Nistune Forums

Hi all,
I've been having a few issues at cold start (UK) since my car was mapped.
I had everything done at once so is difficult to narrow down the root cause
R33 type 1 RB25DET fitted with z32 ecu+type 2 board / z32 MAF / jecs 550cc
car starts fine but as soon as I use light throttle it splutters .. higher revs will overcome the issue until it warms up.
AFRs at cold start are around 10 - 11 ... so I'm guessing this is rich for a cold start.

one thing i wanted to check was the warmup timing timing table ... reading other posts people are talking about running 7 - 12 degrees across the table, whereas the z32_for_RB25 bin files (and mine) show loads more timing (attached) .. would this cause the bogging down or spluttering?

thanks,
Andy

vincentav8 wrote:Hi all,
I've been having a few issues at cold start (UK) since my car was mapped.
I had everything done at once so is difficult to narrow down the root cause
R33 type 1 RB25DET fitted with z32 ecu+type 2 board / z32 MAF / jecs 550cc
car starts fine but as soon as I use light throttle it splutters .. higher revs will overcome the issue until it warms up.
AFRs at cold start are around 10 - 11 ... so I'm guessing this is rich for a cold start.

one thing i wanted to check was the warmup timing timing table ... reading other posts people are talking about running 7 - 12 degrees across the table, whereas the z32_for_RB25 bin files (and mine) show loads more timing (attached) .. would this cause the bogging down or spluttering?

thanks,
Andy

That are the standart values on the Rb25det with Z32 ecu. I wouldn't be worry about the timing, i think your problem is more fuel related. You could try to reduce the values in the "Warm enrich" and "Cold enrich" tables. I'm not sure when which table is applied, but both has the same values from nissan, so adjust them together to the same values.

*Matt edit . Standard value are 15-18 BDTC in our ROM file

Two issues:
1. Your idle/decl table in RAW mode should have +128 added to the current values. Ie:
143 143 143 143 143 143 143 143 143 143 148 148 148 148 148 148

Viewed in filtered mode as:
15 15 15 15 15 15 15 15 15 15 20 20 20 20 20 20

(Right click to change the Raw/filtered view type)
So currently your timing would be reported as 0. Strange since I had the same issue with a workshop today

2. With regards to timing on Z32 RB25 setups, a customer recently contacted me via email and let me know that their R33 timing values at cold start were around 25 deg BDTC at idle and gradually reduced to 15 deg BDTC

Z32 ECUs appear to be 35 deg BDTC instead. Some further digging found the 4 x cold idle timing tables were in fact 32 cells wide (not 16 cells as per 0.11 version). So I've increased the cell count in 0.11.1 and subsequently you can reduce these 4 x cold idle tables by 10 degrees BDTC to assist the TPS off idle transition

Hi Matt and A&M,
Thanks of for the info. From what I had read I thought that the cold start and warm start enrichment tables were only used to start the car and stopped having an influence as soon as the engine is running? But I will have a play and see if the AFRs look any better with lower values in these tables.

Regarding the timing tables I'm a bit confused now

I thouight the Warm up timing table in the z32_for_rb25_41p03_mt_v2.bin file shows the same as my screenshot ... unless I've somehow overwritten my copy? I'll download again this evening and see if anything changes.

I need to check my cold/idle timing tables as well, and will download the latest software release to check this.
I'll report back when I've been able to have a proper look at the tables.
many thanks,
Andy

There are two views with warmup timing. Raw (+128 to filtered values) and filtered

Your current table is missing the +128 flag so it appears okay but should be the numbers I posted. Either copy this map again from the Z32 for RB25 map in the ROM pack... or type in the numbers I've posted here to get that back on track

Cold/warm enrichment is used upto about 85degC
After start enrich is the one which is only used for a small time after crank

Hi Matt,
Thanks for the clarification on the cold and warm enrichment ... I'll take a look at these.
But ... are we talking about the same 'warm up timing' tables?
Your screen print shows idle / decel tiiming ... the one I posted was warmup timing?
I have just downloaded the ROM pack again and it shows the following in Raw and Filtered whereas if I open the idle / decel timing I get the same as you.
I just didn't want to start changing values in the wrong table

many thanks, Andy

Sorry for the confusion... I got the wrong table there. That was idle/decel table. Warmup table is fine

No worries, thanks for clarifying.

So back to the cold / warm enrichment tables ... I'll try leaning these out a bit, and will also have a look at the 4 cold start timing tables that are now 32 cell tables.

I'll let you know how I get on.

thanks again

Okay, well that we spike now over the same tabel Does anybody know for what this "Warmup timing coditional" table is?
there are confusing values in the table

I did a great deal of investigation on RB25 to Z32 idle tables
and as far as I am concerned the parameters between these 2 ECUs are not directly interchangeable.


The Z32 seems to use very different code/strategies to maintain the engine idling.

For example the Z32 tables:
Idle Stabilization Min
Idle Stabilization Max
Idle Stabilization Advance

Are all ZERO on Z32 (so possibly unused), however on RB25 these are set.

On RB25 the ECU seems to have separate tables for the amount of ignition to be varied.
On Z32 it is obviously working differently.

I use the Z32 values for idle timing except for the After Start Table.

Matt wrote:Two issues:
1. Your idle/decl table in RAW mode should have +128 added to the current values. Ie:
143 143 143 143 143 143 143 143 143 143 148 148 148 148 148 148

Viewed in filtered mode as:
15 15 15 15 15 15 15 15 15 15 20 20 20 20 20 20

(Right click to change the Raw/filtered view type)
So currently your timing would be reported as 0. Strange since I had the same issue with a workshop today

2. With regards to timing on Z32 RB25 setups, a customer recently contacted me via email and let me know that their R33 timing values at cold start were around 25 deg BDTC at idle and gradually reduced to 15 deg BDTC

Z32 ECUs appear to be 35 deg BDTC instead. Some further digging found the 4 x cold idle timing tables were in fact 32 cells wide (not 16 cells as per 0.11 version). So I've increased the cell count in 0.11.1 and subsequently you can reduce these 4 x cold idle tables by 10 degrees BDTC to assist the TPS off idle transition

Okay, well that we spike now over the same tabel Does anybody know for what this "Warmup timing coditional" table is?

This timing table is conditionally used when the ECU is within the bounds of the 'warmup timing' parameters in the 'Timing control section'. The main ones are temp min-max ranges where the table is used and under TP/RPM conditions