Newbie questions! RB26 wont start after swap to Link

[Japtastic141]

Hi all, I may have something very obvious wrong but I can't see what! I'm coming from the car working with a PFC to the swap with a G4X where it won't.

I made the change to a 24-tooth AEM disc at the same time and believe I have the settings correct and the timing correct. All lines up when I use the timing light in the calibration mode now I have moved the offset to +10 there.

I have 600cc (vs 440cc stock) injectors so I changed the master trim to -20% but tried both ways and no difference.

I also have R35 GTR coils so I adjusted that as well but again, it makes no difference whether I leave them standard or adjusted to the no-start situation.

Any help much appreciated.

P.S Don't even know if the log I attached is correct, just shout if not.

Cheers

PC Datalog - 2024-02-16 10;32;29 am.llgx Test.pclx

[Laminar]

Are the plugs wet with fuel after cranking? If you open the throttle while cranking does it try to fire at all?

[Japtastic141]

Yes I believe so but will double check in a bit. I can definitely smell fuel after cranking so probably yes.

Can’t really hear it trying to fire, throttle open or not. If it is it’s the most minimal amount I’ve ever heard.

[Adamw]

Master is too small, I would expect it to be up around 15-20ms for 600cc injectors.  

It is also possible your timing is 360 out so you are firing on exhaust stroke rather than compression - although your current offset looks about normal for an AEM disc.  If adding fuel doesnt give any further signs of life then try the offset at -350

Everything else in the log suggests all the fundamentals are there and working.  

 

[Japtastic141]

Thanks Adam. I was discussing on another forum as well and you are right about the offset. -350 did the trick

I must have installed the AEM disc upside down.

For the R35 coilpacks, I have copied the dwell table from the 350Z. Presumably, that’s still correct?

Do I need to make any adjustments for my Denso 195500-1370 injectors in the dead time table? Realised that they are 550cc not 600cc.

I'm also running a Nismo FPR and an upgraded fuel pump. This is currently running at 3.5 bar at idle. I believe the standard RB setup is 2.5 bar at idle.

Also, what's the deal with the 12v value going up and not following the curve down?

[AbbeyMS]

https://www.platinumracingproducts.com/pages/platinum-racing-products-r35-dwell-settings  R35GTR Coil Dwell settings

Stock base fuel pressure on a GTR is 3.0 with no BOOST ID connected

The injector dead time curve should be smooth , where did you get your infomation from?

 

 

[Japtastic141]

Thanks for the link. Will check through that.

That is the standard one from the pre-loaded base map. Maybe an issue from Link on that one.

What values should I use there for my injectors?

[Adamw]

Those old RX7 injectors were prone to leaking about 20years ago when I used to play with them, so I hope they have improved with age.  Can you check their resistance, I vaguely remember them coming in both high and low-impedance versions but with the same part number.   Assuming this is a GTR? - does it still have the factory injector resistor in place?

[Japtastic141]

Haha! Didn't realise they were from an RX7. I've had them all out, ultrasonic cleaned them and tested the flow and leakage and appeared all good so I decided to stick with them for now. They are low impedance with the resistor still in place. Yes, RB26DETT.

I have 100's of questions while getting used to PC Link vs FC Edit/Co-Pilot and am finding lots of answers here and HPA but here are a couple I'm stuck on.

I've done around 50 miles of road tuning and some manual and mixture map adjustments to fueling.

1. I'm not sure of the best way to handle boost control. The first part is the physical aspect. I've still got my old boost controller in place at the moment but do have a MAC 3 port ready to put in. My only reason for not putting in the new 3 port was thinking that it would be another thing to learn on top of an already very steep learning curve and using a known entity to start with would be beneficial.

The second part is the software aspect and how to adjust this. Do I use the 4D Fuel Map, Open Loop AFR target overlay (and what AXIS' are the most common?) or some other way I've not come across yet?

2. I have a permanently installed Bosch/AEM AFR WB installed and the analog output configured in PC Link. Once I've got my tune a bit more refined, how good is Closed Loop Lambda control on the RB? Are the default values in the settings for CLL some generic values or refined to the RB? The settings seem fairly conservative with a cut-off at 80kpa MAP and 5000RPM. If these could be increased could I rely on CLL more for fueling corrections above these cut-offs or is that a bad idea?

Thanks!

[Adamw]

The base map is already set up as Alpha-N with MAP and lambda target multiplication.  There is also a 4D fuel table set up, but zeroed out.  Tune the entire main fuel table on the lowest boost you intend to run.  When the main fuel table is tuned, then increase boost to the maximum you wish to run do a pull and see how well lambda tracks the target.  If it follows target close enough then job is done, you can disable the 4D table.  If it has stock or near-stock turbos you will likely find it will start to drift rich at the top end when the turbines start to limit efficiency.  If this happens you can put negative values in the high boost/high RPM corner of the 4D fuel table to pull a little fuel out where it goes rich. 

Boost control is really up to you, the ECU gives you more control such as boost by gear, IAT or ECT compensation etc, but will definitely take some time to learn.

 

4 hours ago, Japtastic141 said:

I have a permanently installed Bosch/AEM AFR WB installed and the analog output configured in PC Link. Once I've got my tune a bit more refined, how good is Closed Loop Lambda control on the RB? Are the default values in the settings for CLL some generic values or refined to the RB? The settings seem fairly conservative with a cut-off at 80kpa MAP and 5000RPM. If these could be increased could I rely on CLL more for fueling corrections above these cut-offs or is that a bad idea?

Tune with closed loop off would be my general suggestion.  The values you see when you enable it are just default values, not specific to the RB.  I typically run CLL full time but that is with a CAN lambda which has more sensor validation than most as well as fail-safe considerations for CLL, I would have less confidence with a low-cost wideband controller, especially if it is connected via analog signal.  You could still do it, just be careful to only allow small negative or zero negative corrections at high boost.  

[Japtastic141]

Ok, in that case, I will wire up the wideband to CAN for more reliability. Any experience in how reliable the AEM/Bosch WB is? I know it is a low-cost option.

So are you saying you take out the RPM, TPS and MPA lockout limits and just let CLL have control of the whole map? Then presumably turn on long-term fuel trims?

[koracing]

The AEM X-Series widiebands with CAN have proven to be very reliable for me.  Have yet to have to even replace a sensor on any I've in stalled in the last 4-5 years.  CLL with long term trims can help dial in your fuel table if you make sure the LTT table matches break points on your fuel table (easiest way to start by exporting the fuel table, then importing it to the LTT table, and then reset the LTT table values to all zero).  if it is improving as you drive, then applying the LTT table Normally I would suggest not using closed loop on boost at all - or at least abovea bout 120kpa, and certainly limit it's ability to adjust to negative values in any boost.  

[Japtastic141]

Thanks, Kris. That's good to know. I'm yet to put the MAC 3 port in as I've got so much else to learn that doing that as well at the moment is going to overload me!

I know this means I may well have to tune it again but that's fine as all good experience.