coryjames

i have thought it over and, its got to be the tune or lack of thats what it has to be.

jaxtcracer

you're probably right about the congealing thing... however heat affects a lot of things..

if the fuel's temperature isn't affecting it, it could be the actual temperature of the fuel/vacuum lines themselves. if they're warmer, they're more flexible and more likely to expand when the pressure is applied. when they cool down, they lose some elasticity. perhaps that loss of "give" in the lines is what causes the pressure to overwhelm it? if there's a lot of fuel in/around the fuel pump when you turn the car off because of a rich idle or w/e, then that fuel is going to get shot through the lines when the pump activates. if the lines are somewhat elastic, maybe it gets shot through the elasticity compensates a little for the pressure. maybe?

java09

yes and no. so we shall see. because when i get a tune im going to want my car a little rich anyway.

jaxtcracer

hahaha thanks for the heads up; i kind of hope you're joking. but really, even if it is the tune, we're still trying to find out WHY it happens. as in how does the tune fix the problem. specifically.

coryjames

i have thought it over and, its got to be the tune or lack of thats what it has to be.

Kydog

Java - I use NGK 2 step colder plugs and run Mobile 1 5w-20 and mobile 1 filter. Extra half quart of oil after going turbo.

Dont quote me because I am in no way positive but I believe the fuel pump has one speed and one speed only it is up to the ecu and the injectors themselves how much of that fuel/pressure they use in the line. So your thought of the build up being at the pump doesnt sound right to me.

If anything you would have left over fuel in the motor after turning the car off because your so terribly rich but that doesnt make sense either because you say this happens BEFORE you crank the motor.

Im at a loss I wish there was a cert. tech on the site.

Kydog

Also I believe the fuel pump is inside your fuel tank itself so that makes your theory sound funny. There is always fuel around and inside the pump lol. On the same note, there is always fuel in your lines its not like when you turn the car off they completely clear and in your words "gets shot" through the lines when you turn the car on. The fuel always exists in the line the pump just primes up the pressure before startup.

Mr_Meaty

well, i was thinking it was due to running rich, which a tune would fix because you would not be running rich at idle...but kinda the same way we get backfire...that kinda boom. but I can't be sure cause I don't have it.

java...i deleated that stupid video, and todd is the one under the car.

Ace83

iTrader: (6)

java i have NGK step 2 colder spark plugs like kydogs and my afrs usually are from 14.7-15.4 and 70% of the time its on 15.0- 15.1, that is lean right? it maybe true about residual but question is, Is there a spark that triggers the boom with the key just in the "ON" position?

question here, what is the ideal idle and cruising afrs? my cruising it at 14.4-15.7 and it constantly bounces some times hits 16s for like 3 secs.. im just concerned about being lean all the time

jaxtcracer

what are you AFRs at idle? that's the big question, b/c the car is always at idle for at least a few seconds before you turn it off.. and yeah 16 is really f'ing lean

Ace83

iTrader: (6)

my idle afr range is 14.7 to 15.4, most of the time its 14.9-15.2. 16 is happens occasionally while cruising for like 2-3 secs but afrs cruising it 14.4 -15.7.. how's yours?

java09

mine only heads down like that when i let off the throttle as the throttle bottle is closing and should bottom out and you should read --.. but ace i have the smae thing with you at idle.. pig rich one second and the next its a little lean then the next its right on at 14.7..

Mr_Meaty

no, the real question is what are your AFRS while in boost.
going a little lean at idle or cruizing for a little while aint to bad as long as it's USUALLY around 14.7, but if your over 13.5 when in boost...BOOM!

coryjames

so where are ideal afr at idle partial and full?

java09

idle 14.7, partial you want it to flow smoothly from 14.7 to 10.5-11.5 around there for WOT.

Mr_Meaty

ehh...14.7 it idle for sure...I'd say partial around 12.5 and WOT around 11.5...depending on how much PSI your running.

java09

basically what i said.

Kydog

Meaty is closest in numbers but partial does not have to be that rich. I run 14.4-15 all day partial throttle on the freeway. I also run 11.8 up top.

Java - U didnt say the same thing as you said partial throttle should hit 10.5 at some point. LOL You should never hit lower 10's thats way too rich. Also just so you know if you ever see 10.0 than your tune is far too rich because the uego doesnt register anything lower, time for a re-tune or check for boost leaks!

The "boom" cant be u guys running rich than because my idle afr is 13.4 so I run way richer than you guys with no problem. In case your wondering why my idle is so rich is because my tuner tuned it that way to try and help the stalling issue.

Ace83

iTrader: (6)

so a lean idle and cruising isnt that bad for the engine let say afrs of 14.9.15.5? anyone knows what afrs in idle and cruise are the oem/na the tc has?

java09

what i meant to say was idle 14.7 and smoothly to 10.5-11.5 at WOT.. i just worded it funny. my bad tunning expert..