Author Topic: 1978 blazer dies when put in gear  (Read 11393 times)

Offline Mikeymike383

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1978 blazer dies when put in gear
« on: February 27, 2016, 04:32:34 pm »
Idles fine but when I put it n gear it's dies even if I try to give it gas 1978 gmc Jimmy 2wd with org sbc 350 and th350 tranny. Just put a new vac advance on it. I've let it warm up 4 like 5 mins and it still dies
383 stroke

Offline Irish_Alley

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Re: 1978 blazer dies when put in gear
« Reply #1 on: February 27, 2016, 05:48:12 pm »
i would think an improper tune due to a vacuum leak. do you have all your vacuum hoses still hooked up?
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Mikeymike383

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Re: 1978 blazer dies when put in gear
« Reply #2 on: February 27, 2016, 07:44:09 pm »
P.o put a different carb and intake but most stuff is still hooked up or capped off
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Offline Stewart G Griffin

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Re: 1978 blazer dies when put in gear
« Reply #3 on: February 28, 2016, 06:30:15 am »
Well, it's a 78 so no lockup converter......... so that's out.

Offline blazer74

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Re: 1978 blazer dies when put in gear
« Reply #4 on: February 28, 2016, 12:08:15 pm »
Condition of the exhaust.?

Offline FlatBlack77

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Re: 1978 blazer dies when put in gear
« Reply #5 on: February 28, 2016, 01:43:01 pm »
Well, it's a 78 so no lockup converter......... so that's out.

but couldnt it be a sign of a bad converter?

was it running just fine beforehand?
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Offline Irish_Alley

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Re: 1978 blazer dies when put in gear
« Reply #6 on: February 28, 2016, 02:05:14 pm »
i dont think it would cause that much of a problem with being a small vacuum line but unplug the vacuum advance line right at the distributor with the engine running. does the engine speed change?
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Mikeymike383

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Re: 1978 blazer dies when put in gear
« Reply #7 on: February 28, 2016, 11:02:18 pm »
I'll check it in the morning it was running fine and I realized that the vac advance didn't work so I put in a new 1 but didn't drive it. And now it turns off when put in gear. It's a after market dual exhaust system. The guy that put it on did junky welds so I can feel exhaust coming out of a few lil spots. Could it b anything with the carb. The p.o gave me papers with the truck saying it was rebuilt sep 15th 2015. My buddy keeps saying its vapor lock but if it was vapor lock would it idle fine then just die when put in gear. I have a 1976 all org caprice that use 2 do this but it needed the carb rebuilt
383 stroke

Offline blazer74

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Re: 1978 blazer dies when put in gear
« Reply #8 on: February 29, 2016, 04:24:51 pm »
Problem started when u messed with the distributor.

That's where I'd be looking.

Offline blazer74

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Re: 1978 blazer dies when put in gear
« Reply #9 on: February 29, 2016, 04:25:36 pm »
Bone basic on a 78

Offline Mikeymike383

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Re: 1978 blazer dies when put in gear
« Reply #10 on: February 29, 2016, 05:22:43 pm »
Ya maybe it was tune with the non working vac adv
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Offline Mikeymike383

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Re: 1978 blazer dies when put in gear
« Reply #11 on: February 29, 2016, 05:30:38 pm »
I was thinking I actual drove the Jimmy around my apartment complex after I changed it  but that was a few days after I changed the vac adv
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Offline blazer74

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Re: 1978 blazer dies when put in gear
« Reply #12 on: February 29, 2016, 05:38:03 pm »
I'd reset my base timing to 8 to 10 deg and go from there. If this was a running driver.
If not fuel filter first.

Offline Mikeymike383

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Re: 1978 blazer dies when put in gear
« Reply #13 on: March 01, 2016, 12:38:48 am »
Ya I'm going 2 change the fuel filter tomorrow anyway. This is gonna b my daily driver once I'm done fixing the lil problem and doing a full service on it
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Offline blazer74

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Re: 1978 blazer dies when put in gear
« Reply #14 on: March 01, 2016, 12:47:56 am »
You haven't given any history other the vac advance