Glazed spark plug? Bad Idle
03-17-17, 08:46 PM
#1
Junior Member
Thread Starter
Glazed spark plug? Bad Idle
So I am (hopefully) int he process of restoring my FD to life. It sat for about 18mo. (I know, shame on me!) Unfortunately I came across Aaroncake.net a little too late to store it correctly (Whoops).
It starts and runs but has the following symptoms:
- Sometimes dies randomly while warming up and after warming up.
- Requires a little throttle to start up after dying but not when first starting.
- AFR gauge on my turbo timer is constantly reading 20(!) with 02 sensor reading ~0.01.
- Sometimes dies if throttle is depressed more than a small amount.
- Very poor throttle response.
- Dies after throttle is released as rpms fall right past idle speed to 0.
- Doesn't seem to smell as much like fuel in the exhaust as I seem to recall in the past.
- Pinging noise from engine/exhaust manifold. Basically continuous during idle. Sometimes idle is rough and pinging is perhaps a little worse.
My car/mods:
- ~53k miles on car/transmission
- Reman engine installed in 2005 ~5k miles since then
- 2mm apex seals
- Street Port(Stage 2?)
- Power FC (Unfortunately I don't have a commander or datalogit)
- Stock Ignition Coils
- T78
- Greddy FMIC
- Walbro 255 fuel pump
- IIRC Stock Secondaries being used as Primaries w/ 1200cc secondaries
- 3" downpipe, straight midpipe, Ti race exhaust
From my research I first thought I had an issue with the TPS and also possibly with the IAC/ICV. I am working on ruling out either of those using excellent form posts about both. After reading some forum posts about spark plugs and fouling (same plugs since engine installation), I decided to pull my plugs and inspect for fouling. The first sat for the front rotor was about what I expected based on my reading. The other was pretty horrifying. WARNING graphics images!
From left to right they are:
Front Rotor Trailing BUR9EQP
Front Rotor Leading BUR7EQP
Rear Rotor Trailing BUR9EQP
Rear Rotor Leading BUR7EQP
Both front rotor plugs have a decent amount of dry black carbon on them.
The rear trailing has an obvious wet oil look with similar carbon buildup to front plugs
The rear leading was bone dry and appeared to have some kind of glazing that bridged the gap between the electrode and the ground straps. IT is pretty gunked up with this glaze like material.
Questions:
What is the glazing material?
Is it likely all over the inside of my rotor?
Is it likely to have damaged my rotors or seals?
Does the oil on the rear trailing plug indicate an oil seal failure or is it normal for a fouled plug?
Is the pinging I am hearing detonation/pre-ignition? How best to verify proper operation of my fuel injectors?
If I am misfiring on the rear rotor, could burning fuel in the exhaust cause the pinging I am hearing?
If fuel is not burning until it reaches the exhaust would it cause the O2 sensor to read extremely lean?
After replacing the plugs (9's all around based on what I have read in the forums) and verifying proper operation of the TPS and IAC, what would you experts out there recommend I do to troubleshoot issues without potentially damaging the engine further?
Thanks for reading if you made it this far. I tried to include all pertinent details. I'm sure I left some stuff out (Including some more questions
)
It starts and runs but has the following symptoms:
- Sometimes dies randomly while warming up and after warming up.
- Requires a little throttle to start up after dying but not when first starting.
- AFR gauge on my turbo timer is constantly reading 20(!) with 02 sensor reading ~0.01.
- Sometimes dies if throttle is depressed more than a small amount.
- Very poor throttle response.
- Dies after throttle is released as rpms fall right past idle speed to 0.
- Doesn't seem to smell as much like fuel in the exhaust as I seem to recall in the past.
- Pinging noise from engine/exhaust manifold. Basically continuous during idle. Sometimes idle is rough and pinging is perhaps a little worse.
My car/mods:
- ~53k miles on car/transmission
- Reman engine installed in 2005 ~5k miles since then
- 2mm apex seals
- Street Port(Stage 2?)
- Power FC (Unfortunately I don't have a commander or datalogit)
- Stock Ignition Coils
- T78
- Greddy FMIC
- Walbro 255 fuel pump
- IIRC Stock Secondaries being used as Primaries w/ 1200cc secondaries
- 3" downpipe, straight midpipe, Ti race exhaust
From my research I first thought I had an issue with the TPS and also possibly with the IAC/ICV. I am working on ruling out either of those using excellent form posts about both. After reading some forum posts about spark plugs and fouling (same plugs since engine installation), I decided to pull my plugs and inspect for fouling. The first sat for the front rotor was about what I expected based on my reading. The other was pretty horrifying. WARNING graphics images!
From left to right they are:
Front Rotor Trailing BUR9EQP
Front Rotor Leading BUR7EQP
Rear Rotor Trailing BUR9EQP
Rear Rotor Leading BUR7EQP
Both front rotor plugs have a decent amount of dry black carbon on them.
The rear trailing has an obvious wet oil look with similar carbon buildup to front plugs
The rear leading was bone dry and appeared to have some kind of glazing that bridged the gap between the electrode and the ground straps. IT is pretty gunked up with this glaze like material.
Questions:
What is the glazing material?
Is it likely all over the inside of my rotor?
Is it likely to have damaged my rotors or seals?
Does the oil on the rear trailing plug indicate an oil seal failure or is it normal for a fouled plug?
Is the pinging I am hearing detonation/pre-ignition? How best to verify proper operation of my fuel injectors?
If I am misfiring on the rear rotor, could burning fuel in the exhaust cause the pinging I am hearing?
If fuel is not burning until it reaches the exhaust would it cause the O2 sensor to read extremely lean?
After replacing the plugs (9's all around based on what I have read in the forums) and verifying proper operation of the TPS and IAC, what would you experts out there recommend I do to troubleshoot issues without potentially damaging the engine further?
Thanks for reading if you made it this far. I tried to include all pertinent details. I'm sure I left some stuff out (Including some more questions
)
