Spark plug.. You be the judge
- Thread starter MAK507
- Start date
I had one come out like that recently, but it was #5.
Car is running much smoother now. I have verified spark to that plug & I will be pulling the new plug for a re-check after some drive time.
Interesting that your compression test readings were highest at #4. Maybe some oil is leaking into that cylinder?
Car is running much smoother now. I have verified spark to that plug & I will be pulling the new plug for a re-check after some drive time.
Interesting that your compression test readings were highest at #4. Maybe some oil is leaking into that cylinder?
No disintegrations
Well-Known Member
- Joined
- Dec 27, 2015
notice how #4 has the highest compression? It looks to be burning a lot of oil. The layer of carbon on the piston may be raising the number. Can you take picks looking down into the plugs?
- Joined
- May 28, 2001
Valve guide? seal?
Miles on engine?
Miles on engine?
Take pics with plugs out?
Motor has less than 200 miles
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No disintegrations
Well-Known Member
- Joined
- Dec 27, 2015
Take picks of plugs looking down in the ceramic part.
John Larkin
Sublime Master of Turbology
- Joined
- May 25, 2001
I too think it is a spark issue, a misfire. Check that plug's wire for comparable resistance to the other ones.
Thank you guys, I'll check this out tomorrow.
Coil pack and ignition control module was recently purchased from Kirban Performance. They say the cpack is ACDelco. Hopefully this is an easy fix. How can I diagnose the comments regarding the oil in the cylinder? My buddy thinks it's the ecm that caused this...? (My ignition module had melted if some of you recall my past post-- and he thinks whatever happened there could've shorted the ecm and could be causing my issue)
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Coil pack and ignition control module was recently purchased from Kirban Performance. They say the cpack is ACDelco. Hopefully this is an easy fix. How can I diagnose the comments regarding the oil in the cylinder? My buddy thinks it's the ecm that caused this...? (My ignition module had melted if some of you recall my past post-- and he thinks whatever happened there could've shorted the ecm and could be causing my issue)
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its not likely the ECM, the only cylinder specific thing the ECM can control is the injectors. You can swap the injector plugs between 2 cylinders to see if the problem moves, or perhaps have the injectors flowed. (this presumes the plug is fuel-fouled, not oil)
Bob
Bob
- Joined
- May 28, 2001
Bob mentioned fuel fouling.. Another look at that plugs gives me an indication it may be fuel foul.
The "fluffy" bits of material may be fuel...
Also, the threads on the plugs look to be really wet..What are you using on them, for lube?
The "fluffy" bits of material may be fuel...
Also, the threads on the plugs look to be really wet..What are you using on them, for lube?
They were installed with nickel anti seize.
A shop told me they can flow my injectors... I'm just thinking about buying new ones if yall think it's injector related.
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- Joined
- May 28, 2001
What's in there, now?
Were they new/fresh, when the engine was built?
What condition is the inj harness, and connectors in?
Bottom line... No way to really read those plugs, other than there's "sumptin wong".
Install a fresh set, make a couple hard pulls, read them. Idle time, driving around, isn't going to tell much.
What about data logs?
If you have an ohm meter, you might want to check the resistance of that plug in comparison to the rest. I had that happen to my airplane engine. If no ohm meter, maybe clean the bad plug and put it in another cylinder and see if the same thing happens.
Even if the plugs are new, sometimes you can get a bad one. Just a thought ...
Even if the plugs are new, sometimes you can get a bad one. Just a thought ...
- Joined
- Feb 18, 2006
Takes 15-20 minutes to switch the injector with another. That will give a direction to go in.
Update: I've gone ahead and bought new Siemens 60lb fuel injectors (flow matched) from Eric at TurboTweak. I also bought the power logger so that I can provide data logs. Bought a new ECM as well. I'll let you guys know when I get everything.
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You'll be calling this car a ''money pit' before long. Shotgunning parts without troubleshooting the actual problem can sometimes bit you in the ass.
lLick that fouled plug... does it taste like gas or oil? If it's oil, the injectors aren't going to solve it. If it was a coil pack/ign module issue you'd have two plugs (from the same section) having issues.
On your compression numbers that's not a guaranteed way to rule out a cylinder leak like a head gasket. A leak down test is much more accurate (and can still give a false positive with these engines)
lLick that fouled plug... does it taste like gas or oil? If it's oil, the injectors aren't going to solve it. If it was a coil pack/ign module issue you'd have two plugs (from the same section) having issues.
On your compression numbers that's not a guaranteed way to rule out a cylinder leak like a head gasket. A leak down test is much more accurate (and can still give a false positive with these engines)
