Author Topic: Higher EGT and increased consumption after FW upgrade.  (Read 6545 times)

Offline tweak

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Higher EGT and increased consumption after FW upgrade.
« on: April 25, 2011, 11:05:11 pm »
After the upgrade from 1.1.27 to 1.1.87 i got a more responsive engine, but a higher EGT, about 50 to 100° C more at cruise loads.
The ignition should not be changed. I actually tried with over advanced ignition without seeing much change in EGT so i think that should be outruled.
It looks like the only thing changed is the injection strategy. With the new feature injector tirm, the end of delivery is now set to 280-350° at cruising RPM and from 350° increasing upto 570° at 6400 rpm.

As i understand the previous firmware always had end of delivery around 720° ? This would mean a early delivery on closed valve, while i'm now delivering on just before open valve on cruise RPM and on open valve on high rpm. (Inletvalve opens at 354°)
I then tried to set the end of delivery earlier to about 220° but the engine did not like this and fuelling had to be increased to get a stable running.

The consumption has also increased, so the only thing i figure is that more poorly burned fuel is entering the exhaust port. But lambda readings has also not changed so i'm a bit puzzled over this. Could it still be the ignition?

Offline tweak

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Re: Higher EGT and increased consumption after FW upgrade.
« Reply #1 on: November 06, 2011, 11:05:18 am »
The problem with higher EGT's solved after upping the ignition about 10° at cruise and non boosted loads.  Consumption figures still have to be checked.

Offline rob@vems.co.uk

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Re: Higher EGT and increased consumption after FW upgrade.
« Reply #2 on: November 06, 2011, 07:44:05 pm »
Did you check the timing before advancing?  There might be something to do with the triggering that has changed...

Rob

Offline tweak

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Re: Higher EGT and increased consumption after FW upgrade.
« Reply #3 on: November 07, 2011, 10:19:36 pm »
Rob, yes I will certainly do that next time i visit my workshop. Unfortunately i do not have equipment for checking timing on COP's. However i see the primary trigger is unchanged from previous FW.
Is there any particular reason to believe it's been changed during FW upgrade?

Another thing, i think it would be interesting for quite a few of us VEMS users to see a VAG factory timing table for this engines, at least at non boosted load. I know it's been requests out there already but haven't seen any replies to this yet.

Offline rob@vems.co.uk

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Re: Higher EGT and increased consumption after FW upgrade.
« Reply #4 on: November 08, 2011, 08:49:44 am »
I'm anal about ignition timing so I always make sure, just in case... For COPs I have an old HT lead that I use between the coil and the plug, the spark wont be brilliant but it allows the light to hook-up easily enough.

If anyone knows where the factory timing tables are published then that would be the only way I could think of that information being disseminated, I don't know of anyone in the VEMS team who's hacked a stock map.