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Cold start problems
piddy - 23/7/14 at 02:02 PM

Hello all.

I’m running a 2.0 Ford Zetec blacktop fitted with 45mm Jenvey T Bods with Omex 600 ECU.
I’ve found that when I try to start from cold it doesn’t like to start. It seems to me that she fires on two cylinders and then three and then four after a bit of accelerator pedal.
Once it’s fired on all four cylinders and revved a bit it runs fine and will start again no problem even after ½ hour.
I’ve been in contact with Omex and this was their reply.

A cold engine requires more air and fuel; this is why idle control valves are used. Your throttle body set up does not have an ICV and therefore requires you to open/blip the throttle slightly when starting and warming up. If you partially want to start the engine from cold without any throttle then you could try setting the throttles so the cylinders consume 5.5kg/h possibly 6kg/h, this should give a good start up when the engine is cold, but when the engine is hot you may find the ECU will struggle to keep the engine speed down to its target idle speed.

I’m running 5 Kg/h
When I was running Megasquirt on my last engine, there was a cold start page which once set up the car started easily. Is there a similar page on the Omex system?
Have other experienced starting problems using the Omex 600?
Any help greatly received.


blakep82 - 23/7/14 at 02:12 PM

Not used omex, but a quick google, and look at page 39/40 gives instructions on coolant temp corrections?
omextechnology.co.uk/600%20ECU%20Tuning%20Manual%203v00.pdf


Paul Turner - 23/7/14 at 02:29 PM

Not OMEX on mine, use MBE and Jenveys on a standard 2 litre Blacktop.

No ICV on mine, it is possible to fit one but complicates the installation, never seen anyone do it.

In the MBE software there is a water temperature correction map. It simply richens the fuel mixture by the percentage in the map.

It does make a difference. When I did some work on mine this winter I forgot to reconnect the water temp sensor. On start up it coughed and farted knew there was something wrong. Switched off and a quick look round spotted the connection off. Refitted it and it started perfectly.

Sure my TB's are set to draw about 4.5 kg/hr.

After a cold start the engine does idle a bit slow (sometimes needs blipping in spring/autumn when its a bit cooler) but once warmed up it idles fine at about 900 rpm, exactly the same when stinking hot.


piddy - 23/7/14 at 02:29 PM

Thanks I'll take a look.


daveb666 - 23/7/14 at 02:32 PM

My zetec on TBs has started from temperatures as low as -10 and idles perfectly. I left it with my mappers (Noble MOtorsport) and they just tweaked the cold-start compensation maps each morning to get it spot on.

If your engine hasn't been mapped properly you'll be missing out on a whole heap of bhp and torque


Jed - 23/7/14 at 08:03 PM

Don't overlook the simple things like the correct spark plug gaps..... says the guy who was struggling with cold starting only to discover that the gaps on the plugs were 30% less than they should have been.


piddy - 24/7/14 at 02:38 PM

Thanks Jed. spark plugs were checked.


britishtrident - 24/7/14 at 04:38 PM

quote:
Originally posted by Jed
Don't overlook the simple things like the correct spark plug gaps..... says the guy who was struggling with cold starting only to discover that the gaps on the plugs were 30% less than they should have been.



The standard gaps used on Zetecs and a lot of other recent engines are ridiculously wide as a result the HT voltage demanded is excessive, setting the gaps narrower helps avoid problems with coil packs and other HT insulation breakdown problems.