Possible LIMP Mode?

[Madskyline]

rb20det

so on a hot day a couple days back i was at a light idling and the car just started to sputter and shake, when i went to accelerate it had a weird popping noise from exhaust and loss of power some black smoke from exhaust and it just went away.
drove for a bit longer and problem came back this time it did not go away, i was close to home so took her easy, upon arrival i noticed smoke coming from engine bay, popped the hood and at the rear of the valve cover it was spitting out oil. i then noticed that the rear screws on the valve cover were starting to undo themselves(i could turn them by HAND!) so i tightened them and problem went away....for 2 days then it started again rechecked the screws and they were fine. any ideas boys?

[Madskyline]

just installed new valve cover gaskets. dint seem to do the trick, this usualy happens after the cars been driving for over an hour! help would be greatly appreciated.......also does anyone know how important the valve cover screw grommets are?

[Supraclean]

Does your car still have a stock cat? Type this problem into google man there are tons of threads on here regarding this.

My guess is you stock cat is pluged, if not there are a list of things you can check. Thoe valve cover gromets might be only part of your problem. They are important because it seals you valve covers on that keep oil in your head... also if its not sealing you gonig to have low oil pressure = bad.

[Skym]

Check the PCV valve. If blocked (needs to be cleaned) or faulty, could be overpressurising and creating the leak.

The grommets, half moons, gaskets should be replaced. Also liquid gasket applied to halfmoons before install and front, back of head on intake, exhaust side where gaskets go before installing cam covers on engine. If the grommets are crushed, screws can start to undo and leak in that area.

I think used Permaseal? camcover gasket kit (comes with grommets, half moons, gaskets) on my car. The Permaseal grommets look like a better design than factory. It hasn't leaked since using that kit.

[Madskyline]

so check PCV and shes still rattling....no leaks around the valve clover and it was fine for about a week and started again, i know about clogged cats but this problem is so once in a while it cant be a clogged cat, or evan a vacume leak? car runs great for a while starts bogging down then after letting engine temp cool problem goes away

[Madskyline]

if anyone has a scanner maby we could meet up.....THANKS guys!

[Skym]

Missing can be coilpack leaking charge or airleak near MAF (stutter, similar to coilpack problem and is usually the intake hose clamp on MAF or crack inbetween ribs on rubber intake pipe behind MAF).

The missing with coilpacks is the engine running on 5 cylinders intermittently, then starts running on 5 cylinders permantly when coilpack is leaking alot. Grey tracking marks on both sides of coilpacks under mounting bracket is a sign of them them leaking charge. Coilpacks should be replaced every 100,000km and cause of coilpack failure is using incorrect sparkplug gap when upping boost level, incorrect heatrange or just age. Coilpack loom is another cause of missing (should be replaced as part of routine maintenance). Same with injector loom.

[Madskyline]

iv done some reading and get mixed anwsers whats the proper gapping for 10-12lb boost?

[Skym]

Factory gap is 1.1mm and use a NGK PFR6A -11 (-11=1.1mm gap) plug gapped down to 0.8mm for intake, exhaust, BOV which should produce around 250hp (engine) at around 12psi, up from factory 215hp. Some gap sparkplugs to 0.8mm or less due too weaker coilpacks.

Factory sparkplug for RB20DET is NGK PFR5A -11.

[Madskyline]

ok so new maf dint do the trick and the boot behing it seemed to have no cracks, all coilpacks look fine and no grey markings would make me feel that there not the problem. the loom seems to look in good working order......anything else? at a stand still here guys....thanks for the help so far!

[Skym]

this usualy happens after the cars been driving for over an hour!

If drive car for long distance, headgasket can start to leak. Do a compression test, pressure test via radiator pressure test kit. The leaking via camcover gasket could be a symptom of pressure from cylinder or cylinders getting into oil system and pressure finding a way to escape via the weakest point (where it leaks).

The rich problem could be ECU reacting to the unstable combustion due to leak (thinks engine is knocking).

[Madskyline]

ok so the problem is more consistant now, but it will come and go every few minutes to sometimes a few seconds apart.....she will bog then go back to normal then bog again thanks for all the help still!

[DarkCaporaL]

Did you test your coilpacks with a multimeter?

[Madskyline]

could you please give me a rundown on how to test coilpacks with a multimeter and what readings i should be looking for, THANKS!

[DarkCaporaL]

It's in the manual in my signature, but the rundown is:

- Take out coil pack
- Place it so that the pins are facing towards you
- Mesure Ohm resistance between the left and middle pins (I believe it's + and E?, just make sure it's left and middle)
- Resistance should be between 0.6-0.9 Ohms.