Reading Spark Plugs
04-03-2011, 11:27 AM
#1
Reading Spark Plugs
So my 22re has an intermittent pre-ignition problem. It seems to happen on the highway, 2000-3000 rpm, at moderate throttle position. When it happens it will stop if I floor it.
The engine has about 40k on a rebuild, 268 cam, fuel injectors have been serviced. It has plenty of power, gets decent mileage, and passes emissions. The EGR and PAIR system was recently removed. O2 sensor is also pretty new. Timing is set at 5* and the valve lash is set at IN/EX 7/9 thou. as per Engnbldr's recommendation.
Here are some pics of my spark plugs with 5k miles on them. They are the factory spec Denso's. Can one of you gurus take a look and see if they tell you anything about my pinging problem?
Only three because I dropped the 4th and messed it up
Closeup of #3
Closeup of #1
The engine has about 40k on a rebuild, 268 cam, fuel injectors have been serviced. It has plenty of power, gets decent mileage, and passes emissions. The EGR and PAIR system was recently removed. O2 sensor is also pretty new. Timing is set at 5* and the valve lash is set at IN/EX 7/9 thou. as per Engnbldr's recommendation.
Here are some pics of my spark plugs with 5k miles on them. They are the factory spec Denso's. Can one of you gurus take a look and see if they tell you anything about my pinging problem?
Only three because I dropped the 4th and messed it up
Closeup of #3
Closeup of #1
04-03-2011, 02:02 PM
#4
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Those look ok to me. If the timing is adjustable on your engine, you might try retarding it a degree or so. Also, you mentioned a rebuild... If they took a few thousanths off the deck of the head, you might have a slightly higher compression ratio, and hence the slight ping. My 94 had had the head off twice and exhibits very similar simptoms. It has been like that ever since the first valve/timing chain job at 155K. I wouldn't worry about it.
You also might try a tank or two of higher octane gas, or dump some octane booster in and see if it helps.
Frankly, the gas these days is crap compared to that which was available 15 years ago.
Another option is to drop it down a gear and see if the issue goes away. That's what I do on my Moto Guzzi.
Ciao,
Kip
You also might try a tank or two of higher octane gas, or dump some octane booster in and see if it helps.
Frankly, the gas these days is crap compared to that which was available 15 years ago.
Another option is to drop it down a gear and see if the issue goes away. That's what I do on my Moto Guzzi.
Ciao,
Kip
04-03-2011, 04:09 PM
#5
Registered User
The tan flaky stuff on the plugs is probably calcium/magnesium from the oil, and it looks like some oil deposits on the base of the plug. Probably your rings are passing some oil. Also looks like it's running a bit lean.
Here are some spark plug reading sites:
http://www.densoiridium.com/howtoreadusedplugs.php
http://www.tuner-junction.com/TJForu...ark-plugs.html
http://www.autohausaz.com/html/spark...lug-wires.html
http://www.northursalia.com/techdocs/spark/spark.html
http://aboutkarting.com/plugs/
http://roadstarclinic.com/content/view/70/127/
http://www.theultralightplace.com/sparkplugs.htm
The pinging is probably from a combination of lean mixture, high combustion temps due to the lack of EGR, and probably some of those flaky deposits get red hot, serving like a glow plug and igniting mixture early. When you floor it, the computer goes off closed loop and the open loop mixture settings are richer so that may be enough to cool things down and stop the pinging.
Probably if you replaced the EGR, that alone may stop the pinging. It only operates at part throttle cruise, not at full throttle, so it doesn't cost you any power. Improves gas mileage a teeny bit. Running without EGR makes it run hotter, which puts a lot more stress on exhaust valves and head gasket (plus increases the pinging).
You also can look into the lean running, though I think these computers tend to normally run things on the lean side. Make sure there are no air leaks between air meter and throttle body, and no vac leaks elsewhere. Run a bottle of Red Line SI-1 Complete Fuel System Cleaner through to clean the injectors and get them as balanced as possible (short of sending them to Witchhunter). Looks like the injectors are not very imbalanced, tho. You might look into adjusting the air meter to run it a bit more rich.
You can clean some of that flaky stuff off the pistons, valves & head by running a gallon of water through. See:
https://www.yotatech.com/forums/f116...l#post51124041
Put a new set of plugs in.
You might try running a 180 deg stat (rather than the stock 190 deg one) - that's the t-stat for an 85-88 22RTEC, part # 90916-03083. It might cut down on the pinging, and anyway it would be a good idea since you removed the EGR.
Let us know how you make out.
Here are some spark plug reading sites:
http://www.densoiridium.com/howtoreadusedplugs.php
http://www.tuner-junction.com/TJForu...ark-plugs.html
http://www.autohausaz.com/html/spark...lug-wires.html
http://www.northursalia.com/techdocs/spark/spark.html
http://aboutkarting.com/plugs/
http://roadstarclinic.com/content/view/70/127/
http://www.theultralightplace.com/sparkplugs.htm
The pinging is probably from a combination of lean mixture, high combustion temps due to the lack of EGR, and probably some of those flaky deposits get red hot, serving like a glow plug and igniting mixture early. When you floor it, the computer goes off closed loop and the open loop mixture settings are richer so that may be enough to cool things down and stop the pinging.
Probably if you replaced the EGR, that alone may stop the pinging. It only operates at part throttle cruise, not at full throttle, so it doesn't cost you any power. Improves gas mileage a teeny bit. Running without EGR makes it run hotter, which puts a lot more stress on exhaust valves and head gasket (plus increases the pinging).
You also can look into the lean running, though I think these computers tend to normally run things on the lean side. Make sure there are no air leaks between air meter and throttle body, and no vac leaks elsewhere. Run a bottle of Red Line SI-1 Complete Fuel System Cleaner through to clean the injectors and get them as balanced as possible (short of sending them to Witchhunter). Looks like the injectors are not very imbalanced, tho. You might look into adjusting the air meter to run it a bit more rich.
You can clean some of that flaky stuff off the pistons, valves & head by running a gallon of water through. See:
https://www.yotatech.com/forums/f116...l#post51124041
Put a new set of plugs in.
You might try running a 180 deg stat (rather than the stock 190 deg one) - that's the t-stat for an 85-88 22RTEC, part # 90916-03083. It might cut down on the pinging, and anyway it would be a good idea since you removed the EGR.
Let us know how you make out.
04-03-2011, 06:31 PM
#6
sbwalker, thanks for the tips!
I didn't realize that about the EGR... thought it was bad news most of the time. I'll look into getting it functional and back in place. I'll also look into running a colder plug. Gonna try a little octane boost too...
I ran some Amsoil cleaner through it very recently. Also, the injectors were actually done by Witchhunter at the rebuild, 40k ago.
I didn't realize that about the EGR... thought it was bad news most of the time. I'll look into getting it functional and back in place. I'll also look into running a colder plug. Gonna try a little octane boost too...
I ran some Amsoil cleaner through it very recently. Also, the injectors were actually done by Witchhunter at the rebuild, 40k ago.
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