My '09 Fit has a slight stumble before the motor catches when cranking for the very first time each day. All starts after that, hot or cold, it fires instantly and reliably after exactly 2 revolutions, without the stumble. Maybe the engine is just extremely lean-burn sensitive and this is normal behavior........but how come only the first time each day?

Before cranking I switch the key on, then wait for the fuel pump pressurize the fuel rail before cranking it. The motor spins over about 2 revolutions and then fires. It sounds like it doesn't get enough fuel on the first ignition cycle and if I release the key it stumbles for a second then runs fine. I can drive away immediately with full power if I want, but I always take it easy. The blue cold temp light goes out in less than 1 minute. Drivability is perfect, never misses or idles rough. Just a quirk that seems odd to me.

 

let the starter motor work longer before the engine turns over. no issue. that's still considered normal on most cars including my GE.

 

Yeah, my '11 does the exact same thing. I almost feel like I need to blip the throttle or something. I've learned to ignore it.

 

Can it be something possibly to do with the "fuel trims" that I've heard of, being not set up right for cold starting conditions? Surely the car is able to sense basic parameters for a cold start such as air temp/humidity, fuel pressure etc to accomplish such a basic task. Haven't done my LMS recall yet, next oil change. I do have some ticking, but it's more noticeable at higher rpms cruising around town. Not bad, but audible

 

I think something to do with ULEV controls and parameters for cold starts. Less raw fuel is blown out the back. But yes, it does seem to have an awkward start. A lot of times I have to give it a second crank after thinking it's caught. Nature of the beast.

<gratuitous swipe at premium fuel acolytes>If you're running premium fuel, try regular. It starts easier.</swipe>

 

Nice try Steve, Its the change in fuel trims, temps and barometric pressure changes plus ethanol puddling . Mostly ethanol because it wont burn until the engine temps are almost warmed up and puddles in the engine, That's why they use it because it just passes through the exhaust as ethanol which does not pollute.

 

In other words: you haven't the slightest idea.

puddling.

p.s. ethanol burns.

 

Spelling was not my major and I know more about fuels and engines then you with your bad manners.

Ethanol vaporizes at 172 degrees which is not the temperature at start up with a cold motor. 10 percent ethanol is a lot if that is all that is in the injectors and fuel line due to heat soak when you shut the motor off. Ethanol cools so it wont vaporize in cold combustion chamber so it puddles and puts out the fire.

 

I didn't know ethanol burned, thanks for clearing that up Steve.


I had the same hesitation for a few months. For the past month I have had no hesitation and coincidently I have not had that ethanol smell during warm up. I think the ethanol is the contributing factor to the hesitant starts and has nothing to do with the grade of gas.


I RUN 93 OCTANE!!!

 

You're absolutely correct. And you didn't spell puddling wrong; I just never heard it used in a context other than raising puppies.

Now fill us in on fuel trims, atmospheric pressure, and temps. Where puddling isn't involved. In a Honda Fit.

Please apply both to the Fit's hesitation to start compared to other cars running the same fuel that don't hesitate. And describe the mechanism for Fits that hesitate to start when no ethanol is present.

And please correlate this with ULEV engines. Is it possible tad slow starting has nothing to do with ethanol?

And if you would, please tell us what characteristic of premium gasoline might make it less likely to ignite.

Kirinzon, what makes you think premium doesn't have ethanol? You may be right, but in this area all gasoline has it.

 

Google cold start stumble and you will find every car has that problem going back past ULEV. I had a tiny problem today in the morning but it ran on first crank but stumbled. By adding ethanol they lowered the pollution at start up by a few million cars.

Fuel trims are set in the Random Access Memory which help the car run because of changing conditions. The fueling needs are different when cold and there is a enrichment correction maps the ecu uses but it starts form the lean side to prevent hydro lock. What I said about ethanol, I still stand behind it. Ethanol starts vaporizing after heat is produced by the light ends of the fuel being burned. Both premium and regular has light ends to get the process started. Bp premium is ethanol free, my fuel trims are in the negative (-3.1/-9.6 long term) which mean fuel is being pulled. Wife's car using E10 regular and getting 26mpg are 0. My car fuel trims this week are -5.5 for both and getting 43 mpg. Same type of car.

 

I'm afraid you're wrong on the evaporation temperature of ethanol. 172 degrees Fahrenheit is when it boils.

Gasoline boils anywhere between 100 and 400 degrees Fahrenheit. (cite)

Neither of which has anything to do with evaporation. Or atomization. If it did, Gasoline might be less likely to evaporate.

I think what you're grasping at is Reid Vapor Pressure. Ethanol has a higher RVP leading me to think that you are wrong. Again (and I was too quick to agree with you). "Ethanol, reduces T50, but not DI, and its impact on RVP will lead to higher evaporative emissions" (cite page 18). By raising RVP ethanol in fact helps cold starts, but may lead to a greater incidence vapor lock in hot engines.

BP premium fuel is not ethanol free in my area. Not sure about yours. Illinois looks like pretty slim pickin's where E0 fuel is concerned. PA too.

Which leaves me pretty much with, you haven't the slightest idea what you're talking about. Please try again.

 

My 2010 MT does the same thing some of the time but only on the first start of the day.
It's been discussed before and it's been tried to be related to a few things [as is going on here].

Bottom line for me, I crank the engine the same each time I start it.
If it doesn't 'catch' on a 'cold' start the first try it always does on the second. Never have the issue other than the first start of the day - and it's not that often.

I don't think it necessarily indicates a problem, but if it creeps in on every start or becomes increasingly difficult it could be pointing to a: 1) Fuel filter, 2) Fuel pump, 3) Faulty injectors - in that order, however, I wouldn't worry.

K_C_

 

My car was doing this on the late spring/early summer batches of gas around here. It is completely fine. On the days after I filled up with E10 out of convenience, I could expect the crank to spin as much as 7-8 times before catching.

This is a good post:

Also:
Steve talking about anything fuel or ECU related is like me trying to give tips on feng shui.

Which is precisely why I put him on ignore and I recommend any FF members curious to learn something worthwhile listen to SB over him on any given day.

Nowhere does SB pretend to be an english major and after a 12+ hour day of actually working his ass off a few slips here and there can be forgiven.

Additionally, there is E0 right around the corner from my house.

Now back on topic. This has absolutely nothing to do with ULEV and more to do with the ECU dicking around with the Coolant Temp Fuel Enrichment tables (that have been around since the late 80's, think OBD0) because of the ridiculous variety of fuels on the market and their myriad constituents.

What said table may look like in an OBD1 Vehicle:



If you have ever tried to start a car running E20-E98 (or any alcohol for that matter) engine in the winter that is not at the very minimum a 10:1CR or greater (most are considerably lower, even today) you fully understand how laughably stupid this statement is by our resident shit-talker Steve:
"By raising RVP ethanol in fact helps cold starts"

Any appreciable amount of alcohol makes it so tough to fire and stay lit that in many cases I have had to adjust the Fast Idle Air Valve and remove phenolic spacers to speed the rate at which the throttle body/intake manifold material heats up.

There are even OE manifolds that come with coolant provisions in them in anticipation of the potential adoption of E15 fuels. Because they aid in atomization and help evaporate the small puddles that build up when fuel is not carried away by the air stream through the ports and condenses on the walls of the runners/bowls so it doesn't gather in liquid form on top of the valve hats and really start to fuck up your exhaust gas oxygen readings... It also makes the engine more consistent from cylinder to cylinder.

Barring inherent cylinder filling/evacuating issues due to manifold design on either end, reversion from the cam (duration/lobe seperation angle) and backpressure, etc. Some honda motors are known for #3 cylinder getting the shaft in terms of fuel/air mixture. Which is one of the reasons I would be hesitant to buy something like a weapon-r china manifold.

Fuel Trims, Long Term and Short have no bearing on cold start because until your O2 sensor(s) start to cycle you will be in Open Loop operation.

You should stick to stuff you have actual experience with and leave complex technical matters to the people who do this stuff daily.

I mean do I come to your job and smack the broom out of your hand?

 

These are the seperate tables for idle air clamping for whether or not the A/C compressor is engaged (load dependent, in MAF Hz) and the idle specific coolant temp adjust tables (currently setup for gasoline)


This is what the EGR Solenoid Parameters look like, this is not as you can see the factory settings because my EGR is actually blocked off and these are the settings I use to control my meth kit when it is on the car. The EGR can be used to help here too, but that is a conversation for a different day.

 

Set it straight DSM... Hey, nice Avatar! I likes...

 

Also as far as my Ethanol "street cred" heres a 33psi pull on E85 running a bit rich with relatively low timing (high comp motor)This is a 2.0L with a 60mm turbo:


MAFComp table still needed tweaking so my FuelFlow and Airflow are logged way less than what was actually going through the motor. You can tell because my FrontO2 is dying and showing pig rich, which conflicts with the Wideband. I was moving about 66lbs/min airflow on this log with 13* timing up top, Wideband was showing 11.5:1AFR (Gas Scale), so Lambda of ~0.78 or E85 AFR of 7.8:1. So leaving a lot of power on the table for the sake of reliability.

 

i have no idea what r we talking about here... all i know is i turn the key, i hear: krrnnggkk... ngkk.. ngkkk.... vrooommmm.... and i'm good to go... and it will be a bad day, if i hear.. krrnnggkk.. nggkkk... ngkkkk.. ngkkkk... crraaaccckkk......

that's the best of my techincal knowledge so far...

ps... it seems spelling is not my good traits either...

 

Ahhh, so Bullet had absolutely no idea what he was talking about. Thanks for your backing me up and your polite timely response.

E0 is right around the corner? You buy Phillips or no name gas? Because it sure looks like BP doesn't distribute it in IL outside of Savanna.

 

Thank goodness your wrong or else you would explode after drinking. Vaporization - Wikipedia, the free encyclopedia