Hi guys,
I'm really struggling with my M50 ethanol build.
Main issue is that the engine wont start the first time even at higher temperatures.
I tried a lot of settings for weeks in order to achieve an acceptable cold start performance. Nevertheless the best I could achieve is a setting, where I need to crank for more than 10 seconds before engine starts running. Firstly, I thought is was related to low air temperatures (below 15°C) however the issue exists also at higher temperatures (more than 25°C) as we had the last weeks.
If the engine decided to idle finally, I can switch off the engine an re-start without any issues. (Engine starts normal)
I added my cranking table and my fuel table… maybe someone has an idea what could be wrong.
cranking.JPGfuel-table.JPG
I'm running a MS2 on a 2,8l M50 engine with 120lbs injectors.
Thanks
Torsten
Try simply turning on the key to the run position (do not start the engine) and leaving it there for a few seconds, then shutting it off and doing this again to see if this improves the starting performance. Once you've cycled it once or twice, then attempt to start it. It is possible that your fuel system is not maintaining any residual pressure and this on/off key actuation before attempting to start the engine will raise pressure to a normal level (if this is your problem).
Most likely need to mess with the cranking table some more. Make sure the setting for cranking rpm is higher than your actual rpm when cranking. The symptom you describe sounds like it does not have enough fuel but your settings look really really high. Do you have a fuel pressure gauge?
Also the air temp is not a problem. E85 will start just fine at -30 C with the correct settings. I’ve tried.
Thanks guys for your reply.
Fuel pressure gauge is installed and shows 43psi directly after go into run position. So I assume no issues with the fuel system.
@someguy2800: I understood the cranking table as an percentage increase (over 100%) or decrease (below 100%) of the actual values in the fuel-table while cranking. Is that correct?
The last time I had this issue with a car, it was the actual injectors bleeding off fuel pressure when the car sat. I looked at EVERYthing else beforehand because they were brand new and I had them cleaned and flow tested. Went through 14 crank table revisions, new FPR, LPFP, etc, back to more maps. Replaced the injectors on a whim and boom, cold start perfect again.
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Is that 43 psi with it running and at idle with the vacuum line connected to the FPR?
I know you are on a stand-alone but the stock fuel system pressure should be 52 psi when you turn the key to the on position without starting the engine. The off and back on trick that Jaker suggested should get you to 52 psi if the system is functioning and adjusted correctly.
43psi at idle - sorry.
I dont know… I tried the whole afternoon "on-off-on-off-idle-off-on...…" I even missed the first half of the Germany soccer game (okay, it wasnt worth seeing and we lost - but thius is another story).
Finally I can say, that I didn't find a better setup - I just recognized that I have heavy hot start issues if water temp is above 95°C... Engine starts barley, only with 1 or 2 Cylinders and dies after a few seconds… after starting maybe ten times, engine starts again on 5 Cylinders and after some revs above 3000rpm you can feel that Cylinders running again.
Anyway… not a good day for tuning… maybe it is better to remove all the Ethanol again and start tuning on 100% gas. However I dont know whether I can achieve a smooth idle with such big high-resistance injectors… I assume they are already borderline even with 30% more duty cycle on E85. :-/
post your config/and logs.... nothing that you have shown or said here helps anyone enough to be able to start to help.
for all we know your tune can be completely off the charts. Remember corrections are only to be adjust once your base tune is correct. ie. injector setup, req_fuel is correctly set, and your VE table tuned.
If you're having issues starting your car even when your engine is warm the issue is most likely a base calibration issue and this is why you won't get a good start no matter what the temp (hot or cold) and why changing your correction tables doesn't help at all. There could be a chance also that there is a hardware issue (faulty injectors, etc). But there is less of a chance of that from right now.
@someguy2800: Thanks for sharing your cranking table. I really appreciate your help!
I also jumped back with most of the parameters to a tune I made a couple of years before for my M52 turbo pump gas project. With that and your shared crank table I will make some trials within the next hours.
@all: I attached my current tune - your recommendations are welcome :-)
https://webmail.freenet.de/Cloud/?sh...d6574a1fe47e91
----EDIT---
...back from testing - well I can say… it worked :-)
I still have a minor issue that directly after engine starts firing it would need some automatic increase of the air flow rate for jsut a few seconds in order to avoid engine starts heavy alternating between 600 and 1400prm. Anyway I can compensate this by open the throttle very slightly for the first 5 seconds after cranking - then engine idles quite smooth.
So I would say: target for the day: achieved! :-)
Again thanks your for great support and as I already mentioned above any recommendations regarding my setup are welcome!
Thx
Torsten
Last edited by torsten; 06-19-2018 at 12:17 PM.
Thanks for the hint. Didn't notice this parameter since it was quite well hidden. Increased to 15 sec... now engine goes from cranking into stable idle autonomous.
Again thank you for your support.
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