Any cures or ideas for what can be done to assist starting from cold when using an aftermarket ECU?

Fitted a new heavy duty 097 battery which has helped a lot (had to jump start it from cold with the old 085), but still takes a hell of a lot of turning to fire up

Zetec on weber Alpha throttle bodies, heard theyre all like this from cold though.... (why the hell is that anyway?!)

 

run better cables to the ecu

is the problem voltage compensation or temperature corrections?

 

only like it if not setup properly sounds like all the corrections are wrong

 

....and that means?

 

you need to measure the voltage at the ecu terminals when cranking from cold!

 

its a posh way to what i said lol the ecu will have water/air/battery compensations/corrections that need to be setup in the ecu

 

Basics first, what ecu is it?? as I know one that doesn't like starting!!

 

Weber Alpha ECU..... All part of a throttle bodies/ECU/loom plug and play kit.

Don't remember anything in the instructions about corrections though...

 

Run a seperate cable for the ECU direct to the battery. If you have a battery in the boot and are teeing off at the front before it goes the starter it will have too low voltage when cranking.

 

If it dropped low enough to not work the ecu it would not turn the engine over, DC motors as in starter motor are VERY voltage sensitive.
I suggest you first clean up all connections, and make sure the cu is earthed where it should be, then as said check power at ecu while cranking to see if this is your problem, but I am 100% sure JAY is correct and it is a set up problem, just needing a little more fuel etc, or a bigger prime etc.
Ecu's will work down to around 6 or 7 volts, your starter won't.
tabetha

 

I have personally put a multimeter on the front of a battery cable from the boot - under crank the battery was dropping to 10.5 volts. The front of the cable was dropping to about 8.5 volts. Therefore the cable was dropping 2 volts under load. The ecu was an autronic that stipulates voltage must be above 10.5 (or 11 - I cannot remeber) volts. The cable was 35mm square so should have been plenty enough.

Anyway - wiring the ecu directly to the boot solved the problem. I have also seen other cars drop to 8 volts under crank and still crank and i think you will find that mose ecu's want 11 volts or so.

 

Obviously a bigger cable would also have worked but 35mm square is a big cable already - simpler to wire the ecu directly.

 

Just checked to make sure I was not going crazy.

Was an old Autronic smc - 11 volts.

Just checked the new website 6 volts min, also motec 6 volts min.

 

My emerald works between 6.5 to 18 volts, most(aftermarket) will work down to 6 or 7.
tabetha

 

I'm with Gareth on this.

 

sounds like a battery comp problem

we try and set this running the car on a external power supply so you can then set fueling from 16v down to 7v

 

The loom comes ready made with a substantial power and earth cables which are connected directly to the battery as per the manual.

 

LOL. You can spot a real mapper a mile off cant you?.

Thats the ONLY way to do this map.

 

Yeah people are confusing low voltage causing the ECU to shut down causing non-start -and- what the ECU doing with the fuel/spark while the starter motor is turning.

 

yep,,,, thats something ive never done PMSL PMSL

 

im shocked lol one of the first things i bought was a variable power supply ! but i will admit it never dawned on me back then to use it for this apart from bench testing lol , bt have used on the last 3 installs

 

Having just had my memory jogged by martins post, are you on injectors with a resistor between them and the ECU by any chance?