Jump to content
SAU Community

R34 Gtr Strange Problem

Don Dada

By Don Dada,
in Engines & Forced Induction

 Share

Recommended Posts

Don Dada Mentor

Don Dada

Posted
Posted

I'm getting a rough idle problem with a 34 gtr and I have tried basically everything without sucess.

First off the car has a r33 head&blk using back the 34 harness with some unknown cams, which I believe are 34 as well as it uses back the 34 type cas

When idling if I pull the connector for the coil pks I can hear a noticeable difference in the beat of the engine on all except no. 2, so i'm assuming the problem is with 2.

Checked for spark...good. Switched around pks and plugs same thing. Checked for inj pulse....good. Changed with a next set of inj and same thing.

Changed afms same thing, changed resistor pk same thing, changed cas same thing. Checked timing and dots on gears line up with backing plate while crank pulley is on the first orange mark 0* so I assuse everything is good there.

Compression test 150-160 with the highest being no. 2

Dont think its an electrical problem the spark from no.2 seems healthy and test light looks the same for all inj when checking for pulse.

Is r34 gtr cams compatable with the r33 gtr head?

What you guys think?

Link to comment
https://www.sau.com.au/forums/topic/404466-r34-gtr-strange-problem/
Share on other sites
XKLABA Grand Master

XKLABA

Posted
Posted

the only difference between 32/33 and 34 cams is timing and the CAS key, otherwise identical and heads are the same right through

try spraying brake cleaner around the intake runner on number 2 and see if the idle changes, try compression test with throttle closed as well as open

have you tried changing the CAS,

but generally if you have fuel-compression-spark then you should not have a problem, so interesting, hope you find it

keep us posted

GTRNUR Grand Master

GTRNUR

Posted
Posted

Your on track with your troubleshooting, but have moved down the wrong path a little.

A vacuum leak around number 2 would cause it to burp and pop at idle a little, but not flame out completely. A faulty cas also would not drop the same cylinder consistently. It would be doing it on all the cylinders or not run at all.

Does it rev cleanly and crisply, or does cylinder number 2 never appear to fire.... Or is it only drop ignition on Cylinder 2 at idle?

What is the idle speed?

Is there a noticable drop in RPM when cylinder 1 is unplugged, and did you PROPERLY balance your throttles when connecting your throttle linkages.

Does it do this cold as well as when hot?

Last of all... is it losing coolant, and is the number 2 spark plug clean or wet when its removed? If its wet see if it will evaporate instantly to dry if you blow on it (indicating fuel), or not (indicating coolant/water).

GTRNUR Grand Master

GTRNUR

Posted
Posted

I'll get some carb spray and check for leaks. If is was a matter of valve clearance, would be be isolated to no.2 as is now?

Yes

Its possible that variation in clearences or impropper shimming of the bucket could hold valves in one cylinder open, but that would also be evident in a compression test. It would test lower than the others, not higher, so I would be inclined to think not.

Don Dada Mentor

Don Dada

Posted
  • Author
Posted

Idle is 900-1000rpm and it does not rev out clean at all hot or cold. The plugs appear to be consistent across all but does come out a little wet, doesnt seem bad

When you unplug no.1 you definitely notice it as it wants to cut off, and basically no change when you unplug no.2

The car was bought recently and did notice the temps climbing, but havent driven it long enough to notice any coolant loss. Also tried bleeding from the 10mm bolt on the balance tube but that was clogged so just left it at that until I sorted out this problem.I havent noticed any coolant and oil mixing though

I'll have to take another look at those plugs though and check to see if that little wetness is infact water or if its fuel across all

GTRNUR Grand Master

GTRNUR

Posted
Posted

Sounds like a pretty solid fault. You need to confirm fuel or water on that plug.

You can eliminate fuel by disconnecting the injector for that cylinder and starting the motor for a moment with no plug to dry the cylinder. The install a clean and dry plug, re-start and idle for 30 seconds or so. The stop again, remove and inspect the plug.

How did you check the ignition for the cylinder was working ok?

Don Dada Mentor

Don Dada

Posted
  • Author
Posted

Yea...Will diagnose with a new set of plugs.

As far as checking ign, I took out the coil attached a plug and checked spark which looked healthy, and was same when compared to other cylinders using the same method.

Also swapped around pks and plugs....splitfires btw

DVS JEZ Grand Master

DVS JEZ

Posted
Posted

Spray wd40 along the plenum gasket. U will find ur problem.

Had to replace the inlet gasket on a 32 GTR the other week for this exact reason. My smoke tester proved my theory.

Had a constant miss in cylinder 2. Disconnect coil no difference. Disconnect injector slight difference. Spray wd40 or similar and idle cones good. Replaced with Nitto gaskets. Runs perfectly now.

4e3966ce.jpg

Don Dada Mentor

Don Dada

Posted
  • Author
Posted

Hmmm....Interesting. Will definately try that, just that it seems like the fuel pump has now shit itself....Actually not even sure.

Added some fresh fuel to the car as it was parked up a couple mths and after that it barley starts and idles. Pulled the return to the tank and no fuel, so we went inside the tank and found a walbro pump, took it out and hooked it up front plumbed to the rail in a container of gas and it works.....pressure in the return, but the car barley starts. Tried an oem gtr pump up front and same problem.

So the plot thickens. Done troubleshooting for today, and until I get a fresh set of plugs.

XKLABA Grand Master

XKLABA

Posted
Posted

Spray wd40 along the plenum gasket. U will find ur problem.

Had to replace the inlet gasket on a 32 GTR the other week for this exact reason. My smoke tester proved my theory.

Had a constant miss in cylinder 2. Disconnect coil no difference. Disconnect injector slight difference. Spray wd40 or similar and idle cones good. Replaced with Nitto gaskets. Runs perfectly now.

4e3966ce.jpg

This is exactly what happened to my 32, and is why I suggested the brake cleaner as it doesn't leave any residue and will change the idle if there is a leak

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • PotatoCake
      Has anyone put in brand new full carpet? (not floor mats)

      By PotatoCake · Posted

      Doing a refresh of my 33 and can see a few websites stating they sell the entire main carpet for our cars, but they all have generic photos which is fine, i understand they are custom made to order.  Just seeing if anyone has got it done or had any experience with this, as i would only want to do it if the fit and finish was as good as oem https://carmatsdirect.com.au/products/moulded-carpet-or-vinyl-for-nissan-skyline-r33-1993-1998-coupe https://knoxautocarpets.com.au/moulded-carpets/nissan/skyline/skyline-r-33-1993-1998/
    • MBS206
      R32 update from 1990's spec.

      By MBS206 · Posted

      Any plans for E85? If so, add flex fuel sensor.   I'd probably add in the sensors I mentioned above if the Link will support using them for engine protection. With water pressure, you need to be able to effectively set it that "If temp > X, and pressure = atmospheric, shutdown" as at running temp, you should be able to read pressure in the cooling system. If pressure suddenly disappears, it means the water went some where, and this is a quicker reaction than waiting on water temp to go up (Which, can take a little longer than you'd like, considering it now has to wait for hot air to heat it up) Oil pressure, Oil temp, both would be on my list too if you're looking to add sensors. Wideband O2. And at least one EGT sensor. If you're feeling deluxe, put in individual runner EGTs. Single EGT sensor is more so forget about a specific number, get used to "What is normal EGTs", and then keep an eye on it, if it starts going away from "normal" it's a sign something is wrong (Also, things like the tune can still start going out of spec, but EGTs may not show it, for example one injector starts running leaning, so ECU richens everything up, now 5 out of 6 cylinders are rich, and running cool, with one cylinder lean and running hotter, so it's not perfect) Then there is your other things to look at non sensor related, but you may have already done, or have underway, and that would be things like building a sump for more oil, and better oil control under high G-Forces (Cornering, brakes, acceleration). Basically, the above is worth looking/thinking about, if the ECU can do protective stuff with it, and you continue to use it how you are (Drive it to the track, thrash it, drive home, repeat once every 3 to 4 months)
    • Ty1
      Hicas ball joint install tool

      By Ty1 · Posted

      Can also confirm these work a treat for most balljoints and bushes. If you have access to a big rattle gun, they make the job so much easier and quicker, compared to using a socket wrench or shifter on the c-clamp 👍
    • djr81
      R32 update from 1990's spec.

      By djr81 · Posted

      Its sort of street but got used for circuit sprints on account of I never drive it on the road because I dont have the time to spare. So it usage was sits around for months at a time then gets driven either 50 or 250 kms to the track followed by 20 laps followed by 50 or 250kms home followed by stuck in the shed until next time. So yeah neither fish nor fowl. Just dont want to break it on the track as a preference. Hence the fairly short sensor/mod list. Probably more worried about it pinging itself to destruction more so than anything oil related.
    • MBS206
      R32 update from 1990's spec.

      By MBS206 · Posted

      My thing I'd be doing, is pulling it out, and just getting the tune cleaned up for now. Before that even happens, checking over everything, like vac hoses, fuel hoses, etc. No point dropping thousands on sensors if the moment you start it back up all the oil leaks out, or it has massive vacuum leaks etc.   But really, to know what to do, depends on what your use case is. Hard core track car? Throw most sensors available at it. Street car, I'd probably just run oil pressure, oil temps, water pressure, water temp, probably fuel pressure too. I don't know exactly what the Link can handle and do with those though. And if it's mainly just to cruise the streets, rather than mountain runs, you can probably skip most of the above if you've already got them in as gauges and warning lights.   PS, inb4 "sell it and buy a modern sportscar"
×
×
  • Create New...