 11
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Re: Question about 350 HEI and Mystery tubing
Update to my situation: I went ahead and cut the ziptie and pulled out the coil wires. They were put into the coil without any clips on them. Seems like the tach wire is new but the pink BAT wire is from the 70's. The pink wire did have an exposed portion near the tip and had a decent bend on it on the end. I unbent it and I attached clips to both pigtails and put them back into the coil. They seem to be holding up pretty good I pulled on them a bit and they were sturdy and the exposed portion of the pink one is now covered up by the clip and seems to be ok.
She fired right up. I will test drive her later and see how that goes! Thank you all |
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#9 |
Registered User
Join Date: Oct 2015
Location: Ottawa, Ontario, Canada
Posts: 752
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Re: Question about 350 HEI and Mystery tubing
The coil cover cap red one is aftermarket does it have the three bolting screws 1 back 2 each side to hold it in place like factory if not then that cap is only held on by the top clip that attaches to the top of a set of spark plug wire boot on the coil side. since he changed wire to universals coil side set that way the zip tie. You can get both parts at any scrap yard off any small block V8 Chevy with a factory 75-86
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![]() Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change. |
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#10 |
Registered User
![]() Join Date: Jul 2023
Location: Houston Texas
Posts: 11
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Re: Question about 350 HEI and Mystery tubing
Thanks Pontiac1976 I'll definitely take a look at that. I ran the car for a bit again today and touched the wires to see if they were hot to the touch and they seemed fine today. Last time when they shorted out they burned my hand.
One thing I do have a question about is the smell. This is my first carbureted car and without catalytic converters at that. Is the exhaust supposed to smell a little gassy? She sounds and seems like she idles fine but I wanna make sure this is normal and if my carburetor is tuned correctly |
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#11 |
Registered User
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,548
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Re: Question about 350 HEI and Mystery tubing
Yes on the gas smell. Smell may vary depending on ethanol vs 100% gas as well. That used to be the 'normal' smell and the sulfur smell out of a cat vehicle was the bad smell.
Once you get the power/tach wires fixed, check your timing. |
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#12 |
Registered User
Join Date: Oct 2015
Location: Ottawa, Ontario, Canada
Posts: 752
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Re: Question about 350 HEI and Mystery tubing
If you're going to tunning your carb. Best tool for tunning the carb big face 4-5" Vaccuum/Fuel pressure gauge. Good to tune carb, test Vaccuum lines, fuel pump, fuel line system.
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![]() Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change. |
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350, blazer, hei |
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