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Warm Start Struggles


Jenno007

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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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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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  • 2 weeks later...

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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  • 2 years later...

Hey Jenno007

Curious how you went with this?

I have gc8 wrx, walbro 255 pump, 555cc injectors, TMIC. Running 98 fuel

Cold start is perfect - first crank.

Hot start within 5 mins - starts fine

Once it sits and heat soak takes effect, cranking will be several seconds until it eventually sputters into a low rpm and slowly rises to idle.

If I pump throttle it would start but go into a fluctuating idle with overrun fuel cut sometimes cycling on and off.

Been like this since I got the car 18months ago.

I've been applying 10% throttle until it starts to get around the problem. Usually takes 2-3 seconds-ish. (A bit embarrassing sometimes but I've learnt to live with it)

Tried 3D pre-crank prime, startup step increase and IAT fuel trim increase @0% TPS .. but couldnt seem to get any improvement to determine whether I was on the right path.

Also, I can't open your images on the first page, can I ask how you are apply increase in throttle opening? Is that by increasing startup step?

I'm playing with 3D crank enrichment at the moment and it seemed to help. I'll leave this 3D table and see how it goes over the next few days.

Tim

Cold start 27dec.PNG

warm start 27dec.PNG

warm star with 3d crank enrich 27Dec.PNG

Ign Table 1.PNG

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So in the above table I took the original cranking enrichment values as the 'base' value I guess you'd call it, and then added for high IAT temps... Didn't work very good. Looks like it's only using the 40% figure across all ECT temps. So I'm looking at my first 3D crank enrichment trial as a success - because now I know what not to do :)

This is my new 3D crank enrichment table which is definitely an improvement compared to without the 3d table. I can start it without 10% throttle during crank, at high IAT temps - from heat soak. I also changed Startup Step values from 15 across the board by stepping each increment of 10% ECT by 5 steps.

 

3d crank table.PNG

startup steps.PNG

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I too am battling the dreaded "heat soak" start problem.

To the point that if I need to stop before getting home I take another car.

I am using a mechanical fuel pump on the RB with surge tank in the engine bay supplied by the in tank lift pump.

Up to now I have put the blame squarely on the mech pump and fuel boil off within the rail. It gets bloody hot !

Data logs however show fuel pressure at hot cranking so it should start.

Is there a way of increasing ign. on prime beyond 5 seconds ? Thunder ecu.

Thanks for the added feedback here, will play in this direction and see..

*I have new respect for the std RB starter motor !! *

 

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