Rb26det Misfire And Low Oil Pressure

[AE86 Spoontah]

Hey guys, only just recently i have had trouble with my engine misfiring bad. Its an R33 26 with big single in an R32 GTS-T, WOLF 3d, near brand new plugs gapped to .7, stock coils. It has never happened before until it was about 30deg the other night and usually after about 15mins of normal driving it starts.

I was driving along at about 4000 rpm in second and it started sounding like your typical boxer engine, and assumed an injector plug had come off as it's done it to me before. Checked all plugs and the problem stopped . . . maybe not. Started the car up, sounded good, drove along and it came back then disappeared, came back, disappeared etc. it even happens on idle sometimes (it's an extremely rapid misfire sounding like a machine gun haha)

Doesn't matter what gear or what rpm but gets really bad when you load the engine up or stay on constant throttle, and if you hit boost it will go away sometimes. The stock oil pressure gauge in the dash will get close to zero then jump to about 4, then just fall and rise as it pleases. Engine doesn't blow smoke and no oil in turbo inlet or exhaust.

I have checked all plugs and had to change number one as it looked fried (less than 2000km old).The rest still look new

Cut out each injector while car was running to see if there was no change on one. all good though

Changed fuel filter over in case it was blocked

I'm guessing i should just seal my coils with silicone and do a comp test but while i'm there should i be looking at anything else.

Any help appreciated

Edited January 21, 2010 by AE86 Spoontah

[Sheriff Wan]

Sounds like could be coils... i'd be leaning more towards o2 sensors or AFM's

Given it only happens after a while of driving im leaning towards o2's...

have you checked those?

[AE86 Spoontah]

No i havent and there is no AFM. . .

but i have a theory after drivng home today. Another hot day and after 10 mins it started happening. Checked all injector plugs again an no change to engine noise to it's got to be the coil packs. Reason i'm thinking this is that there are hairline cracks in the coils and when under bonnet temps get too hot, the cracks expand and the spark jumps out. I'm sealing them up now so i'll see if that fixes the problem.

[R.3.2.G.T.R]

double that coil plugs "click" when you attach it as it's happened before where loose connection causes intermittent misfiring

[AE86 Spoontah]

double check that coil plugs "click" when you attach it as it's happened before where loose connection causes intermittent misfiring

They all click apart from no.1 but you can't pull no.1 plug off unless you release it how you normally would

Edited January 22, 2010 by AE86 Spoontah

[AE86 Spoontah]

Sealed up coils with some quick cure high temp sealant but hasn't fixed the problem. It's gotta be electrical is it "pops" alot more now and the pops are louder like there is bulk fuel being ignited.

Could there be a problem with my ignitor?

[AE86 Spoontah]

Also went to check my O2 sensor but there isn't one, WTF?

[260tech]

Sealed up coils with some quick cure high temp sealant but hasn't fixed the problem. It's gotta be electrical is it "pops" alot more now and the pops are louder like there is bulk fuel being ignited.

Could there be a problem with my ignitor?

Hi there, dunno what your problem is but seems like there are two which could be related. If you have sealed up your cracked coilpacks & the sealant has had sufficient time to completely cure without fixing problem or as you say making it worse I would be borrowing some known good coilpacks to substitute & check. Also I'm told that the factory Nissan oil pressure senders/gauges on Skylines are notoriously dodgy but you could also have bad electrical earthing causing your combined problem.

My 2c

Cheers GW

[AE86 Spoontah]

Hi there, dunno what your problem is but seems like there are two which could be related. If you have sealed up your cracked coilpacks & the sealant has had sufficient time to completely cure without fixing problem or as you say making it worse I would be borrowing some known good coilpacks to substitute & check. Also I'm told that the factory Nissan oil pressure senders/gauges on Skylines are notoriously dodgy but you could also have bad electrical earthing causing your combined problem.

My 2c

Cheers GW

I might have to borrow my mates Splitfires and see if that helps. I heard to that the factory gauges shit at the best of times

too.

[AE86 Spoontah]

Put mates Splitfire's in and worked for about 10mins and the problem came back again so it's not the coils. Put my standard coils back in, sprayed coil pack module with contact cleaner and kept the vally cover off this time and the problem didn't come back after 10 mins, so i gave it a boot and it did it abit on boost. Maybe the coil pack module is getting too hot? Any one got a CPM i can borrow in Perth to test for 5 mins? Cheers

Edited January 23, 2010 by AE86 Spoontah

[AE86 Spoontah]

Found that the problem was the ignitor was getting too much heat soak in the hot weather so i relocated it next to the brake booster and have no problems with misfiring even on a 40 degree day. Crisis averted haha