Honda / Acura K20a K24a Engine Forum banner

1 - 20 of 39 Posts

·
Registered
Joined
·
48 Posts
Discussion Starter #1 (Edited)
I'm posting this not because people asked for it, but because it took me weeks to figure out why the hell I couldn't get my car to start when the temperature dropped below 50 degrees. I figure if anyone else runs into this problem in the future, hopefully they'll search and find an answer here.

First off, there's so much bad info out there on E85. When I was looking for information about starting on E85 in cold climates, the vast majority of people claimed that you had to simply increase your injector pulse-width while cranking by 30% which is absolutely false. I tried this and it just left me scratching my head as to why my car wouldn't start nicely.

In doing some more searching, I stumbled upon an SAE paper specifically studying cold starts using E85. They said:

SAE said:
"To keep the same engine startability as the gasoline in a cold environment by using the E85 fuel (ASTM Class-3), about 3 times the quantity of fuel should be injected or RVP of E85 fuel should be adjusted to about 108 kPa."
I forget what engine this quote was referencing, but the point is that this was a good starting point for me, and here's what ultimately ended up working.

Open the Hondata software and navigate to the "Fuel Trim" section under parameters. You'll see a table towards the bottom that is injector pulse-width versus engine coolant temperature. The stock table looks like this:


So in order to get the engine cranking properly we need to increase fuel by roughly 3-times. HOWEVER, if you have larger than stock injectors you have to take this into account! The Hondata software only asks for pulse-width, so if you double the size of your injectors and leave the pulse-width alone, you'll get roughly twice the amount of fuel relative to the stock injectors. Let's work through an example.

I have 650cc injectors, and stock was 310cc. That means my injectors are already 2.1 times larger than stock, but we need 3 times the flow. So, we still need to increase our cranking pulse-width by at least 1.5. So looking at our stock chart, we need to multiply all of the pulse-width values by 1.5. Note: You cannot adjust the pulse-width higher than 255ms! This is an inherent limit of the engine computer.

It took some experimenting, but I finally got my car starting nicely in cold weather. It dropped down to about 30* last night and my engine still fired right up. I should note however that I required more than 3-times the stock cranking values in some of the colder regions of the table, and less than 3-times in the warmer regions. My cranking pulse-width chart is as follows:


I should also note that I've altered the temperature range for two reasons. First, amazingly, I'm out of injector below about 25 degrees! I don't think my car will start at temps lower than 25*, but the other reason why I changed it is because it never drops to -24* here in MD, so changing the scale increased resolution, and also eliminated useless temperature values.

Hopefully this helps people switching over to E85 in cold climates :dance:

*Note - I don't know exactly what concentration of ethanol I'm running. I'm not sure if the stations around here have switched over to a winter blend yet as of this posting, which will affect how much pulse-width you need to start when the engine is cold.
 

·
Registered
Joined
·
48 Posts
Discussion Starter #3
Do you have any problems starting when you run gas? In warm weather? I guess what I'm after is whether you've ruled out a hardware problem.

Either way, attach your tune to your post and I'll be happy to give it a look. Also list your injector size for me if you would.
 

·
Registered
Joined
·
147 Posts
The problem only occurs in colder weather. For instance it is EXTREMELY hot during the summers down here in Texas. During the summer time I have no problem starting the car, usually turns over/cranks in about two turns. Winter time is when I have my problems. What I tend to do in the winter for "easier" (if you even want to call it easier, because its still a pain in the ass) Is ill turn the key on to prime the fuel pump (stock pump) crank the car about 6-10 times. Turn the key back to off then turn it to "on" again to prime the pump. Usually the car will start withing 6-10 more cranks.

My motor setup/fuel system is as follows

k20a2 motor
kpro tuned on e85
800cc DeatschWerks Injectors
still running stock fuel pump
 

Attachments

·
Registered
Joined
·
48 Posts
Discussion Starter #8
Alright, so in looking at your tune I think if we just up those injector pulse-width versus coolant temp values you should be good to go.

Since too much fuel can be as bad (or worse) than not enough, I started upping the values in the colder temps somewhat conservatively (see attachments). This should help a lot, but let me know what temperature you're in (or really, just what your coolant temp is) and how the car is behaving and we'll refine the numbers a bit.

BTW - I was going to name the tune "_jordan_edited" but I realized you already used Jordan in the title. That doesn't happen to me very often =p
 

Attachments

·
Registered
Joined
·
147 Posts
Alright, so in looking at your tune I think if we just up those injector pulse-width versus coolant temp values you should be good to go.

Since too much fuel can be as bad (or worse) than not enough, I started upping the values in the colder temps somewhat conservatively (see attachments). This should help a lot, but let me know what temperature you're in (or really, just what your coolant temp is) and how the car is behaving and we'll refine the numbers a bit.

BTW - I was going to name the tune "_jordan_edited" but I realized you already used Jordan in the title. That doesn't happen to me very often =p

Thank you so much. I will check these out when I have some downtime. Been really busy with work lately.
 

·
Registered
Joined
·
147 Posts
Update: I have the worse luck lmao. battery took a shit in my laptop so I am unable to get out to the car. Either going to use an extension cord or borrow a friends laptop. I'll let you guys know the outcome. Stay tuned
 

·
Premium Member
Joined
·
1,086 Posts
I would like to add that this also worked for me. I live in CT and needless to say we see harsh winters and very cold temperatures. My recently completed race car has developed this same very difficult cold start situation. I also tried raising my cranking fuel trim and that did not seem to help.

I run ID1000's at 62psi and use E98 fuel. My high compression motor would kill the battery trying to start the car traditionally. Had to use starting fluid on a few occasions or jump off another car and crank the car for an EXCESSIVE amount of time to the point I started worrying about my New Honda starters health, lol.

Stubbled upon this thread today while roaming and decided to try it out myself. Surprisingly enough, it works! Changed the values in the colder temp tables, uploaded the map and the car started within about 4 revolutions of the motor which is about 1-2mins earlier than before, lol.

This should definitely be stickied or adding to the FAQ page.
 

·
Registered
Joined
·
147 Posts
I would like to add that this also worked for me. I live in CT and needless to say we see harsh winters and very cold temperatures. My recently completed race car has developed this same very difficult cold start situation. I also tried raising my cranking fuel trim and that did not seem to help.

I run ID1000's at 62psi and use E98 fuel. My high compression motor would kill the battery trying to start the car traditionally. Had to use starting fluid on a few occasions or jump off another car and crank the car for an EXCESSIVE amount of time to the point I started worrying about my New Honda starters health, lol.

Stubbled upon this thread today while roaming and decided to try it out myself. Surprisingly enough, it works! Changed the values in the colder temp tables, uploaded the map and the car started within about 4 revolutions of the motor which is about 1-2mins earlier than before, lol.

This should definitely be stickied or adding to the FAQ page.

Awesome! Glad to see it solved your problem. Can't wait to mess around with mine!
 

·
Registered
Joined
·
48 Posts
Discussion Starter #16
Hell yeah! Man, it's really gratifying to hear that this actually helped people. Thanks so much for coming back and confirming that it worked!
 

·
Registered
Joined
·
147 Posts
IT FIXED MY PROBLEM!!!!!!!!! OMFG I want to fly to where ever you live and give you a hug (no homo). Seriously, I was about jumping up and down in the seat when the car started. Man oh man, I can't thank you enough! I've had my motor swap for four years and have had the e85 tune on it for three of those years. Three years of headaches when the colder season would near. Thank you so very much, someone really needs to contact a admin and have this thread stickied. I'm not surprise it isn't already.:)
 

·
Registered
Joined
·
48 Posts
Discussion Starter #18
Dude, I appreciate the hell outta you coming back and saying thanks! It's easy to forget on the internet that there is actually someone on the other end of that computer.

I basically just hammered those values home so they could probably use some tweaking. What I like to do is bring the pulse-widths down as low as I can and still get the car to start reliably. You can see what I'm doing in that table so you can either experiment yourself, or just leave it as it is. But you may find as the weather keeps changing there are some temps you still have trouble starting in. If you can't figure it out don't hesitate to hit me up.

Thanks again for coming back to me let me know it worked for you man :new_slayer:
 

·
Registered
Joined
·
147 Posts
Dude, I appreciate the hell outta you coming back and saying thanks! It's easy to forget on the internet that there is actually someone on the other end of that computer.

I basically just hammered those values home so they could probably use some tweaking. What I like to do is bring the pulse-widths down as low as I can and still get the car to start reliably. You can see what I'm doing in that table so you can either experiment yourself, or just leave it as it is. But you may find as the weather keeps changing there are some temps you still have trouble starting in. If you can't figure it out don't hesitate to hit me up.

Thanks again for coming back to me let me know it worked for you man :new_slayer:
No problem bro! Again, I appreciate your help! This is going to help so many people on E85!!!!
 

·
Registered
Joined
·
48 Posts
No problem bro! Again, I appreciate your help! This is going to help so many people on E85!!!!
sup ppl im just changed my car to e85, my temps arent as cold as you guys cause im in los angeles. so is it safe for me to upload a map with the exact numbers u put in your car? let me kno i was gonna try it now. My car starts but when its cold it only takes about three times as long then a normal car would so about 5 secs with the key turned all the way.
 
1 - 20 of 39 Posts
Top