Rb25Det Neo Stopped

[Captain Wow]

Hey all,

Driving home this morning, car seemed to be running well. Started to come on boost a little bit and the engine had a little shudder and didn't feel right, started producing a fair bit of white/grey smoke so I slowed down to pull over and the rev's dropped right down and the engine died.

Got towed home and have been over it. Intake pipes are clean, turbo appears to be in good nick, timing is all lined up, can crank over with hand. Hasn't lost water or oil and has plenty of fuel.

After I'd gone over it I had the coil packs unplugged and turned it over and it seemed to be turning over alright but then the whole engine locked up with a reasonable good thump. Wen't over it again, plugs out, manually turning over all was well. Put plugs back in and turned over with the key and same result with the locking up.

I'm a little stumped now and I have the feeling like it's going to be something highly undesirable that is up.

Anyone care to have a go with diagnosing this?

Cheers,

- Lance

[KiwiRS4T]

Cam belt?

[Captain Wow]

How'd you mean? I've taken the top cover off to check the timing marks. Had good tension and appeared to be in good nick.

- Lance

[chef_stagea]

Locked up with compression cycle or banged to a stop? The only bang will be piston to spark plug really. And uve rulled that out.

[Scriblez]

Stupid question man, but have you checked your battery Voltage? I had a similar issue a few months back and it turned out that my battery dropped a cell while I was driving. Doesn't really explain the smoke, but could explain the lack of crank. New Yellow Top fitted now, all is good.

Just food for thought..

[Captain Wow]

It's hard to tell why it stops. It cranks over for a second or two but sort of thumps to a stop. Enough of a thump to physically shake the engine a bit. It's not a great feeling or sound so I'm a little reluctant to keep doing it. I might take out the plugs and disconnect the fuel pump and see if I can crank it over without issue.

Yeah, I've checked the battery. It's a matter of a few months old but it's usually one of the first things I check just incase. Cheers anyway.

- Lance

[Scriblez]

Shit man, doesn't sound like your day! Keep us posted, keen to know what the problem is myself now!

[533 RYC]

Lance, sorry mate, but by the sounds of the engine locking while cranking, it's hydraulic locking (you can't compress a liquid).I don't recommend cranking the engine anymore with the spark plugs in, or you will smash a piston &/or rings. I reckon it's head gasket time mate. Try some of these things:

Remove the spark plugs.

Keep them in order.

Look for either a WET or CLEAN spark plug.

Do a compression test.

Buy a cheap inspection camera (boreoscope) to jam down the holes & look around.

Decent figures should be around the 150psi mark.

[Captain Wow]

Hey mate. I had hydro locking in mind, which is why I stopped the cranking lol.

From memory, number 5 cylinder plug was wet when I pulled them out today. I did check down the spark plug hole with a torch but couldn't see a lot so a boreoscope is the way to go.

I was going to do a compression test tomorrow as I've had an overheating issue a while ago, though it's not been using any water even with a couple of long trips under it's belt since. However it's something I will check anyways.

I'll have a bit more time tomorrow to look into it properly with the right tools and things you've suggested.

Thanks a lot for your help,

- Lance

[PN-Mad]

Might have a stuck injector, causing the overfuel and locking?

Timing mark meets up with TDC? Hasn't skipped teeth on the timing belt?

[533 RYC]

Over heating issues aren't good.

Shit happens.

Recently my wife's Cube didn't start one Monday morning (wasn't used all weekend). When I heard the way the engine was cranking I knew it had dropped a cylinder. Blown between 1&2. both cylinders were a perfect 82psi.

It drove perfectly as I was the last to drive it & it had never had ANY issues with overheating.

Spose now is the time to be thinking of upgrades!!!!!!!!!!

[Captain Wow]

Might have a stuck injector, causing the overfuel and locking?

Timing mark meets up with TDC? Hasn't skipped teeth on the timing belt?

Haven't checked for stuck injector (don't know how just yet) but I will figure out how and put that on the list of checks.

Timing all lines up if I'm correct in assuming that the first mark on the left on the harmonic balancer is T.D.C?

Over heating issues aren't good.

Shit happens.

Recently my wife's Cube didn't start one Monday morning (wasn't used all weekend). When I heard the way the engine was cranking I knew it had dropped a cylinder. Blown between 1&2. both cylinders were a perfect 82psi.

It drove perfectly as I was the last to drive it & it had never had ANY issues with overheating.

Spose now is the time to be thinking of upgrades!!!!!!!!!!

My electric fan stopped when the Mrs was taking the Stag out for a drive so yeah, shit happens lol. I though I'd been lucky enough to get away with no damage but it may transpire that I wasn't quite so lucky. Ah well, it's all part of the game with cars.

[KiwiRS4T]

Haven't checked for stuck injector (don't know how just yet) but I will figure out how and put that on the list of checks.

Timing all lines up if I'm correct in assuming that the first mark on the left on the harmonic balancer is T.D.C?

Yes that's right. Timing is here:

http://www.skylinesaustralia.com/forums/topic/73824-adj-camshaft-pulley-new-cam-belt/

Suggest you pull the plugs out and try turning it over by hand and you should be able to see if any cylinder is hydraulicked

[Captain Wow]

Ah brilliant! I was looking for a timing guide but hadn't sourced one, cheers Bob!

I'm unsure of what to check for in regards with hydro lock. I'll do some research unless you have some advice?

- Lance

[KiwiRS4T]

Well a cylinder can only be filled with oil (not likely) petrol - possible but you should smell it as soon as you pull the plugs out - or water - blown head gasket and/or cracked head. If you take the plugs out and turn the engine over (with a remote switch on the starter or pref by hand) you may see some of the offending liquid come out the plughole. Are you losing water from the radiator? Does there appear to be water in the oil (or oil in the radiator)?

My other idea is faulty CAS or damaged CAS drive on the end of the camshaft.

Good luck!

Ah brilliant! I was looking for a timing guide but hadn't sourced one, cheers Bob!

I'm unsure of what to check for in regards with hydro lock. I'll do some research unless you have some advice?

- Lance

[Captain Wow]

There was a reasonably strong smell of fuel and I didn't see and oil upon my quick inspection with a torch down the spark plug hole but I'll check again while turning it over tonight.

Water level is staying constant and no water in oil or oil in water that I can make out. However I'll Tee Kay test anyways.

I did have a quick look at the CAS when I took it out and physically it seemed fine but I do have a spare that I could also try.

Cheers,

- Lance

[Captain Wow]

Righto, hydro lock is the winner I turned it over by hand when I got home this afternoon and number 4 cylinder erupted with fuel. Fingers crossed that rings and rods are still okay with a couple of false starts under it's belt. I'll compression test it once I've got the over fuelling sorted.

I'm going to assume that the injector is leaking as I didn't notice an excess of fuel yesterday when I was turning it over but over 24 hours there was a clear build up of fuel. Can anyone confirm what these injectors are? I was told they were out of a 350Z.

Cheers,

- Lance

Edited August 5, 2013 by Captain Wow

[PN-Mad]

Oh yeah!

Winnah!

Nope doesn't look like a 350z injector. Are you sure they aren't stock? 350z would be smaller than rb25det

[Captain Wow]

I got hold of the chap I purchased the car off and asked him what injectors they are. Apparently they're VQ35 decaped injectors that are flow rated to 550cc. Not so keen on decaped so I'll keen an eye out for some legit replacements.

I sent the injectors off to the cleaners yesterday and picked them up this morning. Number 4 (the offending cylinder) injector was stuck open and was blatantly pouring fuel out so they've put it through the ultrasonic cleaner and it's come up good. He also told me he's put bigger filter baskets in them so that should be great.

I'll get the compression tester onto the engine tonight and check the health of the engine (fingers crossed) Then hopefully put her all back together and get it up and running.

Cheer for all the help guys, and I hope not to have to carry on this topic haha.

- Lance

Edited August 6, 2013 by Captain Wow

[533 RYC]

Oh yeah!

Winnah!

Nope doesn't look like a 350z injector. Are you sure they aren't stock? 350z would be smaller than rb25det

Spot on Alex!

Stuck injectors are not that common - especially for white/grey smoke!

All running good now Lance?