Jump to content
SAU Community

Recommended Posts

Hey guys,

I've recently installed a greddy style front facing plenum, FMIC, 80mm throttle body and oil cooler. I started the car up and it idles normally... good start.

Unfortunately, when I gave it some throttle, the revs build then drop and build then drop. Not good. I'm getting fault code 55 "ALL OK". Could anyone shed some light on what I should look at to get this sorted?

On 03/11/2021 at 4:11 PM, GTSBoy said:

What does your ECU tell you that it is doing?

Please tell me that you're not trying to run this on a stock ECU.

Yeah I am running this on a stock ECU. The way I was looking at it is that the stock ECU would be able to cope with the difference in airflow being that everything else is stock.

Do you reckon this is the culprit?

The reason I wanted to know you weren't trying it on a stock ECU is that changing to a really big TB is something that requires that you have a good handle on the mechanical and electrical condition of all the other things that matter, like the idle control motor. If you're doing it on a stock ECU, like everyone else who has ever done that before and had troubles (which is a massive percentage of all such examples) then you're flying blind, because you don't even know if your idle control system was workin before and you sure as hell don't know now and unless you have a decent Consult device or Nistune in the ECU (which you would have already used to find out what was going on if you did) you have no way of looking inside to see what it is doing.

Whereas, if you had an aftermarket ECU, even if it was Nistune in the stocker, you would know whether everything was working or not because you would have put the effort into making it work when the ECU was set up. And you'd be able to look inside and see what was happenign with the idle control.

The fact that pulling the TPS steadied the idle means that the ECU is now no longer using timing to try to control the the idle speed, which suggests that the idle control valve is not properly functional. You've quite possibly also got a large vacuum leak somewhere, or maybe the large TB is not closed enough to give the IACV enough scope to slow the idle.

  • Like 1
On 03/11/2021 at 10:07 PM, GTSBoy said:

The reason I wanted to know you weren't trying it on a stock ECU is that changing to a really big TB is something that requires that you have a good handle on the mechanical and electrical condition of all the other things that matter, like the idle control motor. If you're doing it on a stock ECU, like everyone else who has ever done that before and had troubles (which is a massive percentage of all such examples) then you're flying blind, because you don't even know if your idle control system was workin before and you sure as hell don't know now and unless you have a decent Consult device or Nistune in the ECU (which you would have already used to find out what was going on if you did) you have no way of looking inside to see what it is doing.

Whereas, if you had an aftermarket ECU, even if it was Nistune in the stocker, you would know whether everything was working or not because you would have put the effort into making it work when the ECU was set up. And you'd be able to look inside and see what was happenign with the idle control.

The fact that pulling the TPS steadied the idle means that the ECU is now no longer using timing to try to control the the idle speed, which suggests that the idle control valve is not properly functional. You've quite possibly also got a large vacuum leak somewhere, or maybe the large TB is not closed enough to give the IACV enough scope to slow the idle.

Copy that mate! You are 100% correct. I ordered a Consult connector yesterday because I realised that I can't get very far if I don't have any way to query what the engine is doing.

Did you watch the video I posted? The idle was fine. I was getting issues when the throttle was open. Do you think that could have been due to the ECU doing a calc on fuel based on the volume of air expected through the stock throttle body using the TPS; and now that I have a bigger TB the calc would be off and result in running lean? I don't know if that is how it works but it was just the idea I had before disconnecting the TPS.

On 11/4/2021 at 6:07 AM, fried_bride said:

Did you watch the video I posted?

No. It won't load.

On 11/4/2021 at 6:07 AM, fried_bride said:

Do you think that could have been due to the ECU doing a calc on fuel based on the volume of air expected through the stock throttle body using the TPS; and now that I have a bigger TB the calc would be off and result in running lean?

No, the ECU doesn't give a stuff about the TB. The air flow meter is at the other end of the inlet tract, and that's where the air flow is measured.

If you're having trouble with the throttle open, it's starting to sound like the TPS isn't right.

Many issues there, some I can see:

  • Stock ECU
  • AFM & pod filter
  • Reversion from intake pipe
  • Stock BOV deleted & using a AFM

Easiest fix, throw the stock ECU and AFM into the bin, install a proper speed density ECU.

On 04/11/2021 at 9:01 AM, GTSBoy said:

No. It won't load.

No, the ECU doesn't give a stuff about the TB. The air flow meter is at the other end of the inlet tract, and that's where the air flow is measured.

If you're having trouble with the throttle open, it's starting to sound like the TPS isn't right.

Fair enough haha she was a beefy sized vid.

 

Thanks for the help mate!

On 04/11/2021 at 9:20 AM, Dose Pipe Sutututu said:

Many issues there, some I can see:

  • Stock ECU
  • AFM & pod filter
  • Reversion from intake pipe
  • Stock BOV deleted & using a AFM

Easiest fix, throw the stock ECU and AFM into the bin, install a proper speed density ECU.

Copy! Any suggestions on an ECU? Been looking at a Power FC or one of those Haltec Plug and Play bad boys, but this is my first time doing all this stuff so I am very unsure.

It's 2021 lol... please do not install a PowerFC, also you'll still need the AFM with the PowerFC and the way you've set everything up, a PowerFC will still give you you idle and stalling issues.

Just get a Haltech Platinum Pro Plug-in used if you can, great value and provides all the features you would need. If you have money and decide that one day you'll go tits out then get a better ECU that supports DBW, strain gauge input, etc.

  • Like 1
On 04/11/2021 at 9:59 AM, Dose Pipe Sutututu said:

It's 2021 lol... please do not install a PowerFC, also you'll still need the AFM with the PowerFC and the way you've set everything up, a PowerFC will still give you you idle and stalling issues.

Just get a Haltech Platinum Pro Plug-in used if you can, great value and provides all the features you would need. If you have money and decide that one day you'll go tits out then get a better ECU that supports DBW, strain gauge input, etc.

You're a legend mate. Thank you very much for the advice.

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

    • Back again. I returned to Japan in Jul/Aug to spend time with the car on my birthday and remind myself what all the sacrifice and compromise is for. It happened to line up with the monthly morning meet in Okutama, which I have been wanting to go to for a long time. It's a unique event at a unique spot with really rare, interesting, and quirky cars. It's where all the oldheads and OGs gather. The nighttime scene at DKF certainly has its place and should be experienced if you're into cars, but there's too much bad attention and negativity around it now. IMO the better time is Sunday morning at DKF or Okutama; it's more chill and relaxed. I'm glad I was finally able to go, but not sure it's worth the drive from all the way from Nagoya immediately the day before, unless I was already staying in Tokyo for the days right before the meet, because you have to wake up quite early to make it in time. Funnily enough though I didn't drive the car all that much this trip because it was just too damn hot. While there were zero issues and running temps were nominal and the A/C was strong, RBs already run crazy hot as it is. Sure, it took it all like a champ but something about driving these cars in the ridiculous heat/humidity bothers me and makes me feel like I'm asking too much of it. I'm just me being weird and treating the car like a living thing with feelings; I'm mechanically sympathetic to a fault. Instead I was mainly driving something else around - a KX4(silver) 2001 X-Trail GT, that I acquired in May. There's a few different flavors to choose from with Xs, but visually it's the Nissan version of the Honda CR-V. Mechanically it's a whole different story as this, being the top-trim GT, has an SR20VET mated to a four-speed auto and full-time AWD! It was a very affordable buy in exceptional condition inside and out, with very low mileage...only 48k kms. Most likely it was owned by an older person who kept it garaged and well-maintained, so I'm really happy with how it all worked out. It literally needs zero attention at the moment, albeit except for some minor visual touch-ups. I wanted something quirky, interesting, and practical and for sure it handily delivers on all three of those aspects. I was immediately able to utilize the cargo and passenger capacity to its full extent. It's a lot of fun to drive and is quite punchy through 1st and 2nd. It's very unassuming -in the twisty bits it's a lot more composed than one would think at a glance- and it'll be even better once I get better tires on it(yes, it's an SUV but still a little boat-y for my liking). So...now I have two golden-era Nissans in silver. One sports car and one that does everything else; the perfect two-car solution I think👍 The rest of the trip...I was able to turn my stressed brain off and enjoy it, although I didn't quite get to do as much as I thought. I did some interesting things, met some interesting people, and happened into some interesting situations however, that's all for another post though only if people really want to know. Project-wise, I went back to Mine's again to discuss more plans and am hoping to wrap that up real soon; keep watching this space if that interests you. Additionally, while working in the tormenting sweatbox that is the warehouse, I was able to organize most of the myriad of parts that my friend is storing for me along with the cars, and the 34 has a nice little spot carved out for it: And since it can get so stupid hot in there, that made it all the more easy -after I was standing there looking at the car and said 'f**k it'- to finally remove all the damn gauges that have mostly been an eyesore all this time. Huzzah. The heat basically makes the adhesive backing on the gauge mounts more pliable to work with, so it was far less stressful getting this done. I didn't fully clean it up or chase the wiring though; that will happen once I have the car in closer possession. Another major reason to remove all that stuff is to give people less reasons to get in my car and steal s**t while it's being exported/imported when/if the time comes, which leads us to my next point... ...and that is even though it's time in Japan is technically almost up since it's a November car and the X would be coming in March, I'm still not entirely sure where my life and career is headed; I don't really know what the future looks like and where I'm going to end up. I feel there's a great deal of uncertainty with me and as a result of that, it feels like I'm at a crossroads moreso now than any point in my life thus far and there are some choices I need to make. Yes, I've had some years to consider things and prepare myself, however too much has happened in that time to maintain confidence and everything feels so up in the air; tenuous one might say. Simply put, there's just too much nonsense going on right now from multiple vectors. Admittedly, I'm struggling to stay in the game and keep my eyes on the prize. So much so in fact, that very recently I came the closest I ever have before to calling it quits outright; selling everything and moving on and not looking back. The astute among you will pick up on key subtext within this paragraph. In the meantime I've still managed to slowly acquire some final bits for the car, but it feels nice knowing there's not much left to get and I'm almost across that finish line; I have almost everything I'll ever want for my interpretation and expression on what it is I think an R34 should be. 'til later.
    • Thanks for that, hadn’t used my brain enough to think about that. 
    • Also playing with fire if they start to flow more air down low than what the stock twins can. It's not even up top you need to worry, it can be at 3000rpm and part throttle and it's getting way more flow than it should.
    • Any G40/1000 or G40/1250 results out there?  
    • You still want a proper tune on the stock ECU though. Stock tune + stock ECU with GT-SS/-9s is probably playing with fire if you're running more than stock airflow/power.
×
×
  • Create New...