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View Full Version : my ka-t runing mega RICHHHH? HELP ..


ass15
08-19-2004, 05:29 PM
my car is running hella rich, has 255lph walbro, stock FPR, FMU 8:1 .....t25 turbo, stock 7psi why do you think its running so so so so so mega rich? is it the FMU ratio ? should i go like 6:1 or 5:1?? or should i get a nismo FPR? LIKE YOU GUYS are talking about, my car is a 96 240sx ....?

may be if i get rid of the FMU ? and buy a NISMO FPR and can i raise the base fuel pressure , stock is like 33psi? right? if i raise it to like 42psi ? what do you guys think?? I know the fmu set up is lame but dont' have $ right now.. will move on to sr inj. safc and z32 maf..

thx peeep

ass15
08-19-2004, 07:47 PM
well, i just removed the FMU and just had the walbro 255lph.... it ran like 7 or 8 psi, haha it ran a lot stronger now that its turboed....... but the fukkin Autometer AIR/FUEL meter didn't move at all, it stayed at the very rich level...... even without the FMU 8:1..... does that mean my fuelpump is too big (walbro255) or the air/fuel gauge is a piece of crap ? should i run the 02 lines straight from the 02 sensor ? right now i have it spliced near ECU...should i get a lower ratio fmu? should i get a 190lph walbro fuelpump , thats little lower than 255 that i have...is the air/fuel gauge by autometer a crap? thats what i heard while ago..

callin onto all the ka-t geeks out there.. help !

on a side note : theres less smoke coming out of the exhaust.... a little blk smoke comes out...thats prolly the turbo seal??

orion::S14
08-19-2004, 09:22 PM
Do not...I reply DO NOT trust a narrow band A/F gauge to tune your motor. Very stupid, quite unsafe...

Stock O2 output is only 1 volt, and not nearly accurate enough to tell you anything.

Fuel pump is not too big...a Walbro can be handled and keep stock pressure with the OEM FPR installed.

7psi from a T25 I'd bet can be run safely by a 5:1 disc...

How's it setup?

Do you have the FMU after the stock regulator, and both are connected to a vacuum/boost line?

Have you pressure tested for leaks? That sounds likely, as stock injectors would be close to maxed (probably already maxed out) at 7psi, even from a T25...

A small boost leak wil drastically change the A/F ratio...it'll make it MUCH more rich.

Pressure test with an air compressor, let us know what happens.

- Brian

ass15
08-19-2004, 10:45 PM
also when i shift for some reason the flutter sound is coming from intake filter, whatchumay call it turbo surge....my hks ssbov is not blowing off air when i shift? thats why the air goes back to turbo and i guess spins it backward....? also i put a breather on the valve cover.. am i not suppose to do that? i should have ran a tube to the fmic piping?...

thx orion

skatanic28
08-20-2004, 12:32 AM
also when i shift for some reason the flutter sound is coming from intake filter, whatchumay call it turbo surge....my hks ssbov is not blowing off air when i shift? thats why the air goes back to turbo and i guess spins it backward....? also i put a breather on the valve cover.. am i not suppose to do that? i should have ran a tube to the fmic piping?...

thx orion

is that BOV adjustable? maybe the spring is a bit too tight for the level of boost you are running. the valve cover line should go between the filter and compressor, i dont think you should let it see positive pressure.

for the richness....i would check for boost leaks first.
FMU's seem like too much of a pain in the ass to me. if you can afford it just jump on an adjustable fpr and safc if you can, i think thatll run you about 250-400. then you can at least tune it with a wideband/dyno. and dont even look for the narrowband a/f for tuning help.

SpeedMonkeyInc
08-20-2004, 01:06 AM
[QUOTE=ass15i put a breather on the valve cover.. am i not suppose to do that? i should have ran a tube to the fmic piping?...

thx orion[/QUOTE]

Take the "breather" off. I don't know why they even exsist. You need suction there to keep the crank case pressure netural. Attach a hose off the crank case to the intake before the turbo and your motor will be happy.

sxse240
08-20-2004, 07:50 AM
I think the breather is there to provide vacuum to the crankcase which assists in ring sealing and seating. Running it vacuum is a good idea, but atmosphere won't damage anything.

ass15
08-20-2004, 08:46 AM
i'll go ahead and connect a tube from valve to the intake..after maf but before the turbo..i still need to figure out the hks ssbov and any boost leaks figure out the a/f ratio thx

Maeda
08-20-2004, 11:51 AM
The HKS SSQV will NOT blow off very easily.

a few psi ain't gonna kill your turbo anyway...

Mine won't blow until about 3psi and up even at full loose. If you really want it to go off all the time, T the line off the FPR, and run it to the SSQV. Make sure it is a wide an ID vacuum line you can use without leaking, and as short a line as possible; after I did that my SSQV would go at 0psi and up.

Go to a dyno and get a checkup. a/f gauges do NOT tell you anything. The only remotely accurate one is the greddy 3 volt gauge, but even that pales in comparison to a real dyno with wideband a o2 sensor.

8_6_Fo_Life
08-20-2004, 09:11 PM
I believe you have already gotten lots of info from those before me, but I would have to also say...

Throw the FMU in the trash. There isnt a disc in the world that will make your car run right. FMUs= pig rich...its a safety net, and HORRIBLE for tuning.

Along with the FMU, throw away that AutoMeter Lite-Brite fake gauge. Splicing into a 02 will do no better, the narrowband style gauge will be only a slight estimate of whats happening inside your engine. You'd get better results with a EGT gauge then that piece of crap.

.....hey, at least you arent wicked lean :D

ass15
08-20-2004, 10:15 PM
8 6 fo life : thanks man.......

Ricer240sx
08-20-2004, 11:28 PM
u dont need anything on the breather off the valve cover, most ppl with KA-Ts jsut runa hose off them and they go to the bottom of the engine bay and are hooked to NOTHING i jsut leave mine open and dont put anything on it!!! as log as theres no nipple for it on the intake theres no reason to make one!!!