Grounding Plugs

[Andrec4016]

Here is a real dumb question, I'm planning to do a compression test on my 83 E140 and according to the manual you must ground the plugs, I understand the why but it's the how I'm not certain about, do you actually attach a wire to the plug or spark socked and connect them to ground? wouldn't this cause a short??

 

[Laddies]

Re: Grounding Plugs

You want them grounded to protect the high voltage componets and lessen the chance of fire

 

[Dunaruna]

Re: Grounding Plugs

That's exactly how you do it, jump the plug lead directly to ground. All that does is complete the curcuit, just not through the spark plug. Technically you can call it a short but it's harmless.<br /><br />Aldo

 

[Silvertip]

Re: Grounding Plugs

Since the plugs are removed for a compression check, you obviously don't want spark to occur anywhere near the spark plug holes unless you want to experiment with pyrotechnics (results in singed eyebrows). Two ways to do it 1) remove the wire from the plug and ground it (won't hurt anything). 2) Leave the plug connected, but route it away from the head and allow the metal shell of the plug to be grounded to the block. The plug will fire normally but it won't ignite any fuel being expelled from the cylinder.

 

[Andrec4016]

Re: Grounding Plugs

Upinsmoke, you take the fun out of working on an engine, thanks I thought I was reading that wrong when I saw ground the plugs

 

[Silvertip]

Re: Grounding Plugs

If you have a safety lanyard, you can also remove it which disables the ignition. Or you can simply jump the starter solenoid to spin the engine with the ignition off. Lots of ways to not produce fire.