Car Won't Start!

[dontyellpl0x]

Oh man... That sucks hard. Sorry to hear that

Have you done a compression test before? Is there a slight chance you did it wrong?

Edited August 20, 2013 by dontyellpl0x

[Got a Pulsar]

I demand a Re-test !!!

was that with or without a little oil in each cylinder?

[Manuel Kasko]

It was without but we did the same test a few weeks back and got the 150-160

I'll give everyone a break down of how I did the test and I don't think throttle matters in this situation.

-Unplugged injector plug.

-Removed all spark plugs/coils.

-Got the compression tested and wound it into the cylinder.

-Turned the key over until it reached peak PSI and then stopped.

-Recorded said PSI and moved onto the next cylinder.

[Pattey21]

if you did a compression test without the battery fully charged it will throw results!

[Got a Pulsar]

This sounds good. ^^^

Batty was definately down by a couple of Volts, but turn the engine fine, Headlights worked etc...

How was the car last driven?

Easy duties or Fully Thrashin' it?

[Manuel Kasko]

I think we have to admit it couldn't throw results that bad.

To go from something like 160 to 25 is a massive drop.

Then for the cylinder tested after that to be 90 just wouldn't make sense.

Also we tried to jump start it and it wouldn't start so the battery is not the problem haha.

[Got a Pulsar]

Yes But low voltage Batty...

[Pattey21]

dont stress to hard till you do it properly. charge that battery to 12.6v make sure you.threads are clean for each cylinder and that the compression tester is seated and tight on each plug. make sure the cylinders are not completely dry using a few drops of oil or injectors still plugged in.

have to eliminate variables to get solid results.

same with jump starting, rating of leads, clean connections on both problem and donor car, donor car raising the revs to 2kish when trying to start, also problem cars voltage cant be too low either as it still wont kick. (not everythings black and white)

[chus13]

If your engine is cold, then you are going to get really low compression test results. I tested my car the other week without warming it up to operating temperature and got really low CT results, ~120 psi. It had me worried, but it should be around ~160 when it is warm and the tolerances have tightened up.

Edit: Didn't see the 25. thats a bit too low

Edited August 20, 2013 by chus13

[D.I.Y. Mik]

Head gasket?

check for oil in water and water in oil

You could do that in a few hours if theres no head warping, trojan prob have a gasket on the shelf

re test for sure

Edited August 20, 2013 by D.I.Y. Mik

[TiTAN]

those numbers are too low double check that the tester was sealing correctly or that there isnt something wrong with the tester (try it on a known good engine), also compression tests are done with the throttle completely open (foot to the floor).

stick the battery on a charger or do the test with jumper leads connected to another car so it has some decent volts while testing.

[StinkyPoo]

I can still come and take a look. Otherwise I might buy the wreck off you

[zebra]

Bloke in the fi section had the exact same problem.

Was the nvcs (vct) replaced it and all was well

[zebra]

http://www.skylinesaustralia.com/forums/topic/428705-rb25-neo-misfire-low-compression-all-6/

[Manuel Kasko]

Thanks again guys

Okay so I'll try a re test tonight and do it with open throttle. Also stinky if you are free this afternoon that would be great if you could swing by with some r33 parts and jumper leads?

If not I could borrow a car possibly and come borrow parts off people

Already got a tool box off Bryce and comp tester off Verms haha

[Duncan]

on the down side it's not impossible to suddenly break a timing belt. how many klm ago was it last changed?

Still, I'd redo the test first with jumper leads connected to a running car.

[Manuel Kasko]

Timing belt has not been changed since I have owned it. And I have had it for about 45,000km

Not sure when it was previously changed

What would happen if that was to break?

Does it still do huge damage at idle when something like that happens?

[Trozzle]

Timing belt breaks > nothing governing camshaft rotation > pistons mash valves.

If your timing belt broke you'd probably have heard horrible sounds as the pistons slammed into valves, rather than it just conking out like you indicated.

I'm still thinking something electrical...if the timing belt snapped and it mashed valves, given one cylinder is significantly worse than the others I'd like to think there should be at least 1 cylinder that reads almost normal (valves closed and intact)

[Anfanee]

Dude im sorry to hear that. I thought the same thing when we tested my engine, running ZERO PSI on 2 Cyl and about 10-20 on the other four. It's a shame i didn't take photos of what was left of my pistons when the engine was pulled apart.

Honestly id just pull the head off and check it. Hopefully its a gasket but it sounds like something more important. Just get a $1500 engine and swap your parts over. Maybe even find a whole 33 for like 2-3k so you have a full parts car.

[Trozzle]

I'm hesitant to suggest gasket as it'd be a bit unlikely to fail across every cylinder wouldn't it? I'd have thought once it blew the weak spot out, that's it and only the cylinders that needed that bit of the gasket to seal would show low compression....also if it failed on this scale, you'd be guaranteed water in the oil system and visa versa.

I should point out everything I suggest is just speculation. I've never dealt with engine failure or anything close to this scale of fail, so I'm just relying on my firm grasp of internal combustion engines and what effects what, particularly with RBs If I wasn't such an academic failure through school (thanks to giving almost literally NO f**ks for it), I'd be a pretty bloody decent mechanical engineer lol....just the way my brain is wired....unfortunately I'm just lazy and have next to no attention span for things that don't interest me