Jump to content
SAU Community

Recommended Posts

Hey guys have an rb25 neo.

The problem is it won't idle, feels like its lost all power.

Misfiring like no tomorrow from word go.

It's a fully built motor adjustable cam gears VCT etc.

So far..

I've changed plugs changed coil packs.

Checked harness injectors etc still no luck.

Readings from compression test:

1 50

2 51

3 50

4 50

5 49

6 53

Could the timing have jumped out and cause such low compression ?

It's also running a 2 mil steel head gasket.

thats way too low.. does it go up when you do a warm test? i spose its hard to tell if it doesnt even run.

has it been like this since it was built? have the correct pistons etc been used to work out the CR?


Do a leak down test also

Literally got it off the dyno a week and a half ago didn't miss a bear then threw an intercooler pipe off the cold side of turbo then ever since then all over the place misfiring.

Never missed a beat previously.

Motor since build has only done 20,000 tops. Doesn't get molestered either always roll on power.

When car warms up it manages to hold idle.

Still missing and gutless as all hell when accelerating but can idle.

Tried posting photos of cam gears and alignment but won't allow me to through app ...

I second that a Leak Down test would be in order.

Low compression highlights a possible leak, whether it be the valves, pistons or headgasket etc.

I put my second hand engine through a leak down test at the workshop for assurance before purchasing. It's a quick affair, and relatively cheap.

Sorry guys been hectic at work will be doing it all on Saturday correct timing first tdc compression test theneak down and hope like hell compression returns..

Definitely will post results

  • 2 weeks later...

Yea it was freshly dyno'd as I had to fix turbo gasket. Just downloaded software for vipec and hooked in.

The tuned advanced way to far. About 6 degrees advanced basically the whole way very odd

  • 3 weeks later...

Sorry bout the late update so timing and everything's was fine.

So did a hit more hunting could not hear the click of the vct module. Found it had blown.

Replaced it and wow she's alive..

Positive things found out from jhh engineering and a few other people responsible for building this my compression is 110 which returned.

Put it back on the Dyno with a bit more boost and at 18 pound it made 518whp.

So now changing it to e85 and upgrading the supporting fuel mods.

Should be interesting.

Thank you so much to everyone's comments and suggestions.

Hopefully can create a log of my journey from unleaded to e85 (flex fuel)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Can't you put the pistons to TDC and then do the valve seals? Or will the drop down too far to pull them back up?
    • One thing I can tell you is, do it properly the first time. If you encounter unexpected problems just let the car sit for a week or two if you have to get some other parts or figure stuff out.  I'd have said go and use as many OEM parts as possible but since you want to change the turbo later on a custom kit is probably the better choice. Since I have no experience with RB25 just compare parts diagrams and images before buying a line kit and it should be easy to see if it has everything you need. Amayama has very good parts diagrams and part number lists, that is what I used a bunch to figure out what I might need. And don't forget to plan ahead and possibly renew other stuff that's easy to get to while you're in there doing the turbo lines. Happy wrenching
    • Update 4:   Hi all, good news. Engine is running and all the gaskets and seals seem to be working as intended. No leaks so far, even the JB Weld seems to hold. I flushed out the old coolant a few times and put in fresh coolant, not Nissan stuff, I decided to try the Ravenol Protect FL22, they claim it works for a wide variety of JDM cars and the opinions on it by some people were pretty good. And it has the nice poison green color! And man am I glad I bought a coolant system tester earlier this year, vacuum filling works wonders on this engine. I can definitely recommend this to anyone still doing it the old school way. All you need is compressed air supply. Will have to do a small test drive as soon as I can, I removed the gauge cluster again as the tacho needle was still bouncing around a bit but it was much better than before already.  I also found some cracks on all 4 tires inner and outer sidewalls. Apparently these tires should 't be parked on for extended periods or be kept under 0 degrees during storage, which I did not know. Clearly the previous owner didn't look into those details either, he probably bought them just cause they are cool semi-slicks. I'm just wondering how tf I am supposed to reach 30-80 degree tire temperatures on the public road consistenly, these tires were never going to work for my use case. I'll probably order Continental SportContact7 ones as these are the best allround summer tire available right now and I don't think I'll need anything crazier for now. Do let me know if you have experience with various tires and which ones you recommend.
    • You have no idea how many goddamn boxes I received these past three months haha Most have been put to use by now though, luckily
    • Not going to pretend I didn't do a bit of junky work this time around, but mostly due to the fact that some things I am not willing to spend days fixing right now, like wiring. I try to do most things properly the first time around.
×
×
  • Create New...