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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Tazman on March 30, 2017, 11:04:40 pm

Title: Bad distirbutor?
Post by: Tazman on March 30, 2017, 11:04:40 pm
Does a distributor go all of a sudden or are there signs to look for? I ask because when my TBI 350 gets warm the tach will fluctuate under load.
Title: Re: Bad distirbutor?
Post by: VileZambonie on March 31, 2017, 05:56:28 am
Curious why you think the distributor is at fault? Is just the tach malfunctioning?
Title: Re: Bad distirbutor?
Post by: hatzie on March 31, 2017, 09:52:11 am
HEI distributors don't "Go Bad".  If there are issues you can repair or completely re-build them to last another 40 + years for not much more than the cheap Chinese rebuilds the parts stores will sell you. 
Fluctuating tach after warmup could be several different problems.  Is the Factory tach signal filter still in place?
Title: Re: Bad distirbutor?
Post by: Tazman on March 31, 2017, 05:43:16 pm
Curious why you think the distributor is at fault? Is just the tach malfunctioning?
When it fluctuates the idle changes and can cause the truck to stutter.
Title: Re: Bad distirbutor?
Post by: Tazman on March 31, 2017, 05:44:26 pm
HEI distributors don't "Go Bad".  If there are issues you can repair or completely re-build them to last another 40 + years for not much more than the cheap Chinese rebuilds the parts stores will sell you. 
Fluctuating tach after warmup could be several different problems.  Is the Factory tach signal filter still in place?
No it is an Auto meter tach.
Title: Re: Bad distirbutor?
Post by: Irish_Alley on March 31, 2017, 06:59:09 pm
so what youre saying is the engine rpms are fluctuating and the tach is picking it up. sounds like an electronic issue but it maybe out of the distributor

http://forum.73-87chevytrucks.com/smforum/index.php?topic=29996.0

is it at a certain speed? or only with a hot or cold engine?
Title: Re: Bad distirbutor?
Post by: Tazman on March 31, 2017, 09:55:18 pm
When warm only.
Title: Re: Bad distirbutor?
Post by: Irish_Alley on March 31, 2017, 10:00:11 pm
check engine light on? does it even come on when you put the key in the ignition "on" without the engine running?
Title: Re: Bad distirbutor?
Post by: Tazman on March 31, 2017, 10:56:34 pm
No lights came on during this.
Title: Re: Bad distirbutor?
Post by: Irish_Alley on April 01, 2017, 04:18:50 pm
might have a bulb out. if you can get it working then you might be able to pull a code from it
Title: Re: Bad distirbutor?
Post by: Tazman on April 01, 2017, 07:49:29 pm
I believe the issue has been found. I have a vacuum leak from one of the corners of the intake manifold. So a new gasket will be put in the next free time I get. I will replace the one on the throttle body as well.
Thanks