i have a mkIII 1989, hi recently put a 76mm exhaust line,85mm mufler,hks super mega flow air intake,blow off valve,forge manual boost controler and an apexi super afc II... and some times my car is failing when i push hard in 2nd gear or in 3rd gear but sometimes its ok but in other times it fails and lights the injection light.. hi also have a bost cut sensor "i think that's the name"...help me please

This message has been edited. Last edited by: hugo marques,

it sounds to me like you're still hitting fuel cut. you have a fuel cut defenser? make sure you're tuning the car right, because if you run lean, you could blow the motor pretty easily.

-shaeff

yes i have a fuel cut defenser, whe here cal it a "box",i whent to my mecanic yesterday and whe put a fuel presure gauge in the injector line and in aceleracion the pressure drops quit a bit,maiy be thats the problem i already ordered a fuel pump walbro 255lph it maybe solves the problem dont you think??? just to think that i could blown the engine its not good to think about it

fuel pressure drops when you accelerate? that's DEFINATLY a problem. we have risisng rate fuel pressure regulators. when you increase the throttle (throttle plate opens) fuel pressure should rise, not drop.

if you're putting in a walbro fuel pump, you have to bypass or drill out what we commonly refer to as the "J-tube". it's located on the intake side of the motor, and is bolted under the intake manifold. it has the return line for the fuel tank connected to it. you can bypass it with regular autoparts store fuel hose, as it doesn't need to hold pressure.

the problem could be several things-

1) bad fuel pump
2) clogged fuel line(s)
3) clogged fuel filter.

go ahead and replace that fuel pump anyway, it's old, and probably tired out. it's a good idea, and good preventative maintenance.

here's a picture of that "J-tube" i'm talking about:


-shaeff

thanks it was a good help

yes fuel pressure rise but them it drops hover 1 bar...thanks for the help

my car is fine now,after puting the walbro pump the car is much beter and faster,now i ordered a stage 3 clutch because the stock one is not olding so much power lllooolll supra rules ...

good to hear!

-shaeff

shaeff my car still fails ....if i shift to fast it makes a pick of 0.9 bar and it fails,if i take time between shifts it doesnt fail and in the apexi super afc i cant give more fuel% because it fails more...i dont understand in the apexi the fuel % its stock..please help me with this...

i have an auto gauge fuel rich ou lean...and it only lights the green light.... the scale is 2red leds;2 2yellow leds;2 green leds; 2 yellow leds and 2 red leds....it only ligts the 2 green doing 0.7 bar,if i give more boost e must give more fuel and whit the apexi if i give more fuel% than stock it fails...i am afraid the engine is running lean...because on stock pressure lights the 2 yelow leds ore some times 1 yellow above the green leds

eek! you're tuning your car using a lightshow AFR gauge!? that's a really BAD idea! you need to pick up a real wideband o2 sensor to figure out what's going on! (and lower the boost for now!)

-shaeff

thanks shaeff...i am afraid my fuel cut defensor is not doing the job ok...i am going to do what you said

no problem. good luck.

-shaeff

my clutch kit has arrived today

very nice! what brand/ clamping force?

-shaeff

"This Clutch Kit has a STAGE 3 RACING SIX PUCK DUAL SPRINGS SPRUNG DISC DESIGN and will hold stock Horsepower to around 425 Horsepower" it doesn't said clamping force...This listing is for a ProClutch BRAND NEW HIGH PERFORMANCE STAGE 3 RACING CLUTCH KIT JDM. Made in Japan....it only said this in the site

i already put it yesterday ...the pedal its a litle hard but ok...in the bening its a litle dificult stop and go but whit practice its ok

very nice. make sure you break it in properly!

-shaeff

i am going to do a few miles before i puch hard on it