Jump to content
SAU Community

Recommended Posts

Ok, it's a long read and I am trying to include as much detail as possible. Please read and help!
So I have been racking my brain for way longer than I would care to admit to, I've read probably hundreds of threads from all over the internet and still have no idea what is wrong with my car.

Background info.
R32 GTR engine swapped for R33 RB26 which had been built by Mercury Motorsport a few years ago and saw seldom use since then.
Engine was running when it was removed from the previous owners vehicle. Sump and cradle were removed to sight internals. Bearings replaced with Cosworth items.
Engine was installed into my car after receiving a few additional parts (see below)
First start up was relatively smooth, built up oil pressure, cranked, started, coughed a bit, knock sensors were not in, this was on a Nistune ECU.

Car info before swap
R32 GTR
R32 RB26
GT2860R -7's
Standard AFM's
Siemens 610cc injectors
Walbro 460LPH pump
Turbosmart E-Boost street

Nistune ECU tuned by MRC Dyno

New Parts
R33 RB26 built by mercury motorsport (forged internals)
Tomei 260deg 9.15mm lift cams
Tomei valve springs
Tomei cam gears (set to 0/0)
Ross Harmonic Balancer

After the initial start up (which I believe this issue was still present, just masked by holding revs around 3k) the car was left for several months.
Nothing significant changed. Battery was replaced, new fuel added, oil and fuel filters changed.

The Issue

The engine will crank, but either struggle to start or cough and die.
Holding a constant throttle the engine will start, sit at approx 1,200rpm, cough a lot and then do one of two things.
Either A. Start firing sporadically incl. firing so early you can hear it firing back into the plenum!
or B. Randomly kick up it's revs, anywhere between 2,000 - 4,000rpm with no extra throttle input at all.
Both of these scenarios usually result in me turning the car off which then results in a loud pressure release sound (nothing venting externally) and me crying quietly in a corner.

Things I have tried
Unplug AFM's = No Change.
Resoldered AFM's = No change.
Unplug 02 Sensors = No change.
Replace Crank Angle Sensor = No change.
Replace igniter module = No change.
Rearrange coil packs = No change.
Replace coil pack loom = No change.

Replace spark plugs = No change.
Replace Nistune with Power FC = No change.

Please. Help?

Edited by PitlanePhotos

Are either of the ECUs tuned for the 610cc injectors? Also how is your base fuel pressure and or fuel dampening (if any)?

Btw, Nistune needs the knock sensor flags disabled if you're going to unplug them as you've done

Are either of the ECUs tuned for the 610cc injectors? Also how is your base fuel pressure and or fuel dampening (if any)?

Btw, Nistune needs the knock sensor flags disabled if you're going to unplug them as you've done

The Nistune was tuned with the 610cc's. Ran for 2 years with them. The power FC has had the injector %'s and latencies changed to suit.

Fuel pressure is approx 3bar, in tank regulator has been removed, fuel rail reg remains.

The car was run with the nistune, with knock sensors both connected AND disconnected.

And swapping to the Power FC made no difference so I don't see the issue being with the nistune (although it would have been nice and simple)

Power FC does not read any knocking when idle, but does register a tiny amount when the engine is coughing and spluttering as you would imagine.

Are your fuel lines all hard braided Teflon hoses?

Also do you have a wideband connected?

Not braided. But fresh E85 rated hose.

Fuel is BP ultimate though.

I do not have a wideband connected unfortunately.

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

    • Bloody Skylines, they put you through the bloody wringer! Stick at it! Stunning drag strip BTW! Where is it? Can see part of the name on the slip and probably should just Google it!
    • I mean the other day I had to walk someone through diagnosing why their timing belt was walking off the cam gears. At least one of the issues was a bent tensioner stud. Local mechanics have found runout on the CAS mechanism causing weird failures. I'm also no saint here I've documented some of the things I've had to learn the hard way. Something I discovered recently is that my CA emissions catalytic converters weren't even welded correctly to align the downpipe to the main cat and they tossed the support bracket that goes from the transfer case to the downpipe to support everything there. I spend a lot of time chasing down these decidedly unsexy problems and the net effect is it feels like I never actually get to the original objective (flex fuel, VCAM, oil control, cooling, etc).
    • At times with how you make everything sound, all I imagine Americans doing when they see a gtr is standing there looking at it and bashing it with a gun like how a caveman would with a club and hoping it fixes itself 
    • I think this is just a product of how the US market works for this stuff. Shops are expensive and there's no real way of knowing what kind of results you're going to get, people don't really have the institutional knowledge. I have heard too much at this point to really put faith in anybody "full service" except maybe DSport and they aren't really a full service kind of shop. If you go to the right place I have no doubt they'll get it right for you. Some locals have set it up right but the cost really is nuts and even now they're still fighting issues. And you know I'm a crazy person who thinks things like twin scroll, relatively short low-mount cast headers, PCV recirc to intake, recirculating BOV, right-sized for ~400 whp, MAF load, validating all of that to a standard comparable to OEM test programs, etc are relevant. For what it's worth, multiple local owners at this point have been stuck in a perpetual cycle of blowing a motor -> getting someone to rebuild it -> some missed detail causes the bearings to wipe and spin just outside of break-in mileage or drop valves or some other catastrophe -> cycle repeats. I usually only find out about this because I'm perpetually helping random friends with diagnosing car troubles, Skyline or otherwise. The single turbo stuff if I'm honest is mostly secondary, it just doesn't seem to achieve the numbers in the ~2000-3000 rpm region that I would expect given the results I've seen here or in Motive's videos. I don't really know what we're missing here in the US to be causing this. Lots of people like to emphasize the necessity of finishing the project first and foremost, but I'm not made of money and I can't afford to be trashing a 15k+ USD engine build with any regularity. Or spending my relatively limited garage time these days unable to triangulate problems because too much was changed all at once. Also, even if it isn't a catastrophic failure I would consider spending the cost of single turbo conversion with nothing to show for it to be pretty bad. 
    • The water pump is know to leak as well. So if the coolant is low checking that first as well as hoses. 
×
×
  • Create New...