Poor MPG + Misfire

[Llia]

PLUG DRIVERSIDE
Is this considered lean?

VALVE COVER, COIL PACK REMOVED

PCV PORT INTAKE MANIFOLD
This was very dirty

PCV HOSE INTAKE MANIFOLD
This was also very dirty

THROTTLE BODY

I did see the orange thing inside the manifold looking down through the hole but it was really dirty.
Getting 30-32 MPG sometimes worse.
Every so often the problem seems to go away. Very bad in the mornings on startup though.
Can a catch can help any? Would I benefit from the bypass mod?
Do I need a new intake manifold or valve cover?

- Thanks

Oh and that plug on top of the manifold had an o-ring and a plastic bit. But I wasn't sure if I put it together right when I reattached them. They fell on the ground when I pulled the connection.

 

[Llia]

Only 62 degrees out and the car is smoking a lot more than usual. White. Some aroma but nothing glaringly coolanty.

There sounds like a slight hiss at the back of the intake manifold or thereabouts. I only had WD4o and sprayed that but no change in revs. Might go out and get some carb cleaner if that is easier to find the hiss. Then again if the hiss is air forced out, it wouldn't ingest the spray. hmm.

 

[bluejay]

Your hiss could be an air leak causing more air to come in which would make your car wanna dump in a bunch more fuel. Do you have any cel's or does the car feel more powerful at (wot)? Usually when u mess with a stock intake these types of things can happen . But could be solved with something as simple as some kind of air straightener. You can drive ur car while running lean but you don't want do it for too long cause then u start messing up more expensive stuff like the cat's

 

[Llia]

No CELs. And the intake is back to stock. it only a minor nick in the intake tube where I epoxied the parts together, but I sanded that smooth.

I'll keep an eye on CAT temps, what would be considered too hot?

I'm using Torque Pro to see how things are running.

 

[Llia]

Alright here was my CAT temps with some night driving, almost 1500 F. Doesn't seem too bad. It was between 800 F - 1600 F that I read was normal
Oil temp was in the normal 230 250 Range
Coolant never went above 228 F.
Misfire only happen under vacuum or right after. Car ran pretty well this time around. Probably because it didn't sit all night before I drove it.


Much cleaner arrangement. I found my phone can't keep up if I add any more gauges.

 

[JesusTheAgnostic]

I'm not sure if I remember but when I datalog and go over it, I don't think the temperature, whichever it's reading goes past 210. Though I don't really remember. What kind of tires do you have? Do you go WOT a lot? I've never pulled the plugs out, but the rest of the stuff on yours looks the same as mine. I have concluded that there is oil all over the intake. Why? Idk. I guess the engineers thought it would be a good idea. I remember reading about half of the bypass thread and I think they said it did reduce the amount of oil present. How do you know you're misfiring? Because according to the logs my car misfires like crazy, but I hear that when you misfire the check engine light flashes on this car. Is it anything like what I described in my no boost thread?

 

[mja]

Spark plugs look alright. To read them, make a hard run or two and shut off ignition and coast/stop. Pull them directly after that and the ceramic will take a 'snapshot' if you will of the cylinder environment at WOT.

This is the best article I found from the oldskool way:
Spark Plug Reading 101 by Mike Canter - Dragstuff

If the issues happen cold, gota pinpoint things which control the idle circuit. If it happens under the vacuum to boost switch, and youve got oil in the intake/throttle body, PCV may be a problem.

No one has posted yet how to check the health of the orange check valve or cam cover vacuum diaphragm, so you'd be doing trial and error replacing those parts. I'd replace em at once in case the other was bad and causes the new replaced part to be defective. AFIIK you're treading new water to pinpoint this common issue without the dealer replacing parts. Stakes are higher when its coming from your wallet... are you still under warranty?

I'd eliminate misfire from spark/coil pack by checking the resistance of the coil pack. Gap the plugs and let us know what else you find.

 

[JesusTheAgnostic]

Another thing, if you're smoking white that's bad, very bad. Blue means you're burning oil, black means you're running rich, and white means you've got a serious problem. Are you sure it's not a blue smoke?

 

[mja]

This same/similar problem happened with mine when the turbo blew. Lots of smoke on startup and under low vac/boost crossover

 

[HotBoxer]

Looks like you need an oil catch can for your PCV! Check out that oil catch can thread.

 

[Llia]

This same/similar problem happened with mine when the turbo blew. Lots of smoke on startup and under low vac/boost crossover

...are you still under warranty?

I'd eliminate misfire from spark/coil pack by checking the resistance of the coil pack. Gap the plugs and let us know what else you find.

Nope, not under warranty.

Not sure if I can gap my irridium plugs?

I have a multi-meter FLUKE 115 but I'm not that confident using it. I took electronics ages ago but really forgot a lot.

There are multiple pins on the connection. Is there a how to on testing it?


I did have a loss of power trying to overtake someone on the freeway. It was like it refused to acknowledge I pushed the pedal.

 

[Llia]

How do you know you're misfiring? Because according to the logs my car misfires like crazy, but I hear that when you misfire the check engine light flashes on this car. Is it anything like what I described in my no boost thread?

The Torque Pro shows the number of misfires. Usually 2 in Cylinder #4, as seen in my first screen shot of the app.

I don't see the check engine light flash, yet.

 

[mja]

Yes you can gap the plugs.

The cam cover diaphragm leaks oil into the #4 boot and condenses moisture when it heats up. Check the spring inside the coil pack boots at #4 & #3 for corrosion, my guess is they'll look crummy. Was the diaphragm/burst disk busted or was it replaced?

There are plenty of youtube videos and writeups on how to check coil packs on the net. I've always used Ohm resistance setting on the multimeter and compared this to a stock part. The guys at the part store should work with you here to test resistsnce vs a stock coil pack, if not find another part store.

This would be easier if someone had the electrical manuals, can you still buy these things?

 

[JesusTheAgnostic]

The Torque Pro shows the number of misfires. Usually 2 in Cylinder #4, as seen in my first screen shot of the app.

I don't see the check engine light flash, yet.

The data log I was looking at for mine says I misfire up to 16 times per cylinder. Though it says max, which I'm assuming it's not total, so I don't know exactly how I'm supposed to read that.

 

[JesusTheAgnostic]

I did have a loss of power trying to overtake someone on the freeway. It was like it refused to acknowledge I pushed the pedal.

What gear where you in? Do you feel like it just dumped boost and didn't want to build it back up?

 

[Llia]

What gear where you in? Do you feel like it just dumped boost and didn't want to build it back up?

It was auto. It might have been that it was refusing to downshift, so I was stuck trying to accelerate in too high a gear.


Small update:
I wont have time to take things apart till Friday so the coil pack test is on hold. Today as I ran low on gas again, the car started to misfire 4-6 times in all cylinders.

Should I attempt a fuel cleaner?


Vacuum @ idle sometimes likes to be around -10hg, but runs best around -16.5hg

 

[mja]

I think if you keep driving this thing daily until you can fix it, something bad's guna happen.

 

[Llia]

I think if you keep driving this thing daily until you can fix it, something bad's guna happen.

I know,

Went to the parts store to look for the compression checker, and some other things.

 

[mja]

Check your cylinders* out and make sure pressure is alright. If the cylinders are still good, unfortunately you'll need to check the health of these parts:

#1 Intake manifold - pull it and see if the orange check valve lives. If not, buy a brand new intake stat and install. Ebay they're going for 250-300$

Coil pack, plugs (maybe), cam cover if leaking or if suspected to be blown, check the condition of the PCV outlet in the intake, if all these have been checked and/or replaced and you're still blowing smoke, may be turbo time

Also check all gaskets on motor for signs of leakage. Good luck.

 

[JesusTheAgnostic]

You can check the orange valve from inside that port you showed in the picture at the beginning. Just stick your phone camera with flash there and snap a few, you should be able to see if it's there.