For those with KPRO D17 - Cold Cranking

[wikkaco0]

In addition to the issues with the non vtec calibrations (handful of non vtec cars have had their engines cut out at high rpm without explanation, I seem to have the only working one in Montreal now after a vtec headswap)... it appears the base calibrations for the D17 also do not work in cold weather. The issue is cold cranking when coolant temperature is about -10 degrees celcius (or 14 fahrenheit) or colder. Leave the car outside when its about -15 celcius and when I try to start the engine just turns over at a nice 180rpm but will not start, at most it will fire once then return to 180rpm. I suspect the problem pertains to the cranking injector pulse widths in relation to engine coolant temperature. This can be found in the Parameters windows under the Fuel Trim tab in Kmanager. Unfortunately it is very difficult to tune this because I have one or two attempts a day (provided the weather is cold enough) to try new values. I have set my overall cranking fuel trim to 0% and have found the correct values for -1 degree celcius and above in the Cranking base injector pulse table. They are as follows ECT in degrees C..........-31......-15....-1.....20.....41.....61.....82.....90 Injector pulse in ms........?.........?......65.....30.....20.....15 .....8.......7 I know a linear trend is belived to be ideal and I realize these values are far from linear, but they seem to work down to about -5 degrees celcius out after having left the car out for 24 hours. Anybody else have this issue or seen something like this? My car is in my garage warming up and wired to a battery charger now. This car is usually stored in winter and has had this issue since I installed the kpro. Experienced tuners, your help would be greatly appreciated. Guessing values is really starting to get time consuming.

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[bomerman19]

Yeah I have had the cold starting problem before myself it used to be really bad with my stage 2 cam and shitty tempest map. it is not so bad now only very rarely does it ever do it to me and the temp has to drop below 20 degrees F which is probably a little less than -5 degrees celcius.

It is definitely one of the harder things to tune on the car and takes a little bit of practice, especially since most tuners don't tune for cold cranking cause it can be hard to replicate the circumstances.

So here are my questions,
what size injectors are you running?
Stock cam or something different?
What was your cranking fuel trim originally set at before you started playing with it?
and what mods do you have on the car to accompany the k-pro ie IHE turbo?

I know it's a lot questions but all those things can make a big difference in the cold cranking.

[wikkaco0]

So my suspicions were right, I'm not the only person that is dealing with this. So to answer your questions I have stock D17 injectors (84000km on them, I don't drive it much). All the bolt ons... intake, header, exhaust, no catalytic converter. Right now I have a stage 2 crower n/a cam.

The calibration overall has been tuned quite well on the street. Spent quite alot of time perfecting it. So once the car is running everything is great. It's just getting it started.

Also have a PLX wideband air fuel sensor. I'm not sure if the readings are reliable during cranking because it is being powered by the cars' electrical system. I'll try and wire it up to an external DC source when I have time.

With a 100% stock complete D17A1 with kpro, I also had the same issues. Well it was worse, I wouldn't recommend anybody use a kpro on a nonvtec d17 no matter the setup.

My cranking fuel trim was originally set to what it was in the stage2 base calibration included with kmanager. I started tuning just the cranking fuel trim and came to realize that at -1 celcius, +50% trim worked very well. But at other temperatures it was less than ideal. So I looked at the injector pulse lenght in my datalogs and started editing the coolant temperature based cranking fuel table accordingly, all the while setting the overall cranking trim back to 0%.

Thanks for your input! With any luck we'll have this solved by the end of winter.

[emjay]

stage 2 turbo cam//750cc injec
kpro
-25 degrees celcius was the only time my car didn't start .. which was ON newyrs it was so cold .. i live in toronto and my car is parked outside average 3-6 hours a day and fires rite up except for newyrs night when it was out for 7 hours str8 -30deg. or more that nite with windchill

[katzenjammer84]

This might sound like a temporary solution, but it's an easy one: buy an OEM Honda block heater

Coolant/oil will always be warm on cold days.

[bomerman19]

wide bands do not usually run properly during cranking cause that is when they are cycling through the test cycle. So wide band reading's are kinda pointless for you cold cranking settings.

Also I would not bump the cranking fuel trim up to 50% most i would go is probably 20% the problem with with going that high is you dump a lot of fuel and flood the motor and then It won't start cause it's flooded.

Let me look at the different stage 2 maps that I have and see if I can come up with some better settings for you to run. umm I have a lot to do to night so I am not going to get a chance to look at my maps till late tonight or possibly tomorrow, so bear with.

[wikkaco0]

Hondatas base calibration for the d17 with crower stage 2 NA cam has a cranking fuel trim of +20%.

Assuming I wire my wideband controller to an external 12 volt DC source independant of the car, will the readings during cranking be accuriate enough to tell if I need more or less fuel? After I have heated up the sensor to operating temperature of course.

[bomerman19]

that map throws a lot of fuel at the car bump your cranking fuel trim down to 3 to 5% if you are still having trouble pm me your e-mail address and I will send you a new base map that should help you out a lot. Right the moment my guess is that you are dumping so much fuel during cranking that you can smell it.

[bomerman19]

Sent you a Special Base map should run really good forgot to mention you should get better gas mileage with this map also.

don't have internet at my house right the moment so it is taking me some time to respond sorry.

[emjay]

i have a stage 2 turbo cam and kpro and just checked with my tuner .. my cranking fuel trip is 8% which works best

[bomerman19]

yeah but what size injectors are you running?

That makes a big difference cause it really comes down to the injector pulse and the actual map.

I'm guessing you are running significantly bigger injectors then stock so your tuner probably has your injector pulse or map set real lean so it needs to have alot of extra fuel dumped to get it running. the stock stage 2 NA base map throws so much fuel at the car that it floods it almost every time in the cold. I actaully have had to go to negative percent for cold cranking on the original hondata base map

[skipbarber]

holy shit. i just posted about this over on the hondata forum. my car has been doing this since last year. I panic in the cold if i dont have someone to help me push start the car. lol. Ive been trying to figure out a solution to this problem for a long time now. let me know what you guys come up with...

[Rufus]

I never had this problem... then again, I live in Arizona.

[wikkaco0]

I'm still working on it. Nothing good to report yet...

It's been about -25 celcius here for the last week. Definately a fuel related problem though.

It's been like this for me for almost two years. Doesn't matter if the car is stock or has a built motor. Same issue persists regardless of the calibration chosen.

Anybody know how to tell if a car is flooding or lacking fuel during cranking?

[supafil25]

i read on another forum that you need to lean out the fuel for the car to start in the cold.