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lourens13
06-11-2012, 07:31 AM
The motor looking for some help with is a blacktop s13 sr20.

At the event yesterday had some problems with the motor misfiring when hot, after doing consecutive runs with less time to cool down.

Checked the plugs, looked good, changed them anyways, still happened. Checked the wideband under boost, was around 12, so maybe a little rich. Either way, what could cause it to miss only when its hot?
mfsnh
06-11-2012, 08:37 AM
When the temp under the hood goes up the resistance in the plug wires goes up which would make the spark have a harder time to get to the plug. Try either replacing the plug wires or buy some shielding for them would be my guess

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blksylv
06-11-2012, 08:54 AM
Check coilpacks and coolant temp sensor. Sr's don't have plug wires
mfsnh
06-11-2012, 08:57 AM
Shit duh sorry I was thinking my car lol

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JDMRIDDAZ
06-11-2012, 02:43 PM
Check resistance on coils...1k ohm
there good...
But if there good u need to check w a spark light
coil can check out per to fsm
but can still give a weak spark..=misfire
fliprayzin240sx
06-11-2012, 05:48 PM
What spark plugs and what gap?
lourens13
06-11-2012, 05:59 PM
NGK BKR7's gapped to 32.
budlite
06-11-2012, 06:02 PM
no info on motor

but either coils or wires are ur issue
fliprayzin240sx
06-11-2012, 06:05 PM
NGK BKR7's gapped to 32.

Gap it down to 28 (doubt it would make a lot of difference), double check the timing. Personally, I like BCPR7s, cheaper plugs and can change it every other oil change.
lourens13
06-11-2012, 07:03 PM
no info on motor

but either coils or wires are ur issue

SR20DET blacktop, top mount TD06, BC stage 2 cams, stock bottom end. 300ish whp.
GARzNSANE
06-12-2012, 06:35 PM
Misfiring = stutter around 2-3k RPM? Does that problem exist through the entire powerband?
jdm538
06-12-2012, 06:42 PM
"when hot," it sounds like a coilpack or ignitor problem.
steve shadows
06-12-2012, 11:04 PM
Well could be a few things.

Always want to check your plugs, your ignitor coils or coil packs and also check the ignitor chip. There is also a wire that goes right to the back of the head that is the grounding wire for the coil pack harness. Make sure this has a good contact on the firewall and I would also connect it to the back of the head. A lot of times these come loose after a spa is done or they forgot to wire the ground in the first place.

Also want to check your CAS wiring as well. I have noticed a lot of these being frayed or being loose in the plug as well causing other issues with the ignition miss firing.