Testing spark and injection pulse...without running engine?
Thread Starter
Teching In
Joined: Mar 2009
Posts: 30
Likes: 0
Testing spark and injection pulse...without running engine? Hey all!
I have a 2005 CTS-V (LS6) and I'm doing some engine testing just to test the general health of the car.
My question is hopefully simple:
I've wired a remote starter switch to the starter so I can turn over the engine without an issue.
The reason that I don't want to test these with the engine actually running is that I've disconnected my fuel lines and won't be able to actually pump any gas into the engine (I can reconnect everything if necessary). In addition, I'm only able to work on the car after 9pm and my 15mo sleeps above the garage.
So...will it be a problem to test spark/ignition-pulse with just the remote starter switch and not actually running the engine with gas? Will it be bad to crank the engine repeatedly using the starter and not actually running the engine?
Thanks!
I have a 2005 CTS-V (LS6) and I'm doing some engine testing just to test the general health of the car.
My question is hopefully simple:
- Can I test spark without the engine actually running?
- Can I test the injection pulse (using noid lights) without the engine actually running?
I've wired a remote starter switch to the starter so I can turn over the engine without an issue.
The reason that I don't want to test these with the engine actually running is that I've disconnected my fuel lines and won't be able to actually pump any gas into the engine (I can reconnect everything if necessary). In addition, I'm only able to work on the car after 9pm and my 15mo sleeps above the garage.
So...will it be a problem to test spark/ignition-pulse with just the remote starter switch and not actually running the engine with gas? Will it be bad to crank the engine repeatedly using the starter and not actually running the engine?
Thanks!
You might pump the lifters down so the motor is very noisy when eventually restarted. I have tested injectors with a testing unit, but the one I have requires fuel pressure because it uses the pressure drop as part of the test. Not sure what "noid lights" are.
On The Tree
Joined: Jun 2015
Posts: 182
Likes: 3
From: Portland OR
A "NOID light" is a marketing term for a small LED test light that plugs into an injector connector.
As long as there is oil in the motor and it is making oil pressure, crank away, you won't hurt anything.
Just a remote starter is not going to do much, you need to power up the PCM and the rest of the system.
As long as there is oil in the motor and it is making oil pressure, crank away, you won't hurt anything.
Just a remote starter is not going to do much, you need to power up the PCM and the rest of the system.
Thread Starter
Teching In
Joined: Mar 2009
Posts: 30
Likes: 0
Ok - another noob question then.
Can I "hot-swap" the injector electrical signals and spark plug wires while the engine is running?
And by this I mean - if the engine is running (not just cranking, but actually running), is there any concern with popping off the injector electrical terminals one-by-one and testing that a pulse is present with the noid light? I'd reconnect each injector signal after confirming the pulse is present.
Same thing with spark plugs - can I safely remove the spark plug wire and test with my "spark plug tester"?
Can I "hot-swap" the injector electrical signals and spark plug wires while the engine is running?
And by this I mean - if the engine is running (not just cranking, but actually running), is there any concern with popping off the injector electrical terminals one-by-one and testing that a pulse is present with the noid light? I'd reconnect each injector signal after confirming the pulse is present.
Same thing with spark plugs - can I safely remove the spark plug wire and test with my "spark plug tester"?
TECH Junkie
Joined: May 2012
Posts: 3,047
Likes: 713
From: Poplarville, MS
Yes you can test the injectors that way with the engine running. As for testing spark, I would hook the spark tester to the plug wire before starting the engine. If you try to hook the spark tester up with the engine running you will most likely get shocked.
