How do you set up the ECM to start a cold engine?

[Mechanicaldan]

Hello all,

I'm very new to ECM tuning, and my learning curve is just about vertical right now, but I am determined to get this figured out.

I've gotten our engine started a few times, but it's not an easy task. I've done what I can to get the fuel map OK above 3000 RPM. It is sitting on the dyno right now, but I couldn't have the professor show me how to operate the dyno tonight because I spent a couple hours trying to get it running and semi-tuned.

How do you get these bloody things started well?

We are using a DTA E48EXP engine control module. The injectors are rated at about 10 lbs/hr, the fuel pump is set for 45 PSI, there is no water temperature compensation, no air temperature compensation, and no MAP compensation. I have the accelerator effect set at 45% increase for 0-1500 RPM, and the first row of the fuel map starts at about 3ms and goes to 12 ms, in 14 divisions relating to the TPS sensor being fully closed to fully open. I have the start up enrichment anywhere between 75% and 225% to get the engine started.

As for timing, during cranking the DTA is firing on either 0 or 1 tooth BTDC. The trigger wheel is a 32 - 3 tooth wheel. We are running a '98 Kawasaki ZX-6R engine.

I could really use some help, and would greatly appreciate any comments.

Thanks,

Cyclone Racing
Iowa State University
Engine Team Leader

[Mechanicaldan]

Hello all,

I'm very new to ECM tuning, and my learning curve is just about vertical right now, but I am determined to get this figured out.

I've gotten our engine started a few times, but it's not an easy task. I've done what I can to get the fuel map OK above 3000 RPM. It is sitting on the dyno right now, but I couldn't have the professor show me how to operate the dyno tonight because I spent a couple hours trying to get it running and semi-tuned.

How do you get these bloody things started well?

We are using a DTA E48EXP engine control module. The injectors are rated at about 10 lbs/hr, the fuel pump is set for 45 PSI, there is no water temperature compensation, no air temperature compensation, and no MAP compensation. I have the accelerator effect set at 45% increase for 0-1500 RPM, and the first row of the fuel map starts at about 3ms and goes to 12 ms, in 14 divisions relating to the TPS sensor being fully closed to fully open. I have the start up enrichment anywhere between 75% and 225% to get the engine started.

As for timing, during cranking the DTA is firing on either 0 or 1 tooth BTDC. The trigger wheel is a 32 - 3 tooth wheel. We are running a '98 Kawasaki ZX-6R engine.

I could really use some help, and would greatly appreciate any comments.

Thanks,

Cyclone Racing
Iowa State University
Engine Team Leader

[Charlie]

I'm confused, are there not MAP compensations at all on this ECU, or are you just not using them? I can't see how you could get something to start well with no MAP compensation.

-Charlie Ping
Auburn University FSAE 1999-present

[B Lewis @ PE Engine Management]

Hello All,

You don't need MAP if you are using TPS as an indication of load. In my experience, using TPS actually works better becuase the signal is more stable with the small, restricted, 4-cyl engines.

Dan - as for original question, let me offer what seems to work well for other engines with 12 lb/hr injectors using our engine management system.

- Fuel values in the table at the startup locations around 1.5 ms.
- Starting compensation that adds an additional 70% percent of fuel as the engine is cranking. This additional fuel degrades to nothing over 600 revolutions.
- Ignition advance of around 15 DBTDC.
- Water temp compensation that adds 70% more fuel at -40 deg F and tapers to zero at 120 deg F

The above factors all combine to give about 3.3 ms of open time as the engine is cranking. This of course degrades very rapidly as the engine warms up and runs.

With this combination, the Yamahas, F2s, F3s and F4s seem to fire right off. I can't imagine that the Kawasaki is much different. Good luck.


Brian Lewis
Performance Electronics, Ltd.
www.pe-ltd.com (http://www.pe-ltd.com)
"Complete Engine Management Systems for $760"

[Mechanicaldan]

Brian,

Thank you. I'll be giving it a try, and posting how it goes.

Cyclone Racing
www.cyclone-racing.com/fhome.htm (http://www.cyclone-racing.com/fhome.htm)
Iowa State University
Engine Team Leader

[Mechanicaldan]

I followed Bryan's advice, along with referencing some DTA example startup fuel compensation maps, and set the tables as follows.

The temperature compensation map adds 4% in steps starting at 60 degrees Celsius until the map ends at -20 degrees Celcius.

The first row of the main fuel map (1000 RPM) starts at 3 ms and increases in 0.25 ms interval.

The startup compensation map has the first column, representing 0 degrees Celsius, starting at 175%, 150%, 125%, 100%, 90%, 80%, 70%, etc. This repeats for the next 3 columns. The 40 and 50 degree Celcius column starts at 125% and follows the same pattern. The 60 and 70 degree columns start at 100% and decrease by 10%.

This allows the engine to start by just opening the throttle to about 25% open.

Some of the tuning difficulties may be the small 10 lb/hr injectors, and the unequal length log style plenum.

It's not perfect, but it's getting better.

Cyclone Racing
www.cyclone-racing.com/fhome.htm (http://www.cyclone-racing.com/fhome.htm)
Iowa State University
Engine Team Leader