1987 BMW 325is going VEMS, then turbo

[gox]

"When using a VR sensor the ECU must be configured to trigger on the rising edge of a tooth."

I read this http://www.vems.hu/manual/html/ch09.html#Detailed.Sensor.RPM.Config

My signal is great so I guess I must be doing something right.

Yes,i guess you are right,i missed out that one...

[danmartin]

I looked at my basic settings and the value for overrun_fuelcut was 2000 and overrun_fuelresume was 1900. My understanding of this is that the VEMS will cut fuel if RPM is greater that overrun_fuelcut and the TPS is lower than the threshold. The computer will resume giving the motor fuel at overrun_fuelresume. So what was happening is I was off throttle and there was no fuel above 2000 rpm however once 1900 hit it began adding fuel which would spike the rpm back up and then fuel would cut and this would continue. I have set fuel resume to a lower value 1100 RPM.

However the way it is working right now fuel is being cut when I shift and I feel like it is leaning the motor out for an instant once I get back on it. Should I fiddle with these values so that fuel stays on during shift or is it ok to have this situation?

Current settings:

[rob@vems.co.uk]

Try fuel cut over 3000 and resume of 2000, you can tune these figures to elimate popping in the exhaust and drivablility

[gox]

I finished everything today,now i need to set config and go try for spark and start the engine...

Are you guys using stock coil?
What is you Priming,Cranking,Afterstart settings?

Tnx

[BenFenner]

Yes, we are using the stock coil and distributor.

We'll try to get you our settings within the next 4 or 5 hours.

Edit: I'm sorry we aren't able to get you those settings yet. I've got a short paper to write for school, so I'll post Dan's info after that sometime tonight. You should have it soon enough.

[BenFenner]

These are Dan's settings for Priming, cranking & Afterstart.

You should be able to use these values as well. You might find they need tweaking for your own needs, but these work great on Dan's car. Maybe starting for the first time you might want to up the warm and cold cranking values a bit to give more fuel during cranking, but Dan's car starts up every time, no problem with these values.

[gox]

Tnx guys,you dont need to apologize i have all the time in the world...i`ll try everything later and get back with results

[danmartin]

My car is pretty much done except for little tweaks until I install my turbo. It should get to me Wednesday but who knows how long it will take for me to put it in. I still have to sort out oil delivery and return for it. Get the BOV flanges welded into my charge pipes, and make an exhaust. So hopefully this will come together sooner than later. Thanks again Rob for all your help!

[BenFenner]

Here's Dan's Injector Settings and Injector Outputs. The last two values in the Injector Output table are specific to his installation, so you shouldn't need to copy those.

Injector Settings:



Injector Outputs:

[danmartin]

Well I ran against Ben's brothers car tonight and the results were a bit disappointing. His car is a stock Nissan Sentra SE-R. Ben has raced his car against his brothers car before and with me in Ben's car it is an even race. Also Ben and I have raced before I got VEMS and our cars are neck-and-neck. So we figured that I should be able to pull a bit on Ben's brothers car. Well not the case  . He pulled on me pretty good so I don't know what to say, I guess I suck at tuning. I'm thinking somewhere along the process my Wideband settings got messed up. I'm going to re-configure it again and make sure I'm running 13:1. Here is my spark table.
 

Don't Mind the values over 110 kPa as they are not tuned!

[gox]

You might try with this one,its what Mattias recommends as starting point...

[danmartin]

Yeah that table is pretty good. I feel like my table is more aggressive and should provide more power (under 100 kPa) , but until I get the car on a dyno I can't tell for sure. I figure once I get the turbo and the clutch and am boosting to my hearts content I'll take it to the dyno and dial in the timing perfectly, until then I will use what I have as a base and tune conservatively under boost.

[BenFenner]

Those two maps looks almost identical at 110 kPa and under. A few values are tweaked, but Dan's current map looks like it could have even started from Mattias's map. It gives something good to use for above 110 kPa though.

[danmartin]

Well Ben was fixing his idle control solenoid wiring today and it inspired me to mess with my idle settings in VEMS. I hadn't really messed with them before because during cold start to keep the car idleing after crank all I needed to do way apply throttle for like 15 seconds and the car would idle around 500-600 rpm while cold. And it idles around 1100 rpm warm. But I figured since it is getting colder here it would be a good time to get idle set up because I don't know if keeping the revs up with my foot will last much longer.

The first thing I did was enable the idle solenoid with the engine off. It was set by default to some high frequency and I could here it click. I eventually lowered the frequency to 3. Started the car up, and the revs were way to high (1500) while my idle settings are set to 800 for warm and 1100 for cold. (The car is warm after the drive to Ben's home). So I enable PID and it doesn't help. I proceeded to alter the PWM table and make the warmer values 100(This makes no sense to me since 100 should correspond to idle open all the time, but it brought the values down for some reason). This I assume keeps the idle solenoid closed. Sure enough the car settles down to around 1100 rpm (usual warm idle without solenoid). So I figure I'll take it out for a drive. Immediately I notice that the response at low throttle input is way too high. I'm assuming the idle control is supplying more air than it should be. So I changed the idle tps threshold to 1% this didn't help. I then changed it to 10%. The low throttle characteristics are great but once I cross over 10% TPS the car bucks.

So I'm assuming I should leave the threshold at 3% and try to tune the PID settings. The laptop is charging so tuning is on hold. I know from basic controls class that a lager P gives faster response, a larger I decreases steady state error, and a larger D helps with overshoot and slows don the transient response. So for at least warm engine driveability I should look into increasing D to help keep the revs down in response to low throttle input, but we will see.

[danmartin]

So idle was set to channel "i6" and we changed that to "6". This made the engine rev to 3000 rpm so I changed the PWM values back to a lower number and this seemed to help. Still however the rpm targets in idle settings don't correspond to my idle. Some more tinkering ahead...