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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: jonkmbll89 on December 02, 2007, 09:16:23 pm

Title: Ignition firing when it wants
Post by: jonkmbll89 on December 02, 2007, 09:16:23 pm
I have an 85 short bed with a 350. My problem is it only fires up when it wants to. I am getting power to the distributor. I have changed everything out inside the distributor. Today I traced the problem to the box under the dash. I would try to start the motor and when it wouldn't start I would tap on the box and the motor would fire up. I would like to know what the name of the box under the dash ???
Title: Re: Ignition firing when it wants
Post by: Lt.Del on December 02, 2007, 09:31:11 pm
You have an 85, so that rules out a computer.  Do you have a digital camera you can put up a pic.  Where is the box under the dash? by the steering column, heater, under glove box?
My guess would be that your problem is the ignition coil.  Do you get spark at the plugs when it doesn't start?
Title: Re: Ignition firing when it wants
Post by: Fordeatinz71 on December 03, 2007, 12:03:06 am
that "box under the dash" makes me think it's an old alarm system with an ignition interruptor.  it was probably "disabled" but not removed, and now it's malfunctioning and cutting ignition power...
Title: Re: Ignition firing when it wants
Post by: Captkaos on December 03, 2007, 10:23:43 am
It is the ESC (Electronic Spark Control)  Bypass it and you will be much better off:
http://73-87.com/7387garage/drivetrain/escrepl.htm
Title: Re: Ignition firing when it wants
Post by: jonkmbll89 on December 03, 2007, 06:12:27 pm
Bypassing the ESC worked. Thanks Captkaos.
Title: Re: Ignition firing when it wants
Post by: Captkaos on December 03, 2007, 06:15:53 pm
No problem.  That is a common issue.  When those things go bad it is a major pain.