boosting but should pull harder

Mx6lsT · Post by **Mx6lsT** » January 12th, 2005, 10:30 am

Ok, just got the car boosting to 5psi. I'm a 2.5v6 running 12:1 FMU Dual feed kit, stock injectors walbro 255hp all the fuel mods except much bigger injectors.

I punch the gas and the car goes but i'm seeing all richness but if i slowely work my way up to boost the car pulls like mad (pretty much not going WOT). I also have stock exhaust no cat.

pictures can be seen at http://www.tylerman.net/carstuff
my car is the red car not the green one on there.

DavidOS · Post by **DavidOS** » January 12th, 2005, 11:58 pm

wot, probably having problems with air/fuel mix with boost probably not sparking or igniting properly.

babyblueMX3 · Post by **babyblueMX3** » January 13th, 2005, 10:03 am

yeah that's what I was thinking too...you're running mad rich when you step on the gas and when boost is building up you're leaning it out making it faster. I think 12:1 fmu is too much. You got a Vortech ?

Mx6lsT · Post by **Mx6lsT** » January 13th, 2005, 12:04 pm

yea I got the vortech I was thinking of stepping down to the 8:1 or the 10:1

I'm going to pull a couple plugs today see how things look

I also noticed that when I start out say cold
let it warm up for 3 minutes or less
then drive and punch it , it will pull like mad then as the car warms up it gets slower and boggy like something is choking it also I think my back pressure is so high that say i'm in second and i'm around 1800 rpms and I punch it the car wants to die as in ... if you try to start from a stop in 2nd gear.

Edit: Pulled #'s 2 4 6 right on the front bank I think that 2 4 6
any how 2 was brown 4 was brown 6 was jet black

papa roached · Post by **papa roached** » January 13th, 2005, 12:33 pm

id step down to the 10:1, most turboed PGTs i seen run 10:1

Mx6lsT · Post by **Mx6lsT** » January 13th, 2005, 12:36 pm

6 is so black it almost looks fouled

Mx6lsT · Post by **Mx6lsT** » January 13th, 2005, 11:47 pm

http://www.tylerman.net/gallery/carstuff/1_3_5
http://www.tylerman.net/gallery/carstuff/2_4_6

pictures of the plugs seems like 6 is the problem

oil rings = bad ..... to fix = rebuild

oh well at least I will have a bullet proof block then

JWMotorsports · Post by **JWMotorsports** » January 14th, 2005, 10:23 pm

plugs 3 & 5 show signs of detination also (the small specs around the electrode and insulator)

What heat range plugs did you get? stock, colder, hotter?

That can be caused by running overly rich as well as to lean. Your case sounds like it's to rich which caused the problem. Running way rich increases the EGT's really high and causes the plugs and combustion chamber to get so hot they cause preignition (detination). Since your car is turbo'd you should probably run around 12.5:1 Air/Fuel ration (AFR) with EGT's around 1400-1500*F at WOT. Most Narrow Band O2 sensors can't read richer than 12:1 AFR. If you have a Auto Meter A/F Gauge tune it so it is a few bars (around 3) into the rich side at WOT. At idle and crusing (not accelerating) the bars should bounce around the stoich (14.7:1 AFR range). It doesn't hurt for it to bounce stoich to lean at idle. While tuning make sure you listen for detination (knock), it sounds like loose chang in your pocket or little pieces of tin ratteling around in your engine bay. If you hear it IMMEDIATLY let off the throttle. You may need to retard the timeing a hair in this case. If you only hear it at high speeds you may be able to tame it with a tad more fuel.

DavidOS · Post by **DavidOS** » January 14th, 2005, 11:34 pm

and get some new plugs

Josh · Post by **Josh** » January 15th, 2005, 2:18 pm

i had a similar problem, i had to re time my cams. im running them one tooth off advanced. and it runns like a bat out of hell. but in the stock position it runs much like what you say yours is. i also had to notch out the distributor so i could advance it a little more. but its mostly from the cams im running.

Mx6lsT · Post by **Mx6lsT** » January 17th, 2005, 1:08 pm

I'm one step colder on the plugs than stock
I hear no knocking or the loose change that you speak of
normall the car feels like its gonna die though if i go below 2krpms and try to accelerate, probably from the stock exhaust all the backpressure

ok over the weekend new plugs gapped at .030
adjusted the base fuel pressure
tied vris open
installed boost controller
checked compression -all ok

got the car to pull consistantly better but I feel like it should be better

so i decided i'm picking up a megasquirt 370 cc injectors and modded rails

and just run 10 psi (used moderatly of course)
i'm also putting in a 3 inch exhaust in feb. then I think this car should tear the streets up

Mx6lsT · Post by **Mx6lsT** » January 25th, 2005, 1:11 pm

well I figured out the sporadic boosting

now when I first start the car let it warm up for say 10 mins then go drive

if I punch it it goes.. .only 5psi but holy s---...1st 2nd 3rd vrooom

but then as the car warms up the kick goes away ... feels like my power band moves from 3500- 7000 all the way back to 3500 to 4200 area and thats it

I have stock exhaust
but why is it when my car first starts up it pulls like mad but then after its been running for awhile bleh no more power