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Username Post: 87 350 sbc engine won't turn off        (Topic#358310)
SgtSnuffy 
Poster
Posts: 3

Reg: 10-04-19
10-04-19 12:52 PM - Post#2777083    

First time postee.
I recently bought an 87 rs 5.7 350 sbc with a lot of issues I plan on fixing. I'm new at fixing vehicles.

One of the big issues I have is the engine continues to run after the key has been removed from the ignition. I have to put it in gear and stall it in order to stop it. I have an 8500 quadrajet as well.

What should I do to fix this issue?



 




Shepherd 
Frequent Contributor
Posts: 2008

Loc: Lake George, NY
Reg: 11-11-15
10-04-19 01:32 PM - Post#2777084    
    In response to SgtSnuffy

Welcome to CT. Is this preigntion run on or the ignition system is still live when the switch is in the off position ? Not enough info so far.



 
SgtSnuffy 
Poster
Posts: 3

Reg: 10-04-19
10-04-19 03:29 PM - Post#2777087    
    In response to Shepherd

The ignition is placed in the off position and key removed.

It is still live in the off position.




Edited by SgtSnuffy on 10-04-19 03:30 PM. Reason for edit: No reason given.

 
Shepherd 
Frequent Contributor
Posts: 2008

Loc: Lake George, NY
Reg: 11-11-15
10-04-19 05:55 PM - Post#2777098    
    In response to SgtSnuffy

Again, when off do you have 12v to the distributor?



 
SgtSnuffy 
Poster
Posts: 3

Reg: 10-04-19
10-04-19 06:56 PM - Post#2777102    
    In response to Shepherd

not sure. How do i check. im very new to the mechanic aspect of vehicles



 
Shepherd 
Frequent Contributor
Posts: 2008

Loc: Lake George, NY
Reg: 11-11-15
10-05-19 04:27 AM - Post#2777110    
    In response to SgtSnuffy

Test lite on the positive terminal of the distributor. You may need to recruit some help with this.



 
paulo57509 
Senior Member
Posts: 424

Loc: Tracy, CA
Reg: 07-18-00
10-14-19 01:59 AM - Post#2777837    
    In response to SgtSnuffy

Please don't be offended, but I have to ask this because in my experience, a LOT of 3rd Gen F-Bodies usually have had a massive amount of hacking done to them, especially to the computer command control, ignition, cooling fans, you name it.

You posted that you have a 5.7L; the '87 RS was a California only thing and only came with a V6. We'll assume there's been more than basic mods in play here.

Let's start with this (as touched on by Shepard):

I'm going to assume your engine has a large cap HEI distributor...looks like this:



Locate the single, pink wire going into the side of the distributor cap (not the one shown in the image)

The pink wire in question is coming from the ignition switch.

The pink wire in question should have 12-volts with the key ON.

The pink wire should have 0-volts with the key OFF.

With the key OFF and the engine OFF, unplug the pink wire from the distributor. Using a volt meter or test light, probe the wire.

The meter/test light should show zero volts/light off.

1987 IROC-Z 5.0L
1992 Lumina Euro 3.1L
2003 GMC Safari


Edited by paulo57509 on 10-14-19 02:00 AM. Reason for edit: No reason given.

 
elcamino 
Dedicated Member
Posts: 5440
elcamino
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
03-04-20 06:49 AM - Post#2787924    
    In response to SgtSnuffy

This reminds of a common thing I seen back in the 70-80's with engines that are carboned up, on the tops of pistons. You could turn off the engine but it would continue to run due to the carbon igniting.

They called it dieseling. Dieseling or engine run-on is a condition that can occur in spark-plug-ignited, gasoline powered internal combustion engines, whereby the engine keeps running for a short period after being turned off, due to the engine kicking back upon shutdown, drawing fuel through the carburetor, into the engine and igniting it without a spark. Built-up carbon in the ignition chamber can glow red after the engine is off, providing a mechanism for igniting unburnt fuel. Such a thing can happen when the engine runs very rich, depositing unspent fuel and particles on the pistons and valves. Similarly, rough metal regions within the piston chamber can cause this same problem, since they can glow red. It has also been suggested that an improperly rated spark plug can retain heat and cause the same problem

Mike
2017 GMC Sierra Denali Ultimate 6.2L / 8-sp Z95
2017 John Deere X738 Snow Blower
2018 Polaris RZR S 900 EPS
2016 Polaris RZR 900 EPS


 




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