Bosch 42lb Green injectors maxing out around ~10psi?

[ForcedFirebird]

He is running rich, VE's are too high. I was working with the tune, just haven't had much time lately to help more - we have a 14hr enduro in the e30 this weekend and blew the motor at the last event, so kinda been scrambling - also had one of our regular sprint racing clients blow 2 s52's int he last month (seems like there's something going around :(). Got it squared away for lower boost, tracking down an issue, since then the boost was increased and hasn't been compensated up there yet.

Last log I looked over was only at 65% duty at ~8psi.

Fraser, you can use the auto tune feature for cold starts. There's another tab in the function "warm up enrichment 1". Start the car on a cold day (of course with the engine cold), and turn on the auto tune - it does a decent job of ironing out the cold starts.

[Fraser]

Thanks again for all your help Varg. I've got this pretty well under control at this point. Haven't had much time to drive the car or work on the tune, but I now have a solid grasp on what needs to happen- the higher boost squares are simply way too rich, I just need to spend some time getting them dialed in.

The cold start tune is also improving the more I work on it, it's tolerable right now but not great. I do think the 42# injectors and living at 7500 feet aren't a great combination. I regularly have to cold start it around 11k feet elevation and it's particularly cranky. But what do I expect.

Thanks for all your input everyone!

[varg]

Make sure your injector constants are correct and lean it out. Sounds like you're running super rich. If your injectors are still close to tapped out once you've got your AFR around 12.5 instead of 10, you may be having fuel pressure issues. If fuel pressure drops, your tune will have unnecessarily large duty cycle because less pressure means more open time for the same amount of fuel. If your wear parts (fuel filter, pump, regulator) aren't in good order, you could have insufficient fuel pressure under boost.

FWIW, duty cycle is the percentage of time the injector is open vs time to complete one cycle. Incorrect injector constants wouldn't really skew the duty cycle since it only cares about open time, they'd just make your tune look goofy.

I can almost guarantee that your cold start issues are not from having 42lb injectors vs 30lb/hr. You just need to spend more time tuning your cold start settings. To be fair, it's one of the harder/longer things to tweak on any megasquirt install.

Yeah, he's having tuning issues. Tuning is tricky to teach yourself to do. Strictly speaking, even properly tuned he could have some limitations based on injector oversize. 42lb/hr isn't huge but it's big enough that he could run into minimum pulsewidth instability at idle, especially considering altitude. Most injectors don't like to go below 1.5ms, and the bigger the injector, the more likely you are to wind up with a rich idle because the injectors are up against their minimum pulsewidth and don't fuel consistently below it. It's a little better with sequential injection than the batch/alternating batch we run on M20s.

[Fraser]

that and maybe get more modern injectors when u upgrade because they'll max it soon i'm sure. Ford green bois right?

No, Bosch- but I'm sure you're right, I don't think anyone would consider them modern...

I also agree with the cold start tuning stuff, I need to keep working on the tune.

[LowR3V'in]

that and maybe get more modern injectors when u upgrade because they'll max it soon i'm sure. Ford green bois right?

[Jaxx_]

I can almost guarantee that your cold start issues are not from having 42lb injectors vs 30lb/hr. You just need to spend more time tuning your cold start settings. To be fair, it's one of the harder/longer things to tweak on any megasquirt install.

[Fraser]

Wow, how much power are you running on the 30#s? I would consider going to smaller injectors at some point to get some of my cold start issues cleared up...

[tschultz]

I was going to say.... our altitude and 10psi shouldn't be pushing those injectors! I downsized to 30#'s on my M30 to try and have excellent performance throughout operation for my car up to 160kpa.

[Fraser]

Shoot me a datalog with the current .msq, last one said 65% if memory serves me correctly. I owe ya a beer/soda. :p

Will do- I love beer! I think my current overfueling issues had to do with hitting KPA values that hadn't been hit before and were thus tuned conservatively (really) rich...

I'll send over the most recent log and MSQ and see what you think... I'd like to run 12-14psi regularly which looks like shouldn't be a problem with the current hardware once I get the tune a little more dialed. Other than my stock clutch which is starting to slip like a bastard and needs to be replaced ASAP.

Thanks guys!

[ForcedFirebird]

Shoot me a datalog with the current .msq, last one said 65% if memory serves me correctly. I owe ya a beer/soda. :p

[Fraser]

9.8arf @ 11psi it's drowning.

Even your targets are 11.5afr that is way too rich for the boost.
try 12.5 afr.

Geez, no kidding. I've been running around at 6-7 psi for so long while I was troubleshooting a spark miss I guess I never noticed those higher boost squares running so rich. Obviously that would explain the duty cycles being so high in those same areas also.

I'll work on those tables a bunch over the next few days and see what it looks like.

Thanks for your help!

[LowR3V'in]

9.8arf @ 11psi it's drowning.

Even your targets are 11.5afr that is way too rich for the boost.
try 12.5 afr.

[Fraser]

Thanks for the info- that's not the first time I've heard it's wise to rewire the pump with it's own circuit and relay.

Here is a link to the current tune and a couple logs- one is ~12 psi and is busting 100 DC, another is back down to 10psi and still hitting near 90, which I do not believe to be correct. Thanks to whoever is interested in looking at them...

https://drive.google.com/open?id=1rIBjjn6mN3kHOBavmenkCkbqFZZT2xzv

[LowR3V'in]

if it reads 100dc+ yet it still responds to increasing ve
then it is not at 100.

idk the limits of the stock pump or the draw but i do know the stock wiring sucks
and if u wire the pump from the batt. on a relay it will get you where you need to be.
if not for this then for future pump needs. stock wiring is shit.
my 255 was going lean and wiring it this way gave me that extra needed fuel

10psi on stock hx35 setup i don't think you are maxing them out.

i am rusty on MS settings but your dead time and fuel requirements are not right.

[Northern]

check your fuel pressure too, maybe something pump or regulator related