SR20DET: No Start, Bad Compression, Black Spark Plugs...

[5280VertDET]

Ok. I have read about blown rings and rebuilds and all the other fun things, but my numbers are a little odd...

EDIT: Never smoked, trace amount of oil in intercooler (probably from an older and incorrect catch can, on motor for 30 days), cant see any coolant on dip stick and from what I can tell the cylinders are black (see the spark plugs below).

I will be draining the oil and dropping the pan to look for pieces later this week.

Here's the run down:

Left work, warmed engine for 2-3 minutes, heard a "thawhap" bogged and lost power.

Upon further inspection, the coupler before the intercooler popped off. reconnected it and attempted to start, turned over and no start. Rolled it back to work thinking it was just flooded. No problem, came back the next day and it would start again. Towed home and tested fuel and spark, all good. Read a bit on here, compression tested as such:

WOT
1: 120
2: 60
3: 60
4: 30??

I hoped that the gauge was broke, it was... whew...

Got a new and different compression gauge and re did the test:

WOT:
1: 60
2: 30
3: 30
4: 30

Results were 10-15 PSI higher on a "wet test" using a cap of oil in the cylinder.

Thoroughly confused because prior to the coupler popping off it was running and starting fine...

Also, these are my spark plugs:




Question, what's next to determine what is going on? I was thinking about getting a leak down test, but I don't have a compressor... and I don't really want to rip the motor apart just yet.

I just don't know how this happened?

[KoukiMonsta]

First, give us more info.

motor, modifications, previous history you feel might help me help you.

With those compression numbers, I wouldn't think you problems occurred 'over night'

blowing an IC coupler off should not be a big deal...unless you suck a dead cat into the manifold.

drain your oil - easy and cheap. does it look like gas, coolant, oil, or baja blast?

EDIT: leakdown test is very useful. even a cheap ass harbor freight rig to pump air in the cylinders and listen for leaks can help. As for the compressor..friends, neighbors, etc if your lucky.

[5280VertDET]

Originally Posted by KoukiMonsta

First, give us more info.

motor, modifications, previous history you feel might help me help you.

With those compression numbers, I wouldn't think you problems occurred 'over night'

blowing an IC coupler off should not be a big deal...unless you suck a dead cat into the manifold.

drain your oil - easy and cheap. does it look like gas, coolant, oil, or baja blast?

EDIT: leakdown test is very useful. even a cheap ass harbor freight rig to pump air in the cylinders and listen for leaks can help. As for the compressor..friends, neighbors, etc if your lucky.

Thanks for the reply.
Everything is stock SR swap, 3in turbo back, FMIC, Boosting only to 10PSI stock ecu, maf, injectors...


I agree, I dont understand, compression like this should not have occurred "overnight"... Thats whats perplexing me the most, she was running like a dream before that.

The only thing that I can think of is that maybe the MBC caused a wicked spike... but I wasnt even at WOT when the coupling came off.

Anyway, oil will be dumped on Thursday... I'll snag a compressor and leakdown tester at HF too... ugh.

[jr_ss]

Pull the valve cover and check cam and mech timing. My guess is your motor jumped time and now your cam/s are out. This could mean bent valves as well.

[cotbu]

In all honesty, with compression numbers like that, the next course should be a tare down. Anything could have happened and most of those things could happen in an instance. I agree with removing the valve cover ,but jumping timing is highly unlikely. Best bet would be rocker arms out of place.

Looking at the plugs, looks like oil contamination, but could be just a rich condition from blowing the coupler and then not idling stoich long enough to clean the plugs. (Can't determine the texture).

If you happen to remove the head, you might see a clearer picture of what happened, if you didn't throw some rockers, that is.

Sent from my Highly Tuned Note4!!!

[5280VertDET]

Originally Posted by cotbu

In all honesty, with compression numbers like that, the next course should be a tare down. Anything could have happened and most of those things could happen in an instance. I agree with removing the valve cover ,but jumping timing is highly unlikely. Best bet would be rocker arms out of place.

Looking at the plugs, looks like oil contamination, but could be just a rich condition from blowing the coupler and then not idling stoich long enough to clean the plugs. (Can't determine the texture).

If you happen to remove the head, you might see a clearer picture of what happened, if you didn't throw some rockers, that is.

Sent from my Highly Tuned Note4!!!

Thanks! That's the kind of information I am looking for, given my description. I will rip in to it next weekend... life gets in the way and this is moving down the list.

[army240]

There is not a lot of thing that could affect compression on all cylinders at once. Throwing a rocker arm would only affect the cylinder that the rocker poped off, and it is very unlikely that you threw 4+ rocker arms at the same time.

Also, a cracked piston could affect compression on the cylinder that the piston is cracked... also very unlikely that you cracked all 4 pistons a the same time!!!

So I will leave to option here :

How far did you run with you IC coupling disconnected? Driving with a rich condition for too long could glazed the cylinder walls therefore causing low compression, and oil fouling on the plugs.

My other bet would be on the mechanical timing. Camshafts are a common points on all cylinders. If you retard or advance it (like skipping teeth) this could affect compression on all 4 cylinders. Also, you could have bent valves from this problem, which you will need to check if you timing is not correct.

I hope this help!

[5280VertDET]

Originally Posted by army240

There is not a lot of thing that could affect compression on all cylinders at once. Throwing a rocker arm would only affect the cylinder that the rocker poped off, and it is very unlikely that you threw 4+ rocker arms at the same time.

Also, a cracked piston could affect compression on the cylinder that the piston is cracked... also very unlikely that you cracked all 4 pistons a the same time!!!

I agree, that's what is so weird compression results...

Originally Posted by army240

So I will leave to option here :

How far did you run with you IC coupling disconnected? Driving with a rich condition for too long could glazed the cylinder walls therefore causing low compression, and oil fouling on the plugs.

My other bet would be on the mechanical timing. Camshafts are a common points on all cylinders. If you retard or advance it (like skipping teeth) this could affect compression on all 4 cylinders. Also, you could have bent valves from this problem, which you will need to check if you timing is not correct.

I hope this help!

As soon as the hose popped, engine sputtered flooded and I turned it off, so maybe 10 feet and a few seconds later.

I hope it is something like timing I don't here any metallic noises from the engine, and my compression numbers weren't helpful. I will be going through it next weekend in more depth.

I REALLY APPRECIATE everyone's help too. I am just trying to gather as much information from other threads and you guys before I dive in to deep.

[cotbu]

Get that valve cover off, and rotate the engine to tdc, by hand. Listen, look and feel.


Sent from my Highly Tuned Note4!!!

[5280VertDET]

Originally Posted by cotbu

Get that valve cover off, and rotate the engine to tdc, by hand. Listen, look and feel.

Will do! Thanks. Just need some time now! Wife, 8 month old and work, man, it's different now.

[lucas240sx]

any update on this?
ive been waiting

[5280VertDET]

Originally Posted by lucas240sx

any update on this?
ive been waiting

Me too, with a week long business trip and family life I haven't been able to get to it. This weekend, yes, this weekend...

[Rusker]

Curious to hear what you end up finding. Good luck!

[cotbu]

Op, should be going through withdrawal about now, especially if he has a Honda beater or truck of some sort!

From a Highly Tuned Note 4.5!!!

[Dboyizmlg]

I guess there's a couple people curious to know what happened here.... Lol

[5280VertDET]

HAHA, thanks guys, sadly had a small family emergency last weekend which took that away and between work and my wife working grave yard I am not getting to it anytime soon. Not to mention work travel, again, next week.



I will probably be dropping it somewhere this week or in 2 weeks when I get back and someone take a look; single car family life sucks and so does light rail to work (albeit faster)...

So, stay tuned, OP will post something in the next 1-3 weeks.

[5280VertDET]

Ok. The verdict is in.

I dropped it off at Japanese Specialties in Denver with Matt.

He ran a compression test and leakdown.

0 Compression on 1 & 2 with complete blow through on the leak down.

60PSI on 3&4.

His thought is that there was boost spike, hence the coupler popping off, and it leaned it self out ruining cylinders 1 & 2. There is visible scoring on the walls as well.

There you have it, complete bottom rebuild with possible top end work. His recommendation is a new long block.

So, I got that going for me. FML.

[TurboTiger]

Ouch.

Are you going to rebuild? Crappy situation you're in with only one car.

[5280VertDET]

Originally Posted by TurboTiger

Ouch.

Are you going to rebuild? Crappy situation you're in with only one car.

Ordered a OEM rebuilt motor that was built by the SR20 Store from Mogli at 9K racing. Should arrive this week.

In the meantime I an re-routing the wiring harness and got a sweet deal on some Tomei Cams, ISIS3871, Freddy Intake with a 70MM ETA1 throttle body, z32 MAF and some 550s. Need a tune and a free weekend.

ETA: June 1st completion date.

Also waiting on mt garage to finish being built so I have the proper space.

[TurboTiger]

Awesome.

You should rebuild the old one for a spare!

[5280VertDET]

Originally Posted by TurboTiger

Awesome.

You should rebuild the old one for a spare!

Thats the goal, maybe ever throw it in a S12... Who knows...