e85 cold start problem

[stick8555]

so this an e85 2012 zl1 camaro well its been sitting over night and for about 4 hours it will send the injector ms to 33.2. it take 3 atemps to start. it runs very poor for a few seconds then it smooths out and the cranks normal after.i will post log and file.this tune was not done by me.

[GHuggins]

Multiply cranking fuel by 1.3 and see if it's any better...

We'll need build information...

[07GTS]

it may not work for all but mine on E85 likes low cranking spark about 5 deg 150rpm and ramp up slowly to idle spark at idle rpm in that table i find that if u have it ramp up it gains torque as rpm increase but if u keep it low then can struggle and having it low at 150rpm puts u in more of the compression helping it ignite, and also having the idle airflow tables dialed in properly helps alot too

[stick8555]

Thank for the info larger injectors upper pulley and a tune that is all

[stick8555]

Just so you know you both were right I had to do both of them to make the car crank on a cold start it would not crank with just one changed

[07GTS]

sometimes the "cranking VE" can help also yours is at 100 could try 85

[GHuggins]

07GTS - Like this? Seems to take longer to fire, but does fire even with very low ignition voltage...

[Lakegoat]

That's strange that these engines are so different. Here is my startup spark, starts every time almost immediately, cold, warm or hot. On E85 or 93

[07GTS]

yea GHuggins mine is like that ill attach pic below, yea Lakegoat strange how some areas can be so different to others just have to find what works best, cam choice would have a factor as to what compression it has when cranking, my startup time is about 2 sec also for the cold which may help get it all mixing before firing, just got myself 400L of 100% ethanol so ill have to see how that goes

[GHuggins]

Yeah, I'm not sure I like how long it takes to fire - about 2 to 3 seconds like you said, but it does fire no matter what the conditions may be such as spinning over very slowly... I really think mine had too little timing in it - until hpt adds the missing seconds to transfer over from cranking to idle timing table it seems to idle very low then as soon as the regular idle timing kicks in it revs up like it's supposed to... I may just have too low of timing still, but this can be a fine line between having a "hydro locking start sensation" to having a slightly long start sensation like I wound up with...

[07GTS]

i actually ended up lowering the cranking fuel and startup airflow a little also, and on E85 my wideband shows stoich or less on cold start once running which is another issue cos its not commanded but it still starts and runs fine like that so its kinda the opposite of whats recommended but once its at 35c ECT its back to commanded, yea i get that low dip for a little bit but found some added timing in idle spark to the lower rpm mid airmass (0.36 - 0.60 ) helped control a bit of that im around 23-26 deg in those areas below 800rpm still not perfect but dosnt dip as low

[stick8555]

now the zl1 i was working on is a stock cam and she fires right up after the fuel and timing was fixed . i am about to do a twin turbo 6.0 . after see all this info on e85 and seeing the power it make we are going to start on e85 and may move to meth.

[Hoff_zl1]

I'm having a Warm Statup issue. It surges so bad it will die about 90% of the time unless i hold the throttle until CL fueling kicks in. This log i didn't touch anything and it recovered. what is weird is the LTFT is pulling a lot out at startup but once it adds about 15% (LT+ST) it will run and idle great. This only happens if i let the car sit for an hour after it's fully warmed up. No issues with cold start and no issues with Hot start. easily starts in under 2 seconds. Just to show it, here is my cranking spark (stock on a 2012 zl1) I will be playing with airflow tomorrow, but any other ideas? (side forum reply question: how do i attach a log file? i only have options to embed a link, email, attach picture and attach video)

Startup spark and fuel.PNGStartup Log_Image.PNG