NefMoto

Hiya Guys, I've recently gotten hold of some Bosch 550's, been dialling in KRKTE/TVUB/etc. and I'm noticing that every now and then (randomly) there's a lean spike.

It's not as a result of requested lambda, but it does appear that the IDC is cut, I can't figure out why...

I thought it maybe as I'm going slightly over the max map pressure, but it doesn't always do it in that area, it's pretty random.

I've had LTFT's disabled today also and done a bit of fiddling in case it was simply the injectors were out. I got some clean runs (no spike) and dialled in KRKTE, then moved onto cleaning up/fine tuning with FKKVS fixer which is where I noticed the spikes were back, along with this rich condition after ~4.5k (this can all be seen with frm_w also).

I've attached a 4th gear log (PID needs some work again as it's adjusted for a damn cracked hotside which has been replaced, now spools up way faster).

Any opinions/ideas? Am I missing something silly?

Edit

Oh, btw kfkhfm, kflf, fkkvs all 1's it still does it... Also when comparing different logs, I see no correlation with injector on times, it doesn't appear to be dependant on those either

log ps_w

you're breaking all the rules.

if you are going to run this close to the map limit, you need a 5120 file or you have to dramatically underscale the MAF during high load, then compensate for it in fueling (really really bad hack).

Thanks Nyet, I'll try to get a WOT log with it tonight.

Yes, I'm aware that there are issues when it's close to/over the MAP limit, hence I'm wondering if that is the cause (it's looking like it most likely is).

It just seems a little odd that it was fine on stock injectors - maybe they were just dialled in much more perfectly so the effects aren't so pronounced? Nothing else has changed.

I've already started a 5120, looks like I'll need to get my backside moving and get it done.

You can always log ps_w to be sure.

Also, definitely get a wideband.

Yea I realise I should always be logging it, it'll be on my permanent config file from now on.

Also, it's a wideband ecu... I've also got my own wideband which I've used just to make sure it's accurate (although testing around 6 months last).

ETA: it's an lm-2 so it's a big ugly handheld thing, not a nice gauge that I can mount nicely - might look into one though.

Not got a log as I'm out and on the phone currently, but I did a quick under scale of the maf (ps_w was barely maxing out).

However, the exact same symptoms occur... Random spike and then large correction at the high rpm (that's not needed) making it go mega rich.

Any ideas where to start investigating further?

Post logs... Don't need lm2 logs, ecu wb is fine

There's a log in the OP, exactly the same thing, although when I'm home I'll post the recent one with quick under scale.

Just some thoughts I've had... Spark blowout/misfire which is sending the trims wildly off? Just speculation though, odd it only happens once if it's that. Plugs are new etc. worth checking though I guess

I've attached a zip with a few logs in - most are done in 4th now as it's damp out and there's wheelspin higher up in 3rd.

Hopefully the log names are self explanatory.

I put the MAF scaling back to normal after I logged it with it underscaled slightly, it was just a quick test.

Thanks for your time!

Quick update (and an odd one!)

The mrs suggested I raise the afr again like before I installed the injectors and test (random eh). So reluctantly I did, raised it a little to 12 and it's fine! No spike...

However, I managed to hit egt protection during a run which enriched the afr, as soon as it enriches to ~11.7 it spikes lean and then goes on as normal.

Any ideas? I'll post a new log but will be tomorrow night now, busy weekend!

Just a bump - confirmed that it's definitely something to do with it getting to 11.75 afr

As soon as it gets to that, requested/actual it has that spike. I don't think it's anything to do with the ps_w cap, open to any ideas people may have?

Think I'm going to go through other fuelling maps and see if there's anything around the 11.75 mark it could be flipping to for a quick calculation before returning back to lamfa (this is how I'm fuelling atm, plus egt protection when temps are high enough).

What does IOT do at that point?

Sorry Ddillenger, IOT?

ETA - Sorry! Injector on time, it also dips hence it seems to be a requested thing (requested afr does not change) - it's in the logs attached also.

I've not been near the car all week (been working in London, can't wait to leave this underground malarkey behind!)

Anyone got any thoughts to this I can start with over the weekend?

So, I've found that I get an IOT/IDC dip when I hit afr 11.75 (or 0.80-0.79 lambda)

I've also found LALIUSMN (Minimum measurable lambda?) - It is originally set to 0.7996, maybe just a coincidence that my issues are here though...

Next step I guess would be try the oem injectors and see if the same thing occurs.

Well... As to the how's and whys, I can't answer them.

But lowering LALIUSMN seems to have sorted this issue.