had a ok tune now my AFRs are crazy without changing anythin

Tuning concepts, methods, tips etc.

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Supernova_6969
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Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

hi!

the two file are attached here.

I didn't want to post the msq since it's B&G code. but anyone interested in loking at it is my new best friend.
anyone who actually finds anything that helps with the problem gets a paypal beer.

I did notice (as i was copying the settings to a msextra empty file) that the displacement was set to 350cc and injectors to 30 cc/min. which is weird, as, even when multiplied by 6 (in case the guy programing it thought it was PER cylinder and divided everything by 6) it doesn't make any sense. I wouldn't expect this to create AFR chasing issues, though, just weird VE table numbers.. but what do I know.

thanks!
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
Supernova_6969
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Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

Hi guys.
Today, my car was running ok, but decided to iddle lean. Like i said, some days are weird. I expect it'll better better in a few days, like usual.
I did some logging, and did a light to light log. It should show iddle, some driving with a little shifting, and i think i managed to have a spell where i kept the throttle, map and rpm steady, to show how it varies even with no changes in those... Then again some iddle. Here is the file. You can see how the afr varies what seems to be o its own. Also, it starts iddling at a normal (but unsteady) afr, then becomes lean. This could like wet walls from the rich afr while driving that eventually evaporate, leaving lean afrs, but usually, my iddle afr is around 12-13, the super lean is just today (and other days where it wants to do this i guess).
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
nathanhardy
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Re: had a ok tune now my AFRs are crazy without changing any

Post by nathanhardy »

Try reloading the firmware
98 VW golf gti vr6 turbo 8:5:1 cr ported and polished full ferrea race valves train 276 cams custom short runner intake Borge 366 sx-e turbo forge wossner pistons, balanced rotating mass, limited slip 6 speed deka 750Lbs injectors on ms3pro completed AWD swap
Supernova_6969
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Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

Hi!
I'd falshed it a while ago, for whatever reason (another one of my post, something got corrupted and nothing was working anymore), and the issue was there before, and again after (i'd flashed 2,889, the original was 2.88), and ever since.

but just to be certain, i reflashed tonight. I actually, by mistake, flashed 2.92 (I was planning to flah the same 2.889, but I didn't realise what I was flahing was more recent).

I didn't go for the B&G 3.something code because I'm afraid i'd have to change stuff that I don't understand, so i'm sticking to close to my original set up. (still planning on moving to MSextra, once I'm certain my tune is set up properly.. I have another post on this, asking for help).

I went for a quick drive, but can't tell yet. I'll be driving more tomorow, i'll post again.

thanks for the support guys.
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
ewflyer
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Re: had a ok tune now my AFRs are crazy without changing any

Post by ewflyer »

I had a similar sounding problem on a project of mine. It turned out that a fitting in the fuel system was loose. When the engine was cool or warming up it would run fine (good air/fuel ratio numbers). But when the loose fitting got warm or hot from the engine heat it would begin to allow air into the system. The engine wouldn't stall but it would go lean at times (after sitting at a stop or during acceleration). In the data-logs I could see that the firmware was attempting to properly fuel the engine even as the lean-out events were occurring. When I realized what was happening I went over the whole fuel system and tightened all the connections. This solved my problem.
turbo conversion
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Re: had a ok tune now my AFRs are crazy without changing any

Post by turbo conversion »

ewflyer wrote:I had a similar sounding problem on a project of mine. It turned out that a fitting in the fuel system was loose. When the engine was cool or warming up it would run fine (good air/fuel ratio numbers). But when the loose fitting got warm or hot from the engine heat it would begin to allow air into the system. The engine wouldn't stall but it would go lean at times (after sitting at a stop or during acceleration). In the data-logs I could see that the firmware was attempting to properly fuel the engine even as the lean-out events were occurring. When I realized what was happening I went over the whole fuel system and tightened all the connections. This solved my problem.
You had air getting in the fuel system with out fuel leaking? :?

David
1976 Datsun 280Z L28ET Garrett GT35R T3-T04E stage3 50 trim 63 A/R housing custom grind cam 2000-6000 rpm 440cc injectors intercooled 18 lbs. boost
3" exhaust turbo back LC-1 o2 sensor Hallman manual boost controller EDIS 6 ignition batch fire 60mm throttle body 5 spd T5 borg warner 3.54 lsd
ashford
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Re: had a ok tune now my AFRs are crazy without changing any

Post by ashford »

ive had strange behaviour before for no apparent reason one time it was due to a ground bolt that had came loose and only gave issues when cold. i would start tugging wires to see if this makes any changes.

another more recent was a really unsteady afr while driving at rest it was ok. in frustration i slapped my wideband controller and it fixed the problem--- for a few days. if this sounds familiar try disabling ego and see if the engine runs fine ignoring the wideband.
Supernova_6969
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Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

ego is currently disabled... :-(
i did try something though. I set all my AFR table (not boosted) to 13.5. It's rich, but it'll help me make certain teh VE table is dialed in, and also, it'll be easier for me to figure out if there is a problem. I won't be guessing what AFR it's supposed to be based on the RPM and vacuum at all times. if it's not 13.5, there is a problem.
I guess once I fix up the VE table if indeed that is a problem, it'll also help me isolate why it's moving around so much...
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
ewflyer
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Posts: 233
Joined: Fri Jul 16, 2010 9:38 am

Re: had a ok tune now my AFRs are crazy without changing any

Post by ewflyer »

turbo conversion wrote:
ewflyer wrote:I had a similar sounding problem on a project of mine. It turned out that a fitting in the fuel system was loose. When the engine was cool or warming up it would run fine (good air/fuel ratio numbers). But when the loose fitting got warm or hot from the engine heat it would begin to allow air into the system. The engine wouldn't stall but it would go lean at times (after sitting at a stop or during acceleration). In the data-logs I could see that the firmware was attempting to properly fuel the engine even as the lean-out events were occurring. When I realized what was happening I went over the whole fuel system and tightened all the connections. This solved my problem.
You had air getting in the fuel system with out fuel leaking? :?

David
Yes, documented. The leak was occurring at one of the clamps on the intake line from the tank to the fuel pump. Just sitting static the system did not leak/drip. I guess the loose hose clamp wasn't loose enough to cause that.

But the combination of: A slightly loose hose clamp plus the suction of the pump (drawing fuel from the tank) and a little help from the heat of the engine softening the fuel line (rubber hose) and maybe even heat causing the metal of the hose clamp to expand a tiny amount... was apparently enough to admit air into the system.

You could see it happening as I ran through the data-log.
turbo conversion
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Re: had a ok tune now my AFRs are crazy without changing any

Post by turbo conversion »

Okay that makes since, it was on the suction side.

David
1976 Datsun 280Z L28ET Garrett GT35R T3-T04E stage3 50 trim 63 A/R housing custom grind cam 2000-6000 rpm 440cc injectors intercooled 18 lbs. boost
3" exhaust turbo back LC-1 o2 sensor Hallman manual boost controller EDIS 6 ignition batch fire 60mm throttle body 5 spd T5 borg warner 3.54 lsd
BigLou240sx
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Re: had a ok tune now my AFRs are crazy without changing any

Post by BigLou240sx »

Having some difficulty opening your msq, but looking at your logs, it seems your battery voltage is pretty unsteady and low. Everything working ok on the charging side? You get down to 12.0 volts in the running log, and at idle, are reading approximately 13 with some drops to 12.5. Perhaps an issue with your grounding or supply to your ms or indicative of an actual charging issue. I wanted to see what your msq showed for battery voltage correction of your injectors but couldn't get there. VE (if that's what Gve is anyways) stays steady, so you're not commanding the AFR swings by your VE table. Only thing else I saw jumping around was the x-tau stuff, but I have no idea how it works and can't say if that movement is contributing to your running condition. Try turning x-tau off and see if the problem corrects?

Have any datalogs from when your car was running ok?

Of course, I see that you're actively looking at switching to extra code, which will go a long way with obtaining support here, so consider this post OBE (at least the suggestion to turn off x-tau) if you've jumped in. However, battery voltage issues should be looked into regardless of the firmware used.
1990 Nissan 240sx / SOHC KA-T / DIYPNP
Supernova_6969
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Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

Hi lou.
Thanks. I realised that myself just this week....
I think the ms is grounded straight to the engine but i want to double check it..
The alternator in my car IS pretty weak (barely adequate from factory, recently repaired and in good shape though), but outputs a steady voltage per rpm, i think..., that much variation at iddle does not make sense to me either
Ill check out the ground and the see...
The only issue is that all the wires coming out of the ms are the same colors (stupid idea if you ask me) so i' have to chase which ones are grounds and then see if they are good. I also want to see if the power is delivered properly.
Ill post about that soon.
Last edited by Supernova_6969 on Mon Sep 19, 2016 7:10 pm, edited 1 time in total.
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
Supernova_6969
Helpful MS/Extra'er
Posts: 75
Joined: Fri Sep 19, 2014 7:49 pm
Location: Montreal, Quebec, Canada

Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

just in case anyone reads this all the way through even though it's an old post, I figured that one part of the problem was the location of my IAT. it was on the manifold and would constantly be heatsoaked. that made the MS2 think I was breathing very hot air (up to 200degrees) and it was leaning things out to make up for that.

I still have other significant issues, but moving the IAT to before the throttle plate really helped my car run more consistently when it starts cold. (hot start is something else. see here... http://www.msextra.com/forums/viewtopic ... 34&t=63980

thanks for all of those who commented.

oh, I haven't changed to MsExtra yet. it's still a project, but I'm not particularly confident starting from scratch (too many things I don't know) and I relaly thought the IAT sensor relocation would have done more....
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
Supernova_6969
Helpful MS/Extra'er
Posts: 75
Joined: Fri Sep 19, 2014 7:49 pm
Location: Montreal, Quebec, Canada

Re: had a ok tune now my AFRs are crazy without changing any

Post by Supernova_6969 »

Hey guys. resurecting here, but I want to bring some closure, in case someone reads this.
my car was all over the place for 2 years, even with all sorts of tweaking.

I eventually realized part of the problem was heatsoaking of the Intake air temperature sensor, which was screwed into the aluminum manifold.. I first moved that to the pre-throttle plate, and that helped a whole lot. still was getting lean AFRs on hot restarts, which is a major issue with many people. I played some with the Air density modification table, and that helped, although when the air was genuinely hot, it made everything too rich.

In the end, I ended up changing the injecotr dead time, which was all wrong, and FINALLY moved over to MsExtra this week end.

so far, I've run it 2-3 times, and it's been pretty good, with only a hot start issue, which I'll be working on.

so many things worked towads making my car work better, but one of the easiest and the major change was the sensor relocation....

hope this can help others!

seb.
1983 Datsun 280zx, inline 6 2.8l, T03/04 turbo, Megasquirt II.
Bought built like that, but completely untuned. Getting better and better one VE table box at a time.
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