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Click/Spark noise after changing spark plugs - 1990 Porsche 944 S2

Need some guidance…
just changed my car’s spark plugs with NGK Iridiums… wires seemed ok so didn’t change them…
It was my first time using a torque wrench. I did set it to 20 ft lbs but stopped before I heard the click sound as it felt tight enough and I didn’t want to mess up the threads…

after starting it, I am hearing a ticking/spark sound…

i bought the plugs that matched my car from Pelican parts. I didn’t check the gap before installing… assumed that they were gapped correctly.

i didn’t torque them to 20 ft lbs as I was scared of messing up my threads… they are in pretty tight…

I didn’t change the existing wires (Beru). Should I have changed the wires that would work with NGK plugs?

i checked the car in the dark while running and I didn’t see any arcs…

this was my first time doing a DIY change… wonder what mistake/s I made…

Go back and make sure none of the spark plugs are loose.


Plugs for this car are pretty deep in. Can’t Check by hand if they are lose or not.
With the wrench, they seem very tight but I will try to tighten them a little more…

Are these the exact stock spark plug for your 944?

No but the are supposed to fit my car… I bought the high performance ones from NGK instead of the stock one from Bosch

You won’t get any more performance, I’d got the stock plugs and torque them to spec.

Got it…
About torque: as per instructions, I should torque between 18-22 ft lbs… I had set my torque wrench to 20 ft lbs. plugs felt pretty tight before I heard the click from wrench… should I tighten till I hear the click?

Is that Porsche’s spec?

#1. Make sure threads are clear and your plugs go in with light “by hand” force.
You do not want to cross-thread them.
You do not want to get plugs into the dirty threads, where you fight against old caked “anti-seize lube”, clean it with acetone or other appropriate solvent if this is the case.

#2. Find Porsche specs (not plugs specs!) and make sure you tightened it properly, not “tad bit before it clicked”, as you do not know the torque until it clicks

Is there any way you can narrow down where the noise is coming from, Listening with a long piece of heater hose is one thought, do not want to be liable for that suggestion though, so at your own risk.

Yes, Porsche specs… 18-22 ft lbs

Porsche specs are 18-22 ft lbs… they went in cleanly and I was able to hand tighten them. Used a wrench to do the final turns…

I guess, will go back and tighten till I hear the click…

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Look at the engine at night and you might see sparks from the wires. It’s fun if you see some.

I did, no sparks or arcs

Time to be brave and touch the wires while she is running. After that I would be looking for cracked plug boots that go down into the plug wells… you can still hear arcing if it is happening down in the plug well.

But for giggles… run your fingers all over the wires while the engine idles… I don’t need to tell you if and when you found the culprit if it is above board and not inside the wells… Lets just say “you’ll know”

We used to throw charged ignition capacitors, and got zapped a few times by ignition, my arm bent seemed to help I guess, the jolt always stopped at my elbow Put sad face emoji here.

I sure do hear you about being “zapped” @Barkydog. However if the OP engages their “Safety Squints” during the test it should prevent any high voltage ignition shocks… the downside is that they wont find the leaky wire and repair the issue in this instance. So maybe a “Pseudo Safety Squint” would be a better fit here…

I’ve been nailed by so many ignition events in my day you would think I actually sought them out… I don’t…but I’m not afraid of them either. Separates the girls from the ladies quickly, I know that.

18-22 ft lbs is not very much, depending on your torque wrench, it’s very possible you didn’t even feel the click and went past it.

The right way to change plugs:
1: Remove plug wire from plug by turning and pulling wire off plug.
2: use compressed air to blow out any debri from around plug.
3: Loosen and turned out plug 1 - 2 revolutions and use compressed are to clear out around plug again.
3: Remove plug and inspect to compare with others. Set aside in order so you can do a side by side comparison. Cover openings with a rag so contaminants can’t fall into openings.
4: Always gap the plugs. Not enough time to explain, but necessary.
5: install plug to designated torque.
6: Put a small dab of dielectric grease in the end of the spark plug boot and attach it to plug until it clicks on to the plug. You may have marked the wires to avoid mixing them up.
7: Secure wires properly in their original routing and your done.

As far as the clicking goes, instead of self electricution, while it’s dark, use water in a mist sprayer and lightly spray a mist over wires until you see a spark. If it was me though I would just replace the wires with new. If the plugs were due, the wires are probably old to begin with. Just chaulk it up to regular maintenance. Then if clicking stops your good to go. If clicking continues, you can move to the next step of diagnostics.

Offhand, a plug could have been damaged during installation, a plug connector pulled loose, or in a few very rare cases the new plug may be bad. This can lead to a spark jumping down where you can’t see it.

For what it’s worth, I think using a torque wrench is a mistake as that can lead to thread problems. Best method with tapered seat plugs is snug and 1/8 of a turn and with gasketed plugs snug and 1/4 of a turn.
The thought ot torquing some plugs at 25 Ft.Lbs in an aluminum head makes me cringe a bit and I don’t know of any mechanics I’;ve ever worked with who used anything other than feel.

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