Jump to content
SAU Community

Neo Fuel Problem

JonnoHR31

By JonnoHR31,
in Engines & Forced Induction

 Share

Recommended Posts

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

Just finished putting an auto er34 rb25det into a manual hr31, wired it up and got it running yesterday. It started straight away and idles like a dream, except the ecu isn't putting in any extra fuel when pumping the throttle, making it UN-drivable.

I've been over the TPS wiring several times, its got power and at the ECU plug the signal wire reads .45v when closed and 4.0-4.1v at WOT so the ECU is getting the TPS signal and it's working as it should. As far as i know the TPS signal is the only thing the ECU uses for throttle pump injection so this has me stumped. Does anyone have any ideas why this wouldn't be working and how to fix it? Possibly something I've missed in the wiring? Or is there something else than can cause the same symptoms (stabbing the throttle causes revs to drop until the ECU picks up the extra flow via the AFM) that I'm missing?

Link to comment
https://www.sau.com.au/forums/topic/406040-neo-fuel-problem/
Share on other sites
GTSBoy Grand Master

GTSBoy

Posted
Posted

You need to get a consult connection going so you can see what's going on.

You're also going to need to Nistune it if you want to be able to get around the lack of traction control and ABS that the ECU expects to see. Otherwise it will throw codes about the TCS/ABS comms and the TCS throttle position sensor.

JonnoHR31 Grand Master

JonnoHR31

Posted
  • Author
Posted

Consult isn't really possible at the moment unless I can find someone local with one, might have a scope around the WA section.

There was always going to be error codes but I was under the impression they wouldn't affect the actual running of the motor? I've taken it for a test drive and apart from this throttle hesitation it drives perfectly and doesn't have any cuts under full boost or anything.

GTSBoy Grand Master

GTSBoy

Posted
Posted

Is it all still connected? If the ECU can't see the TCS TPS it'll have a fit.

The ECU still chucks a wobbly even if it is connected - if there is no TCS computer present to make the throttle do the close-open dance when the ignition is switched on. That's one of the error codes that comes up. Nistune can mask it.

And this stuff can still cause hassles even if you get past all these little annoyances. The Nistune blokes worked out that if you do not have the TCS stuff working, when you up the boost/flow and get up to a reasonably high power level, then the ECU starts pulling shenanigans that feels like a rev/boost limit, and can't be tuned out. It is possible that Stagea ECU images do not have that problem (as they do not use TCS).

GTSBoy Grand Master

GTSBoy

Posted
Posted

Got it sorted, had the ECU boost sensor hooked up to the manifold, moved it to the intake and now it's running fine. Weird.....

That'll do it. I just checked my engine. That sensor is connected to the crossover pipe immediately adjacent to the BOV. I guess it is not supposed to see vacuum.

Hanaldo Grand Master

Hanaldo

Posted
Posted

The ECU still chucks a wobbly even if it is connected - if there is no TCS computer present to make the throttle do the close-open dance when the ignition is switched on. That's one of the error codes that comes up. Nistune can mask it.

And this stuff can still cause hassles even if you get past all these little annoyances. The Nistune blokes worked out that if you do not have the TCS stuff working, when you up the boost/flow and get up to a reasonably high power level, then the ECU starts pulling shenanigans that feels like a rev/boost limit, and can't be tuned out. It is possible that Stagea ECU images do not have that problem (as they do not use TCS).

Spot on. It's very annoying :glare:

DVS JEZ Grand Master

DVS JEZ

Posted
Posted

One of the wires was broken but it didn't make any difference.

Got it sorted, had the ECU boost sensor hooked up to the manifold, moved it to the intake and now it's running fine. Weird.....

Can u Please explain this a little more?

Had a 34 come in that had the same symptoms as urs after another mechanic did a headgasket. I had to disconnect the boost sensor to stop it trying to stall on takeoff. Such a simple little thing

JonnoHR31 Grand Master

JonnoHR31

Posted
  • Author
Posted

It seams to not like seeing vacuum, so just make sure it's hooked up somewhere before the T/B and it should be fine.

Thanks for the suggestions everyone.

Hi Jonno, i know its off topic but why did you get rid of your RB30DET and put a AUTO RB25DET neo into your HR31?

Sold the car to my younger brother, put a stocker neo (it's now manual) in for him and I'm selling my engine seperately along with a lot of other stuff.

StevenCJR31 Veteran

StevenCJR31

Posted
Posted

It seams to not like seeing vacuum, so just make sure it's hooked up somewhere before the T/B and it should be fine.

Thanks for the suggestions everyone.

Sold the car to my younger brother, put a stocker neo (it's now manual) in for him and I'm selling my engine seperately along with a lot of other stuff.

ah cool . . . are you using the auto ECU that you got with the motor? could be causing issues if you are?

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

    • hoodedreeper
      Chris' Toyota Mark ii JZX110

      By hoodedreeper · Posted

      Initially I thought having a pair of Recaro seats would be a big bonus, it turns out these do get a little uncomfortable on long journeys (my fault, not the seat). I had a look through the GSM Performance website at reclining seats and booked an appointment to visit their show room. I got the Recaro Sportster CS for the R34 from here, was very happy with the service received so of course a re-visit was in order. Unfortunately the two Corbeau seats I had chosen aren't on display but they had 4 other options available. Two seats dug into my back, one dug into my legs and the other was perfect. I also found out that Recaro seats use a larger bolt pattern so some adaption was required. Luckily GSM offer some universal adaptors that should solve this problem. I searched the interwebs for price comparisons and Corbeau themselves were the cheapest at £300 cheaper (for the pair). I asked GSM if they could price match, unfortunately they couldn't. I later received an email saying Corbeau would honour them the same discount, but the purchase was already made. I did however order the brackets from GSM, both arrived on the same day. I started with the passenger side seat, knowing this was going to be a little trial and error. There are 3 mounting holes at the front and 2 at the rear on these JURAN Racing seat rails.  With the adaptor brackets mounted, the allen cap bolts started to push into the seat, NOT GOOD!  The rear mounting holes lined up but there were issues at the front. The holes were 1/2 hole out, so the brackets got a tickle with the drill to modify the holes. The supplied bolts weren't going to be long enough and a spacer was needed to stop the adaptor bars from bending. A local fasteners company supplied be with some nylon spacers and longer bolts (M8x30, although these will be replaced with 35mm long shortly) A before and after I pre-drilled the front bracket before making a start on the driver's seat to save some time. And in no time at all that was in the car too. The all black seats have transformed the interior and these are MUCH more comfortable. The only downside with the new Corbeau seats is I sit a little higher, but I'll happily accept that over discomfort. The Youtube video can be found here: https://www.youtube.com/watch?v=wPyttKPktXA
    • oHBoy.
      2001 R34DE

      By oHBoy. · Posted

      All 3 I guess. The car came with the JASI Aero 4 door Type R Full Kit unpainted so this was one thing at the top of my list to complete then I noticed there were body panels parts for this kit so i picked them up along with some black mesh to fill in the front bumper and front side air vents. car is at a paint and body shop atm completing this work. Next I will be addressing the internal bells and whistles, great summer project I can do with the kids.  full interior removal - ,boys car sound deadening - pads and spray ,boys stereo, sound, lighting - Big 3, GTT or bigger alternator ,kids head lining - dye black add star lighting mod ,daughter. That's it for the next 5-6 months. I have some motor maintenance  work i have to plan out. oil filter relocation, gaskets, mounts. beyond that, mind is starting to turn over if i can use a DET intake plenum, block off turbo ports & pipe in a air intake.      
    • oHBoy.
      Starter motor replacment teeth count.

      By oHBoy. · Posted

      roller coaster of a ride. Alarm system was removed & main harness was repaired where possible. still no fix just random successful starts. moved on to the replacing the ignition switch and relay. well all this troubleshooting & repair has been going on, the car is at a paint and body shop being pushed around. Ive been going down there on odd days after work to get it sorted.     
    • fatz
      Beers and skylines Fatz style

      By fatz · Posted

      5th November if you want to come out for a spin wakfield
    • jtha7
      Strange issue RB25DET wont start

      By jtha7 · Posted

      PROBLEM WAS BROKEN COOLANT SENSOR!!! Replaced with a new one and its running mint.
×
×
  • Create New...