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looks good! I’m ok with my adapters/cable routing for now but maybe in the future I’ll change things.
When you look up horsepower/injector size estimations, the NA injectors are already on their limit. In general, injectors perform best at an 85% duty cycle, so even stock cars may benefit from bigger injectors.
As I want to increase head flow and use a mild camshaft soon, the bigger Volvo injectors are a must.
Another thing I’ll definitely do in Vemstune is to half the req_fuel time and double the numbers in the VE table. Because they go to 255 theoretically, limiting the values to 100, 120ish is using only half the possible resolution.
I think the "req. fuel ime" is important to do "by the book" 6.49 x ( cc of engine (divide by) no. of injectors (divide by) injector flow in cc per minute) this way the ecu can predict what the injectors are going to do, While you are at it, the injectors need to be configured correctly, I adjusted voltage correction by turning on lights and fans at same time to get a voltage drop, then adjust so as not to effect the lambda/rpm, the injector ramp time, I adjsted it to get the flattest ve reading up the rpm sites at a given load
these are practicle ways of doing this that I figured should work, if anyone thinks different, I'll be happy to hear it
Could you please share your current config with Volvo injectors and working economy gauge?
I've ordered same, they will arrive soon.
Already done 700 km (~400 miles) with VEMS, still struggling with some random issues, but overall everything is great
Here you go. Attached is the VEMS-Config of 12-31-2019 with 0 280 155 759 injectors, wasted spark and working eco gauge. EDIT: another VEMS Config attached without WS
Note: My 944 is no stock engine. Mods: Wasted spark, larger camshaft, throttle body, headwork, extrude honed intake, no catalytic converter, 4-1 headers etc... So your needed tune could be a bit different.
Here you go. Attached is the VEMS-Config of 12-31-2019 with 0 280 155 759 injectors, wasted spark and working eco gauge.
Note: My 944 is no stock engine. Mods: Wasted spark, larger camshaft, throttle body, headwork, extrude honed intake, no catalytic converter, 4-1 headers etc... So your needed tune could be a bit different.
Thanks
Wanted to make sure that PWM is off, req fuel is around ~12 and nothing else is changed.
BTW, I also run with 4-1 header (lindsey), but it's so loud - I will return back to original one.
2) The analog tachometer on the dashboard doesn't work anymore. Is there any wiring problem on the VEMS ECU side? It was working just fine with the stock ECU. I found these settings somewhere in the web and tried them, but they didn't do anything (see the picture for the reference)
3) VEMSTune application crashes randomly from time to time. So, it's a bit annoying I installed and using the latest version.
4) It seems like VE Tune by statistics and Live VE Analyzer tools don't work for me, because I'm getting this weird error: "Filter Failed!" Not sure what it means. So, I can't use the Auto-Tune option.
Please see the pictures of the setup and how bad the car is running for the reference.
So, at this point I'm pretty frustrated because the car is just stuck on the driveway in front of the garage and I'm desperate for any help or guidance. Would anyone be able to answer the questions above or redirect me to anyone who can help me to configure it and finish the tuning?
Tach:
my old VEMS config has the settings as "S259", channel 3, custom, divider 17. Always worked OK.
Crashing: I never had that issue, it might be the PC rather than the app.
Autotune: sometimes if the numbers you put in are too small it doesn't work and you need to give it time to do its job.
increase the "authority" (i forget the term on VEMStune) of how much the software can adjust VE on the fly and it will chip away.
can you upload the config file you have here and i can look at it? i have lots of my old configs but they are going to be all wrong for your car.
I run Megasquirt so am not familiar with VEMS but a few things:
1) Did you set/adjust base ignition timing? Usually requires you to fine tune the settings in your standalone to get it completely in sync with the motor. You set your VEMS/standalone to a static timing, say 10 degrees (this overrides the ignition timing maps) and then put a timing light on it with 10 degrees advance and adjust your trigger angle to the light matches your mark.
2) Ignition map, based on the gauge screenshot this looks normal, but not enough info to make a judgement on this - 10-30 degrees advance is within the range of what I see on my car (varies widely between part throttle cruising vs WOT vs idle) - idle timing I have set to around 15 degrees - would have to see your full timing map. I would not worry about this for now until you get the car idling well.
3) Fueling - hard to know what the issue is. It could be your warm up enrichment kicking in causing it to run too rich. I suggest dialing that down or getting the car up to normal operating temp and then dialing down the fuel in your fuel table (Should be you VE table in MS). Warm up enrichment uses your VE table and then adds a percentage of fuel above that for cold starts and tapers it off as temps increase. Its important to set your idle range fuel VE values when the engine is fully warm and then let the car cool down and then configure your enrichment again once the car is cold. Use your wideband - my car (S2) idles best at around 12.5-13.5 AFR when fully warm. When cold it likes to be in the 11-12s
5) Req_fuel - this is a variable in MS that controls all the base fueling. It is calculated using your injector size, your displacement among other things. Im not sure if VEMS has a similar variable (it likely does) but make sure thats also calculated correctly.
Lastly, VEMS has some documentation here, as Im sure you already know but just in case, as well as email based support, which I would suggest: https://www.vems.com/documentation/
And with any standalone system, its not going to run 100% perfect out of the box, its going to need to be configured, tuned and fine tuned (unlike a chip or MAF kit). Theres a steep learning curve to this, but do your best to use google "VEMS <question> forums" could yield some answers, as well as youtube. The nice thing about standalone is that the same principles apply regardless of what engine it is controlling, so you can sometimes find answers to your questions even if the car in question isnt a 944. There are likely similarities between MS and VEMS and also differences.
Good luck
Last edited by walfreyydo; 07-27-2023 at 11:26 AM.
Tach:
my old VEMS config has the settings as "S259", channel 3, custom, divider 17. Always worked OK.
Crashing: I never had that issue, it might be the PC rather than the app.
Autotune: sometimes if the numbers you put in are too small it doesn't work and you need to give it time to do its job.
increase the "authority" (i forget the term on VEMStune) of how much the software can adjust VE on the fly and it will chip away.
can you upload the config file you have here and i can look at it? i have lots of my old configs but they are going to be all wrong for your car.
Apparently, I missed one step - I didn't hook up the throttle body to VEMS. So, I ran a vacuum line and I can see the MAP sensor readings.
I set tach to S259, channel 3, divider 16 and it works now.
Then I updated ini files and started the car. It still runs really bad and doesn't idle well. Anyway, I waited until it warms up and started playing with Req Fuel settings.
By default it was 17, but according to the formula in the documentation I set it to 15.96 = 6.49 * (2479 / 4 / 252). 252 cc/min equals 24 lb/hr, but the lambda readings were too high on idle (it was idling 550 - 650 rpm and it doesn't seem to be stable). Then I found a value for Req_Fuel that gives lambda between 0.95 - 1.0, and it was 24 or 25. Apparently, it's too much, because my catalytic converter was glowing red hot!
I'm sure that some settings are messed up, but I don't know which ones. Also, it sounds like the car is not running on all 4 cylinders for some reason... not sure what to do about that either.
Here is my last config and some logs - attached.
If you can take a look at them, I would appreciate it a lot! Maybe you can find something that is missing or very wrong with it.
@walfreyydo, Yes, I'm very new to this and there are so many things that I was not aware of... After all that, I feel like I'm a complete newbie into cars LOL, but before I thought I was quite experienced... I don't think that the base ignition timing needs to be adjusted for base VEMS setup, but I'm talking to people in VEMS FB group and trying to use as many resources as I can just to avoid time difference, you know.
Playing with reqfuel is a quick way to see if you need more or less fuel. But the better way to do it is to calculate the approximate reqfuel value and then adjust the VE table cells to get your actual AFR in line with the target AFR.
Your car may run happier at 0.9-0.95 lambda warm; it might not be as happy at 1.0. It helps to turn off/unplug your IAC valve and adaptive idle timing setting too while trying to get a stable idle. The engine should be able to idle stably just with the air coming leaking around the throttle blade, with fixed timing and a good AFR. The adaptive timing and IAC are add-one to help with extra load from AC or electric fans kicking on.
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I'm sure that some settings are messed up, but I don't know which ones. Also, it sounds like the car is not running on all 4 cylinders for some reason... not sure what to do about that either.
Here is my last config and some logs - attached.
If you can take a look at them, I would appreciate it a lot! Maybe you can find something that is missing or very wrong with it.
.....
Yes, there are indeed some settings messed up. But don't change everthing in one go. Just do it step by step. Below just two of your weird settings.
1.) Set your IAC PWM Frequency to 100 Hz. Currently it won't work, because no value is set. 2.) Warm up enrichment 110.5% when coolant temp is 80°C is nonsense. Turn down your warm-up enrichment curve.
suggested basic curve
Try some lower values like this.
EDIT: IAC close delay. I disabled "close delay" by 256. I suggest doing so as well. Better low rev cruising behaviour.
Playing with reqfuel is a quick way to see if you need more or less fuel. But the better way to do it is to calculate the approximate reqfuel value and then adjust the VE table cells to get your actual AFR in line with the target AFR.
Your car may run happier at 0.9-0.95 lambda warm; it might not be as happy at 1.0. It helps to turn off/unplug your IAC valve and adaptive idle timing setting too while trying to get a stable idle. The engine should be able to idle stably just with the air coming leaking around the throttle blade, with fixed timing and a good AFR. The adaptive timing and IAC are add-one to help with extra load from AC or electric fans kicking on.
When setting Req Fuel to the value that it's supposed to be "16" (based on the formula calculations and the stock injectors) the Lambda readings are way too high - 1.87 and it's idling around 500 rpm with the warm engine (75C and higher).
I haven't tried to disconnect ICV yet, just because I was told to test Injectors and Ignition using the testing functions in the VemsTune app. So, I did those tests in addition to resistance tests of the spark plugs, wires and ignition coil - everything looks fine.
Here are the videos and pictures of my tests:
Then Peep keeps saying that the wires are plugged incorrectly and I need to rotate engine to the top dead center and test the spark on the first cylinder. It sounds so bizarre to me, because I didn't touch anything when swapping the factory ECU to VEMS.
I don't really understand that. So, I'd like to hear other opinions on that.
Here is how the wires are:
Yes, there are indeed some settings messed up. But don't change everthing in one go. Just do it step by step. Below just two of your weird settings.
1.) Set your IAC PWM Frequency to 100 Hz. Currently it won't work, because no value is set. 2.) Warm up enrichment 110.5% when coolant temp is 80°C is nonsense. Turn down your warm-up enrichment curve.
suggested basic curve
Try some lower values like this.
EDIT: IAC close delay. I disabled "close delay" by 256. I suggest doing so as well. Better low rev cruising behaviour.
Thanks H.F.B.! Should I try to change these settings after trying to run the car with ICV unplugged or you think I can adjust these settings and run the car?
04-11-2020, 08:57 PM
I installed and using the latest version.
