How do you test for spark

So, truck started this morning drive it 5 miles, stopped when food shopping. Tried to start truck, it would crank, but not start. Removed vacuum hose from brake booster to intake and sprayed starting fluid into intake, but would not start. Must be no spark! So how do I test for spark with these coil packs? Thanks, any help would be great.

 

Remove the coil and the plug. Leave the coil plugged in.
Stick plug into the coil, then the end of the plug on the block. (Or any surface that’s grounded to the block.)

 

Ok, I’m old school and I thought of that way, but I didn’t know if you could do it with a multi-meter. And if there is no spark, where do I go from there.

 

You could check for power to the coil.
But not spark. Pretty sure the ECM sends the signal for spark. I don’t have access to a manual currently. If no one else helps. I will look and see what wire you need to check for power to the coil.

 

Turn the ignition switch On.
Then check the Black/Red wire on the coil for power.
If not, check the 30A AM2 fuse. (It’s probably good)
This doesn’t check spark, only power to the coil.
The ECM grounds the coil to generate spark.

 

Ok, just take a test lamp, stick the point into the red and then black to see if it lites up. If not check the 30 amp Am2 fuse to see if it is blown. Thanks, I’m just trying to understand.

 

I would unplug the coil. Then check the connector.
I don’t like piercing wires if I don’t have to.

 

I had the truck towed back home this afternoon, I just went out, 5 hrs later and it started right up. What is going on, when it is hot, up to operation temp, it will not start. What could I be looking for? Any ideas? I had it do this 2 times, and had it towed 2 times!

 

Most likely a bad starter or a bad ground. Or both.

 

Any codes? Does it crank?

 

Thanks, but it cranks just fine, but will not fire and start, I do not believe it is the starter.

 

No check engine lite, but I do not have a tester to read any codes. I could bring it to auto zone and have them check, but once I shut it down when it is hot, I have no confidence it will start again.

 

Cam or crank sensor? As someone mentioned earlier the ecm grounds the coils… I’m assuming you have a six…If you plan on keeping this truck invest in a decent scanner. Best 150 you can spend.

 

I have 3.4, but if it is the crank sensor, why start when cold and not start when hot?

 

Hey Rachelsdaddy, I see your from southern nh, I live here in Florida, but grew up and have a home in lee, nh, thanks for your help

 

Really frustrating problem, when it’s cold it starts, drive it 5 miles shut it off, try to start it, it cranks great but will not fire and start. Tried starting fluid in intake and still will not start. The first time it died it was the EFI relay, put a new one in, started right up, but when hot won’t start. I’ve had to get it towed twice.

 

That is absolutely the worst.. much rather it crap out good just once. Without looking at a schematic I would assume that either a faulty knock , crank or cam sensor would prohibit ignition. Electronics, sensors and connections are can be temperature sensitive. I have a twerpy 2.7. Wish I could be more help. Buy a scanner. Thank me later. Over and out. Hooksett

 

Thanks for your help, have a great fathers day

 

Hey guys, I think I found my problem, it was a loose igniter connection! Thanks for all your help.

 

Multimeter is too slow. They typically work on an averaging type read out, specifically Root Mean Square (RMS).

Multimeter won't work.