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Jenno007

Warm Start Struggles

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I keep removing fuel and it starts a little bit easier each time - here is less crank enrichment - https://ufile.io/7zokj

 

Still doesnt make sense as it will fire up perfectly fine no matter the fuel settings if I turn it off - wait 10 seconds and start it again

 

This only occurs if I leave it for 5 minutes or more. 

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Im starting to wonder if you have leaky injectors, most fuel systems hold pressure in the rail for a few minutes after shut off so this could be flooding the engine?

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Hmm yes that could explain it, although they are relatively new ID2000 so I'd be a bit upset if they were leaking given I bought what I thought were some of the best injectors. I guess remove all crank enrichment and add heaps of air could help combat this?

 

edit: obviously the solution would be to replace the injector but this would help prove the theory before spending a few hundred $ on new injectors

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So I've done some more research and this seems to be a common problem with e85. People with a variety of cars are having trouble starting with warm e85 no matter what they do with the fuel. 

 

Seems the best fix is more air when cranking, could someone please advise the best way to add more air when it's cranking, but then I don't want it to rev too high when it finally starts? 

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You can check to see if the injectors are leaking by running the pump with the fuel rail removed from the engine. Make sure the injectors are secured so they dont pop out. If you see fuel seepage around the outlets then you have a leakage issue.

You could manually give the engine more air by holding the throttle at 10% while cranking, if that improves things then your on the right track

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I will try remove the fuel rail and see if the injectors are leaking. The cars running a 1.8t 20v audi/vw engine bored and stroked to 2l. 

 

Would holding the throttle increase fuel while the car is cranking? 

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If your main fuel tables load axis is set as TPS then it might otherwise under cranking conditions the engine will pull very little vacuum, so will be basically be reading off the 0 - 500rpm cells around 100kpa (0kpa mgp)

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Some people have had success changing the injection angle for cranking to earlier in the cycle for E85 so that it is in suspension rather than hitting the back of the valve.

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I had a similar issue. Couldn’t sort it out. Running a truck battery jumped  helped which made me think the dead time vs voltage was off. But I feel that may be related to better spark to ignite the mixture  

The thing that fixed it completely was removing my Xspurt 1000cc injectors which had the dispersion disc machined off like other high flow injectors (ID,etc) and replacing with Bosch 3/4 long nose 980cc injectors. These have a proper dispersion cap (7 hole maybe) rather than the garden hose single outlet. 

All my problems went away. Black smoke disappeared, starting problems were non existent  Car felt OEM again and picked up some fuel economy and power.  

Picked up the problem by filming the injector firing at cranking on a high speed camera. 

The Xspurt injector would hit the valve/port and stick to it mostly,  the Bosch would hit it and bouch back in a mist Ball night and day difference.

The Amount of post injection Tau(wall wetting) is very obvious with less than desired atomization. 

May not be your problem but though it worth mentioning my experience 

Matt

 

 

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