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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: stevens on December 26, 2007, 04:15:27 pm

Title: starts back up sometimes???
Post by: stevens on December 26, 2007, 04:15:27 pm
Alright Im still working with my new motor and trans.. I drive it around all day then sometimes it does not start at all, it turns over just wont fire  :-[ any sugestions on what to check its a 78 mild cam, carb, intake


also the trans only goes in 1 and 3rd and 2ed sometimes, its rebuilt with a shift kit


78 p/u 350/350th 
(built not bought)
Chris
Title: Re: starts back up sometimes???
Post by: jonkmbll89 on December 26, 2007, 07:42:04 pm
Does your distributor have a four prong plug?
Title: Re: starts back up sometimes???
Post by: Fordeatinz71 on December 26, 2007, 08:33:35 pm
sounds like a bad ignition module.  the ignition module is in the base of the distributor under the cap if you didn't know.  it has 2 plugs coming out of it and is held to the distributor by 2 screws.  these commonly fail when they get hot and sometimes resume function when they cool off.  it's important to determine what isn't working when it's not starting.  is it not getting fuel (vapor lock) or is spark not present?  if it doesn't have spark then i would bet money on the ignition module.  if it's fuel, then i'd bet vapor lock. 
Title: Re: starts back up sometimes???
Post by: baggedk5 on December 26, 2007, 09:08:20 pm
The two most likely causes dieseling is usually incorrect timing, or wrong idle speed setting on the carb. Have you checked either?

If it was me, I would start with the timing, its easy and always a good thing to check. If that doesnt solve the problem, check the vacuum adv., then move on to the idle adj.
Title: Re: starts back up sometimes???
Post by: VileZambonie on December 26, 2007, 09:39:31 pm
Hoat soak crank no start is typically a faulty distributor pick up coil.

You'll have to elaborate a little more on your trans shifting problem if you want more than a wild guess.
Title: Re: starts back up sometimes???
Post by: stevens on December 27, 2007, 03:19:44 pm
I replaced the pick up coil, yah I still need to set the timing just need to find someone with a timing light. Thats probly the problem :'(

The trans is rebuilt th350 and it was converted to standered (no clutch) with shift kit, I have a 2500 stall speed and it seams to only shift when you give it alot of gas and it goes in to 1 to 3 

78 p/u 355
Title: Re: starts back up sometimes???
Post by: VileZambonie on December 27, 2007, 06:43:38 pm
See if there's vacuum at the modulator with the engine running.
Title: Re: starts back up sometimes???
Post by: 77c15 on December 27, 2007, 09:42:30 pm
Take Viles advice! I got screwed on a rebuilt tranny because the guy at the shop put a junk mod valve in it and forgot to tighten it down with the hold down bracket and I blew the sun gear, pump, and every gear out of it...all because he wanted to get it done before he went on vacation!