SR20DET. Inputs and experience needed.

[Banana_Cute]

Ok. Scenario.
SR20DET

Car would Idle fine. Would smoke when I rev it high.
#4 cylinder fouling the plugs
I unplug my injector AND coilpack(havent tested it yet) but the idle stayed the same. No change in engine idle or sound.
I unplug the others and you can tell the change.
I opened the oil filler and I notice blow by smoke more than usual. And a little bit of white residue under the cap.
Engine temp is steady, I've even driven the car to work a few times but just a bit smoky, sometimes more than usual.

I'm leaning towards a blown headgasket, very minimal( I guess) but I'm stumped on why the idle did not change when I unplug both injector and coilpack on #4 cylinder.

I unplug the MAF and car shuts off almost instantly.

I havent tried doing a leak down and compression test yet though. Any inputs and I'll update this thread when I do so.

I just want to buy what I need and send it in for a rebuild hoping for no other surprises.

[ultimateirving]

Leaky valve seals maybe? possible it killed the number 4 spark plug? sounds like something is not firing in that cylinder. Whats the plug look like?

[cotbu]

Pulling spark or fuel from cylinders narrows down what cylinder isn't firing. By NOT making a change in the idle, you found the cylinder.

NOW, you have to determine whether it is spark or fuel or both. Take out the coil pack, put in the sparkplug, then ground it, spin engine over or spin cas. Look for spark.

Fuel injector, remove the rail, place a rag, cardboard under the injectors, spin engine over or cas. Look for wet spots under each injector.

Use common sense and caution.

My guess fuel contamination, or water or oil.
Fuel and water will leave the residue under the cap, but so will contaminated oil. So probably head gasket.
The oil contaminate, would usually burn off at operating temperature. So yeah head gasket if it doesn't.

Sent from a Highly Boosted Note 4.5!!!

[Banana_Cute]

I forgot to mention. Yes I did pull the spark plug and it is wet.

So for anyone who has gotten or done a complete rebuild, what am I looking at? Cost wise? Hopefully I can get away with it and not have a crack sleeve..

I should'nt have installed that bullshit MBC from Ebay.. the only thing janky mechanical I've used.. FML.

[kaoliu]

Have you tried swapping the coil from another cylinder to #4 to see if it'll still result in a wet plug?

[tynommepe]

Take out the coil pack, put in the sparkplug, then ground it, spin engine over or spin cas. Look for spark.http://goo.gl/tVxTl6

[Banana_Cute]

So I was able to get a compression test and it goes like this

#1 = 90
#2 = 90
#3 = 90
#4 = 30

This is test after warm up, TB wide open, and also the #4 cylinder, I also used oil but compression didnt change, which indicates good rings, I have yet to do a leak down test. The spark plug also indicates overheating as well...Anyways. Thanks everyone.

[coupesallday!]

Just rebuild the motor. Those are low numbers.

[cotbu]

So I was able to get a compression test and it goes like this

#1 = 90
#2 = 90
#3 = 90
#4 = 30

This is test after warm up, TB wide open, and also the #4 cylinder, I also used oil but compression didnt change, which indicates good rings, I have yet to do a leak down test. The spark plug also indicates overheating as well...Anyways. Thanks everyone.

That doesn't mean good rings!

Sent from a Highly Tuned Note 4.5!!!

[Kingtal0n]

you might have used a bad compression tester. Although if you are correlating a misfire on cylinder number 4 with an odd ball low number, even from a bad tester, there is a higher chance that something on cylinder #4 needs attention.

[AzS13hatch]

From those numbers, it looks like you need to tend to the entire bottom end, not just #4. If it is the head gasket making 4 so low, that could be a temporary fix, but I would at a minimum re-ring all cylinders after checking to ensure the cylinder walls are within specs. Of course, if you do a head gasket, make sure to get the head resurfaced to ensure its flat and not warped.

[Banana_Cute]

That doesn't mean good rings!

Sent from a Highly Tuned Note 4.5!!!

It could be a bad tester but from what I've read using a teaspoon of oil and doing a compression test, if the compression does not change, the rings arent damage..

So I'm looking at a complete rebuild on this then huh.... ugh.

[Kingtal0n]

It could be a bad tester but from what I've read using a teaspoon of oil and doing a compression test, if the compression does not change, the rings arent damage..

So I'm looking at a complete rebuild on this then huh.... ugh.


you need to perform another compression test. Use a known good tester, on a known good engine. THEN test your engine. make sure you crank with a good battery, throttle wide open. No oil and WITH oil, 2 tests back to back, 8 different numbers.

THEN and ONLY THEN can you know the next step. Do not take shit apart until you do this.

[fullthrottle]

He probably rented the compression tester from autozone. Those things are so used that Ive always gotten 90psi on good cylinders. I used a snapon compression tester and got 165 psi lol. Id just look for consistency. So your #4 either has a bent valve or headgasket issue.

[Kingtal0n]

He probably rented the compression tester from autozone. Those things are so used that Ive always gotten 90psi on good cylinders. I used a snapon compression tester and got 165 psi lol. Id just look for consistency. So your #4 either has a bent valve or headgasket issue.

exactly, I took a car there a few weeks ago with a friend's car. We pop the hood, I yank the plug out in 30 seconds, pop the tester in, and crank.

The compression tester says "30psi" and I just snort and start packing it up.
"Oh my god the engine is bad?" my friend starts getting worried "OMG 30PSI!"

I calmly walk back into the autozone, shaking my head.

[RussianSyndicate]

just by reading the the very first post, i know your piston rings are bad. Do a compression test and then a leak down test to determine which cylinder and the reason why its misfiring. I bet you 50 bucks its the pistion rings.

[burnsauto]

Bets aside, Lets figure something out. We have 3 out of 4 cyl. running, correct? You say the plug in cyl. #4 is wet when you pull it, is it wet with oil, or wet with fuel? If fuel, congrats, at least this can be ruled out. Have you done a spark test to find that out? I'm not sure if you mentioned it (I did a decent skim of this post but I may of missed that). If not, def. do that before you do anything else. Do the simplest things fist, then move forward. A compression and leak down test can come after you've ruled out the fuel and ignition portions of combustion.

[Banana_Cute]

Here is the update.

Car does collect milky residue under the oil filler cap, and the coolant level on my reservoir slowly decrease. My oil level does not. And white smoke on high rev's have this funky sweet smell..

I'm leaning towards headgasket. Alot. but hopefully that is all that needs to be done. I'm sending the car in for proper diagnosing, leak down and compression. Will get back and bump this thread when I do so.

[burnsauto]

yeah it sounds like a head gasket (hopefully it's just that).