[Rasmus]

Hi guys,

i am on my journey tuning my lada niva 1,7 spi injection and it seems i am the only one dumb enough to tune a lada.
The lada is running great and can make any trip but it lacks some power (like 50 hp instead of the original 80hp).
I believe its my tuning (Ve and spark) that are not good enough.

So i am looking for any advise or opinion on my tune file and log file.
I m also really interested in any information about the typical Lada engine (1,5/1,6/1,7).

Log has been done on unleaded gasoline 95 (regular gasoline quality)

[jonbill]

I don't know your engine, but the spark map looks very conservative. I'd be adding 10 degrees extra advance everywhere above 3000 rpm. (unless you've already discovered you're getting knock with more advance?)
Your AFRs under load are oscillating between dangerously lean and quite rich. Your target AFR table is also quite lean under load - from 80kpa up I'd switch to 13.0 as the target.
Perhaps related - I think your injection settings (2 squirts simultaneous) aren't optimal for SPI - I'd try 4 squirts and 8 squirts and see how they work out. It may be that the 2 squirt setting is causing that AFR oscillation with different cylinders getting different fueling.

[Rasmus]

thanks for your quick reply !

I am also really concerned about that AFR oscillating and i dont understand it. AFR gauge is brand new and from a seirous compagny (AEM bosh). We experienced something like "kicking" or "shaking" when doing these run on log. We partially fixed it by adding more fuel at the VE table (around 3000 up to 5000rpm) but it didn't totally disappeared.

I observed that the AFR in the same range of rpm didn't osciliated when accelerating gently( cruising uphill).

My spark table is really conservative because i fear the knock ! i didn't experienced any knock but since i am a beginner on budget i'll work the spark table carefully.

Thanks for your advice i'll try it and report any change in behavior.

[PSIG]

I would look into your bouncing rpm/sec, versus your AFR. It could be a misfire due to Lambda, or ignition, or air leak or reversion to the O2 sensor, etc. Sometimes it's hard to tell if they are connected, and which one is causing the other. In this case, the rpm/sec is fairly consistent, where the AFR is cyclic. This might indicate the rpm/sec is the source, and AFR is following slowly. Maybe. This is what you need to discover.

AFR could be misfire, exhaust reversion, exhaust leak, bad connection, electrical noise, etc. Your fuel is not changing PW, your advance is not changing angle... Look at all your data, at every load and speed, in order to find more than one data that is changing like these, for clues.

Rasmus O2-rpm·sec.png (31.38 KiB) Viewed 409 times

Detonation is avoided by using proper fuel and developed timing. Incorrect timing either low or high can initiate knock. Try to test in order to find best timing as you go, so you have a good idea what it should be for areas you have not gone yet. The last area to tune timing is WOT, and you should not go there until almost all of your tables are tuned well. Work up to it.

If you don't have time for that, then I use better fuel that will not detonate in normal use, such as racing fuel, aviation fuel, real octane booster, etc, so I can freely tune. Tune well, then reduce octane to your normal fuel and carefully re-test.

[Rasmus]

Today test ride was an absolute disaster !

I did change my engine constant to 4 squirt per cycle wich is what i think is the correct setting as its a 4 cyl 4 stroke single injector setup : 720 deg crank = 1 cylce so to fuel all cylinder it should squirt 2 time per 360deg so 4 per 720.
Should i try the alternating setting or is this only for multi point port injection ?

I would like to focus on the issue with the AFR and rpm/sec weird behavior. I have several questions :
-Should the AFR be linear and stable during accel on the log ?
-what should be the correct behavior of the rpm/sec data on the log ? (stable / between certain value ?)

As i read your reply, it seems that i should focus more on hardware issue rather than tunefile settings ?

About timing and spark hardware on the car, all is pretty new (coils are new, spark plug and cable are too) except for the weird electronic ignition module (gm 10467214). What is funny to me is that most electronic on the car is from GM despite the car being made in russia.

Could someone suggest me a reliable ignition system that work good with speeduino (possibly on the cheap from a largely produced car) in the eventuality of needing to replace it.

Here are some logs, one is weird swinging idle for no reason. The other is my last accel during wich i experienced something like a spark rev limiter at around 3000rpm ( my feeling).

As some say : if it was easy everybody would do it.
(Still love my shitbox as despite all the abuse, she still gets my to work everyday)

[PSIG]

Yes, my point was that it could be mechanical, electrical, etc, and looking at clues can guide you for further testing. Testing includes making one specific adjustment, then looking at how it affected operation. Considering the results can guide you to the next test, and looking at those results, until you find the culprit. This is diagnostics. You are the detective, and these are the clues.

[EDIT] I didn't add GEGO to the graph or other data. How's that look? It could simply be you don't have the base tune stable enough yet, but that harsh rpm/s is odd. Perhaps a clogged injector, or 101 other things, and why we follow data. Can you use an IR temp gun or other means to identify if the exhaust is hotter of colder on one cylinder?

At this point you may be thinking you are up to your neck in this. It's OK, and diagnostics are not so much about technical knowledge, as attitude and mind-set. Don't feel lost - feel a challenge. The engine is trying to tell you how it feels, and you are simply looking for reactions from it so you can 'see' it. This is no different than a doctor poking you and asking "does that hurt?", or a parent trying to find why the baby is crying. Take a deep breath and remind yourself it's about attitude... then get to it!