Jump to content
SAU Community

Rb30Det Refusing To Run Smoothly!

Nostalgic R31
 Share

Recommended Posts

Nostalgic R31 Rookie

Nostalgic R31

Posted
Posted

Hey guys

I've finally dropped my rb30det into my r31.

Engine is a bog stock rb30 bottom end with a recon rb25 head with vct welded up.

Engine was dropped into the car with a to4z, 1600cc injectors, Freddy plenum and Nistjne running E85.

Now the car starts and runs. Started almost straight away when I fired it up and idled there.

It idles very lumpy and rough. I put this down to the old tune on the nistune

I have since taken the car to the tuner, who put a base tune on it but couldn't go any further because it revs very rough. Like a constant misfire.

So. I've changed the throttle body, replaced injectors, changed from stock coils to ls2 coils, changed afm (z32 to r35) made a new coil pack harness and made a new injector harness to try and fix the issue but no luck.

Now I'm here left scratching my head wondering why this thing just doesn't want to run properly?

It has fuel on all 6, and it also has spark.

Makes no sense as to why it's misfiring?

The engine wants to run, but just seems like one cylinder doesn't want to play. It starts with a little help of the accelerator, then idles away very rough, then if you rev it it'll roughly rev up. But it doesn't hesitate or cough or splutter. Just very rough.

I'm hoping someone out there with more knowledge then my would be able to help me with this very frustrating issue

Cheers guys

Link to comment
https://www.sau.com.au/forums/topic/445232-rb30det-refusing-to-run-smoothly/
Share on other sites
Ben C34 Grand Master

Ben C34

Posted
Posted

Have you narrowed it to a cylinder by unplugging injectors or looking at spark plugs?

If it's a random occurrence I would be checking cam timing.

You will have to adjust the dwell to get the most out of those coils. On stock dwell mine missed over approx 14psi with ls coils. Won't cause amiss otherwise though.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Key to solving problems is to change one thing at a time. Is the ECU set up right for the new injectors, coils? Should have kept the VCT. Have you done a compression test and/or leakdown test? Have you tried disconnecting one cylinder at a time to see if you can isolate the problem to one cylinder? Double checked the valve timing?

Nostalgic R31 Rookie

Nostalgic R31

Posted
  • Author
Posted

I have unplugged the coils and injectors while the car is running. Cylinder one make no difference when unplugged, but all the rest do.

Took out the coil and injector from cylinder one and swapped them to cylinder 2. Still missing cylinder one.

Now here's where it gets weird.

Take injector out of rail and then manually turn cas by hand, and she fires. Take out coil and spin cas, it also fires.

Test all plugs with multimeter and it has all the right values.

So, why no cylinder one?

Compression test is super low. 100psi exact on all 6

Nostalgic R31 Rookie

Nostalgic R31

Posted
  • Author
Posted

I have swapped over to another set if injectors, so I hope I'm not that unlucky of having 2 bad injectors haha

It is running insanely rich.

You can see fuel spitting out the exhaust.

No, I don't have access to a leak down tester.

Cheers Ben, I'll double check the timing and make sure it's all good

r33_racer Grand Master

r33_racer

Posted
Posted

Its possible you have a dud plug. Have you tried just swapping a plug to another cylinder or putting a new plug in number 1?

I have seen plugs spark when tested outside engine but don't fire properly when installed. Considering a plug is worth about 4-5 bucks its an easy and cheap test.

Nostalgic R31 Rookie

Nostalgic R31

Posted
  • Author
Posted

I'm in perth. The only place I have called who said they will touch it is PZP in Wangara.

Every other place pretty much said "Z32 ecu on a RB30 with E85? Come back with a Power FC"

I have gone through 3 sets of plugs hoping that was the issue. But made no difference. I've also gapped the plugs at different levels to see if that helped.

I tried a noid light and spark tester to see if the coil and injector were firing together. Now I can obviously only test one cylinder at a time but it looked like the injector and coil are firing when they should.

Double checked mechanical timing. It's spot on.

Tried adjusting the cas to see if ignition timing was off, and it made no difference.

I performed countless compression tests, while the readings are low, they are all within 5 psi of each other.

The injectors are 1600cc top feeds.

And I haven't tried new clips, but the noid light shows it working, and also if I put a spare injector on the clip I can feel it clicking in my hand when it should be firing.

I have narrowed it down to cylinder 1 and 6 that are not working. I can take the plugs off both this injecotors while running and it makes no difference.

This really has me confused

Cheers guys for the help so far though!

Nostalgic R31 Rookie

Nostalgic R31

Posted
  • Author
Posted

I'm in perth. The only place I have called who said they will touch it is PZP in Wangara.

Every other place pretty much said "Z32 ecu on a RB30 with E85? Come back with a Power FC"

I have gone through 3 sets of plugs hoping that was the issue. But made no difference. I've also gapped the plugs at different levels to see if that helped.

I tried a noid light and spark tester to see if the coil and injector were firing together. Now I can obviously only test one cylinder at a time but it looked like the injector and coil are firing when they should.

Double checked mechanical timing. It's spot on.

Tried adjusting the cas to see if ignition timing was off, and it made no difference.

I performed countless compression tests, while the readings are low, they are all within 5 psi of each other.

The injectors are 1600cc top feeds.

And I haven't tried new clips, but the noid light shows it working, and also if I put a spare injector on the clip I can feel it clicking in my hand when it should be firing.

I have narrowed it down to cylinder 1 and 6 that are not working. I can take the plugs off both this injecotors while running and it makes no difference.

This really has me confused

Cheers guys for the help so far though!

Nostalgic R31 Rookie

Nostalgic R31

Posted
  • Author
Posted

It has been tuned for the injectors, but I did the coil conversion afterwards, as I thought the old coils might of been the issue.

I ran it today on a stock ecu to see what would happen and it ran exactly the same too

Might re do the wiring for the 3rd time and see if that helps

Badgaz Experienced

Badgaz

Posted
Posted (edited)

just a thought...but have you check your tps is showing between 0.4 and 0.5 volts when throttle is closed i.e at idle? what idle air control are you running on it? factory AAC? was the nistune actually setup for the injectors? - edit realized this has already been asked by kiwirs4t

Edited by Badgaz

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

    • oHBoy.
      Starter motor replacment teeth count.

      By oHBoy. · Posted

      I had 3 counts over the last couple of weeks once where i got stranded at a jdm paint yard booking in some work. 2nd time was moving the car into the drive way for the inspection and the 3rd was during the inspection for the co2 leak test. Fix: 1st, car off for a hour and half disconnected battery 10mins 4th try car started 2nd, 5th try started 3rd, countless time starting disconnected battery dude was under the hood listening to the starting sequence fuel pump ect.   
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      This. As for your options - I suggest remote mounting the Nissan sensor further away on a length of steel tube. That tube to have a loop in it to handle vibration, etc etc. You will need to either put a tee and a bleed fitting near the sensor, or crack the fitting at the sensor to bleed it full of oil when you first set it up, otherwise you won't get the line filled. But this is a small problem. Just needs enough access to get it done.
    • suko
      J50 clock date suddenly reset to January 1

      By suko · Posted

      The time is always correct. Only the date is wrong. It currently thinks it is January 19. Tomorrow it will say it is January 20. The date and time are ( should be ! ) retrieved from the GPS navigation system.
    • MBS206
      Mistakes were made, my R34 Story

      By MBS206 · Posted

      Buy yourself a set of easy outs. See if they will get a good bite in and unthread it.   Very very lucky the whole sender didn't let go while on the track and cost you a motor!
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      Well GTSBoy, prepare yourself further. I did a track day with 1/2 a day prep on Friday, inpromptu. The good news is that I got home, and didn't drive the car into a wall. Everything seemed mostly okay. The car was even a little faster than it was last time. I also got to get some good datalog data too. I also noticed a tiny bit of knock which was (luckily?) recorded. All I know is the knock sensors got recalibrated.... and are notorious for false knock. So I don't know if they are too sensitive, not sensitive enough... or some other third option. But I reduced timing anyway. It wasn't every pull through the session either. Think along the lines of -1 degree of timing for say, three instances while at the top of 4th in a 20 minute all-hot-lap session. Unfortunately at the end of session 2... I noticed a little oil. I borrowed some jack stands and a jack and took a look under there, but as is often the case, messing around with it kinda half cleaned it up, it was not conclusive where it was coming from. I decided to give it another go and see how it was. The amount of oil was maybe one/two small drops. I did another 20 minute session and car went well, and I was just starting to get into it and not be terrified of driving on track. I pulled over and checked in the pits and saw this: This is where I called it, packed up and went home as I live ~20 min from the track with a VERY VERY CLOSE EYE on Oil Pressure on the way home. The volume wasn't much but you never know. I checked it today when I had my own space/tools/time to find out what was going on, wanted to clean it up, run the car and see if any of the fittings from around the oil filter were causing it. I have like.. 5 fittings there, so I suspected one was (hopefully?) the culprit. It became immediately apparent as soon as I looked around more closely. 795d266d-a034-4b8c-89c9-d83860f5d00a.mp4       This is the R34 GTT oil sender connected via an adapter to an oil cooler block I have installed which runs AN lines to my cooler (and back). There's also an oil temp sensor on top.  Just after that video, I attempted to unthread the sensor to see if it's loose/worn and it disintegrated in my hand. So yes. I am glad I noticed that oil because it would appear that complete and utter catastrophic engine failure was about 1 second of engine runtime away. I did try to drill the fitting out, and only succeeded in drilling the middle hole much larger and now there's a... smooth hole in there with what looks like a damn sleeve still incredibly tight in there. Not really sure how to proceed from here. My options: 1) Find someone who can remove the stuck fitting, and use a steel adapter so it won't fatigue? (Female BSPT for the R34 sender to 1/8NPT male - HARD to find). IF it isn't possible to remove - Buy a new block ($320) and have someone tap a new 1/8NPT in the top of it ($????) and hope the steel adapter works better. 2) Buy a new block and give up on the OEM pressure sender for the dash entirely, and use the supplied 1/8 NPT for the oil temp sender. Having the oil pressure read 0 in the dash with the warning lamp will give me a lot of anxiety driving around. I do have the actual GM sensor/sender working, but it needs OBD2 as a gauge. If I'm datalogging I don't actually have a readout of what the gauge is currently displaying. 3) Other? Find a new location for the OEM sender? Though I don't know of anywhere that will work. I also don't know if a steel adapter is actually functionally smart here. It's clearly leveraged itself through vibration of the motor and snapped in half. This doesn't seem like a setup a smart person would replicate given the weight of the OEM sender. Still pretty happy being lucky for once and seeing this at the absolute last moment before bye bye motor in a big way, even if an adapter is apparently 6 weeks+ delivery and I have no way to free the current stuck/potentially destroyed threads in the current oil block.
×
×
  • Create New...