[Jason Rouillard]

Hi,

With my first Speeduino project, i have some problems with cold start. When I try to start, engine hesitated and die. Some time engine do kick back. I try to play with somes parameters and nothing help. I try increase/decrease cranking advanced, cranking enrichment, ASE. My VE map is tuned and last two days i do warmup adjustment with tuner studio autotune.

I do some log when i start engine and some times log tell that engine rpm rise to 7000 RPM and more... I don't understand why...

Some times when i crank engine, speeduino not detect rpm.

When engine is hot, it's more easy to start engine.

Can someone tell me how i can tune cold start ? Do you have a step by step to achieve best result ?


I attached some logs and the tune i use for start.

My speeduino is 0.4.3c. My engine is a 2200 sfi from a chevy cavalier 2002.

Thanks a lot for your help.

[PSIG]

Hi, Jason! I have not reviewed your files yet, but I'll post some guidelines for cold-start tuning that I've done before.

There are several approaches to tuning cold start and warmup. This is mine. It is logical progression, and relies on the tune being very good for idle and high-idle, and warm-restart very good. The warm-starts should be fast and snappy. The cold start and warm-up settings add to those warm settings. That also means other stuff like injector dead-time, voltage corrections, dwell, warm cranking fuel, etc, must be good, or you will get frustrated.

CE = Cranking Enrichment
ASE = After-Start Enrichment
WUE = Warm-Up Enrichment

1. Perfect WARM tune
2. Perfect WARM restart prime
3. NO added COLD CE, ASE & WUE from warm
4. Test COLD prime to quick-fire
5. Test COLD CE fuel for good rpm surge from firing to above cranking RPM
6. Test COLD ASE to run ASE duration
7. Test COLD WUE to continue run from ASE end, to WARM

As ASE and WUE overlap, you can go back to ASE and adjust if WUE changes, so the combination area of both is solid.
Remember - you can click on functions in TunerStudio to (sometimes) get info about that function and settings.

Note in this - warm-up tuning is the only time I may do a "hot" start with the O2 sensor, so it reads on first cold crank. I have not experienced any sensor failures or shortened life with this limited special use. Warm-up reads about like normal running Lambda, and it just takes more fuel to get there. Log everything.

Other links where I've described my methods are below, or do a search for "warmup" and "warm-up". Other systems may function similarly, but will not be the same as Speeduino:

viewtopic.php?p=40236#p40236 Re: Idiot's guide for cold start tuning

viewtopic.php?p=36305#p36305 Re: Successful Initial Start

viewtopic.php?p=49395#p49395 Re: Tuning start-up (cold and hot)

[FiatDuino]

Jason

Ambient temperature around 1-2 deg C, so this will be a serious test of a cold start.
Do you have any warmer starts already working, or are these the first starting attempts?


Some things to note about the current tune:

The battery V not reading any values, every log shows 0 volts. I am not sure what the problem would be.
Without any record of battery voltage, any adjustments depending on battery voltage will just be a single, minimum value.

TPS may need to be re-calibrated, it's recorded as a minimum value of 3 or 4%.
The ADC range showing in the calibration is fairly narrow. 24 for closed throttle and 217 for wide open.

The maximum allowable ReqFuel for this setup is 25.5 msec. This tune is set at 24.2 msec, so it seems quite high.
It is the result of the required fuel calculator, I assume. What injector size is being used here?
When calculating ReqFuel, stoich has been set at 12.5. What fuel is being used?
A mixture of 40% ethanol with 60% gasoline would be close to a 12.5 stoich, whereas 100% gasoline would be closer to 14.7.

I see that you have an exhaust pressure sensor, an EMAP 2 bar GM sensor. EMAP is showing 150 kPa with the sensor using pin A0

Fuel pressure in the log is 73 PSI. Do you have a fuel pressure regulator to adjust that pressure to 43.5 psi?
Also the fuel pressure sensor is using pin A0. This appears to be in conflict with the EMAP sensor. Is that right?

pin A0 for fuel pressure and emap.png (387.15 KiB) Viewed 517 times

Dwell is set at 8 msec (both cranking and running). What coils are being used?
Voltage correction for dwell is using 110 (resulting in an effective dwell of 8.8 msec); this correction is the same battery issue mentioned above.
Most dwell settings I have seen are in the 3.0 to 3.5 msec for running and perhaps 4.0 to 4.5 for cranking.


WUE vs CLT setting show WUE correction going below 100 at temps above 69 C. This will result in pulling some percentage out of your fueling PW.
WUE is supposed to end at a value of 100 when you hit the temperature that you call 'warmed up'.
I guess we have to get the engine started and up to temperature before this would be noticeable.

I am interested in getting up to speed on your setup so I can understand it better.

[Jason Rouillard]

Hi, thank you for yous responses and your time.

I want to use speeduino on a derby car. Stock computer are limited in tune and have immobilizer and limp mode. HP tuner can unlock stock computer but HP Tuner is expensive. With Speeduino i can program it to achieve some results.

My Speeduino have jumper 1, 2 and 3.

Do you have any warmer starts already working, or are these the first starting attempts?

Yes, engine run and in october i tuned my VE table and ignition table.

The battery V not reading any values, every log shows 0 volts. I am not sure what the problem would be.
Without any record of battery voltage, any adjustments depending on battery voltage will just be a single, minimum value.

: I shorted my voltage reading circuit when i try to adjust my IAC. My Stepper driver motor not worked so I try to find the problem with my multimeter and i shorted... I know it's not good but I put no correction voltage in configuration.

The ADC range showing in the calibration is fairly narrow. 24 for closed throttle and 217 for wide open.

: What do you mean ?

The maximum allowable ReqFuel for this setup is 25.5 msec. This tune is set at 24.2 msec, so it seems quite high.
It is the result of the required fuel calculator, I assume. What injector size is being used here?
When calculating ReqFuel, stoich has been set at 12.5. What fuel is being used?
A mixture of 40% ethanol with 60% gasoline would be close to a 12.5 stoich, whereas 100% gasoline would be closer to 14.7.

: I want 12.5 to cold my combustion chamber. In derby, engine become very hot, so i need a lot of gaz. I use stock injector (17lb/hr). I never find on internet injector dead time so i put 1 ms.

I see that you have an exhaust pressure sensor, an EMAP 2 bar GM sensor. EMAP is showing 150 kPa with the sensor using pin A0

: I don't have, so i will remove this configuration.

Fuel pressure in the log is 73 PSI. Do you have a fuel pressure regulator to adjust that pressure to 43.5 psi?
Also the fuel pressure sensor is using pin A0. This appears to be in conflict with the EMAP sensor. Is that right?

: I don't have, so i will remove this configuration.

I don't have, so i will remove this configuration.

: When i do my first try with Speeduino, engine run like crap, so i increase this value to 8 and it's fix my problem. I have a stock ICM with Wasted Coil. I never find on internet the dwell time for this coil.
https://www.rockauto.com/fr/catalog/che ... +coil,7060
http://www.useasydocs.com/details/GM_DIS.htm

WUE vs CLT setting show WUE correction going below 100 at temps above 69 C. This will result in pulling some percentage out of your fueling PW.
WUE is supposed to end at a value of 100 when you hit the temperature that you call 'warmed up'.
I guess we have to get the engine started and up to temperature before this would be noticeable.

: Yes, i want my WUE adjuste my fuel ratio when engine become very hot (150C) and more.

My problem when i try to start engine is that speeduino detect some high rpm, so it increase ignition and make some kick back. I have a shielded wires and my ground shield is connected to battery. My wires are also twisted. I try to put some trigger filtering and it's not fixing the problem. The problem occurs some times. Engine start better when it's hot. I have a max9926 VR Conditionner.


My coil pack is directly grounded on engine.

I want to fix this problem before adjusting cold start. I don't know if this problem become from setting or my setup.

Thanks for your help.

[FiatDuino]

I was referring to the TPS calibration range. It is found under the Tools tab.

TPS calibration .png (418.15 KiB) Viewed 378 times

[Jason Rouillard]

I was referring to the TPS calibration range. It is found under the Tools tab.

: I fixed it !

My problem when i try to start engine is that speeduino detect some high rpm, so it increase ignition and make some kick back. I have a shielded wires and my ground shield is connected to battery. My wires are also twisted. I try to put some trigger filtering and it's not fixing the problem. The problem occurs some times. Engine start better when it's hot. I have a max9926 VR Conditionner.

: I tried to change Shunt. I cut the one on VR Conditioner and I put new resistor between crank sensor wires. I tried resistors of 10k, 30k, 60k, 100k and 300k and it doesn't work anymore. I have rpm and spikes when I start. I don't understand what my problem might be !