Did you ever had this srange thing when car fixed itself? A lot of stuff happened recently and if I was keeping up with this journal, it could probably be a couple of pages of self-contradictory posts.
So, here you'll only get end result as it is now. Although I'm not sure that there will not be any new findings that will completely change my perception of stuff happening.
So… I was trying to tune the car and it all was nice except when I hit throttle fast to WOT it had wild misfires and was looking kind of flooded (to me). First AFRs were going down while car was loosing all the power but slowly developing some boost. At the same time rpms were at the same level or even slightly decreasing and AFRs jumped to 15-16 which I considered being due to misfiring…Since my ESL ECU has quite a limited number of tables available compared to full standalone, after a post on UK forum where most of the users of this ECU are and quick chat with pro guy who tuned my other car on this ECU few years ago, I came to the conclusion that those 850cc injectors are just too big for this ECU to handle without being able to tune tip-in throttle, dead times etc.
I managed to revive my old 440s… one of them appeared to be stuck even after cleaning so I had do some extra DIY efforts to get it working:
After confirming that all injectors are working I installed them and for some time it seemed that everything was fine, problems solved…
But wait, there's more! Working further on new fuel map with smaller injectors I kind of found the limit where I couldn't get more fuel on higher loads, so I finally decided to finish long overdue stuff with some electrical gremlins and extra sensors for datalogging.
I installed and wired to datalogger fuel pressure and brake pressure sensors.
Remember that stuff I wrote that VSS square wave was wrong? Don't know where I got that, both ECUs need 5v signal, but!!.... before I found that I made small transistor circuit that provided that 12v square wave to ECU and guess what? It didn't start with it.. investigating further I found out that it's not 5v square wave that ECU needs, vss2 signal it's rather a switched ground that pulls down 5v signal that comes from ECU. Figuring that out I checked dash, confirmed that built in VSS does just that and returned all my custom wiring back to starting position. and it worked! Miracle. Also, that one ground wire from instrument cluster that I had to disconnect from harness to get car running which resulted in temp gauge not working - I checked all respective diagrams, confirmed that it has to be there, plugged it in and everything just works! What was the problem before - who knows…
Anyway. I took car for test drive and what I saw was this:
Basically, my fuel pump failed to provide any pressure above 2.5 bar in fuel rail during moderate and high loads...
Lots of swearing and one new wallbro fuel pump later:
I know, I should have done this from the very start… that was really stupid… my bad.
So yesterday I was thinking that my fueling issue was due to bad fuel pump from the very start, so I swapped back 850cc injectors and it seems fine. Fuel map is still rough, but the main issue I had is not there anymore, so I'm keeping 850s and working on further development of fuel map for this setup.
Together with this finding I kind of noticed that my intercooler is not working at all. IAT increases from ambient to 50..60 deg C (around 140 F) during one 3rd or 4th gear pull… and that even during night runs, can't imagine what it will be on a hot day. That means pulling like 6 deg of timing, so not good… I believe that's because I had to remove intercooler shroud from the scoop on the bonnet because I installed larger ver4 intercooler and it interfered. Now I'm working on custom solution to seal airflow from scoop to the intercooler. I'll post the results when I have something.