Hello,
I decided to try the V3 firmware out today. I ran through the settings and brought across long-running fuel and ignition maps from V2.
However, around 2000-2200 rpm the car breaks up and has an extremely pronounced loss of torque, almost as if a rev limiter is active.
I downgraded back to V2 and a known good map, but the fault now persists.
I have verified coils, injectors, fuel pump, base timing etc.
On the downgrade to V2 I noticed that things such as my input/output names had been transferred back from the V3 profile in a buggy state.
The car reads lean (lambda 1.5) in this range but runs perfect above and below.
Any ideas for first troubleshooting?
k1.emub3 (59.4 KB)
kmrs 11.0.12 turbo.emub (145.9 KB)
If the problem occurs on v2 with the working before base map, you need to look for some hardware failure tonfind the reason.
Eg. Low fuel pressure, low battery voltage, etc.
Hi Jadz,
I understand your line of thinking, however could I politely request a second look.
This is not some thrown together build- I have well over 10,000 km of reliable road and track testing on it.
I’ve been through the obvious things- fuel, coils, sparkplugs, injectors etc.
I haven’t found anything, or been able to reproduce this fault at any other rpm point. I am not sure my downgrade to V2 was clean either- see photo 1, the INPUT switches in V2 have carried names back from the OUTPUTS in V3.
The fault RPM range is highly specific and consistent- 2000 to 2200 RPM or so. My first thought was the overrun feature introduced in V3, as 2000 and 2200 are default control points for this. However, deactivating overrun does nothing to help.
This fault coincided perfectly with the change to V3.
I would really appreciate it if you could assist with a bit more of a deep dive on this
Thank you
attaching current log files would help. Without them, anyone looking for problems will have a much harder time finding any faults or configuration issues.
20240504_2042.csv (376.7 KB)
why the forum doesn’t allow uploads of native logs i am unsure
Try to upgrade to V3 and set all parameters by hand - no copy or uploading from V2 project.
Now you should be able to add emublog files.
So please add here your black v2 base map and log with the problem.
I will take a look.
When you downgrade from v3 to v2 the whole ecu is reseted.
Try the follow:
Select from menu restore to default.
And then load base map you sure it worked before.
I think I have found the cause, I will update tomorrow when I’ve had a chance to retest from cold. Thank you!
Restoring to default and reloading the base map fixed the broken tag names
I think I may have to suck eggs on this one, but I think this was mechanical. I verified everything- fuel pressure, spark, base timing, etc. Swapped in new coils, new plugs, tested fuel pressure under load, checked compression, everything good.
Then I remembered last week I swapped the fuel line from a rubber hose to a PTFE/AN hose of larger diameter. Surely not this.
Never thought it could be this, but I swapped it back just to try.
Problem gone.
Checked the hose for blockages, cleaned it and reinstalled.
Problem came back.
I think the larger, stiffer hose was amplifying a fuel pulse issue (1200 cc injector on OEM dead head setup). Never would have believed it could cause an impact like this.
Since I’ve found numerous people with untunable lean spots in similar rpm ranges. Most seem related to upgrading injector size or removing OEM dampers (mine had no OEM damper). Seems common in 350z’s, LS’s etc.
I’ve ordered the rest of the parts to upgrade to a return style FPR, and have ordered an R35 fuel pulse damper to fit.
Thanks for taking a look at it!
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Thank you for information. It is very interresting.
