Vacuum???

Hi there.
Ive recently got a s13. I was a bit over eger so didnt check it out well enough before buying it. I corrected the cam timing witch was out by a tooth on each wereafter the car went better but still sluggish under 3000rpm. When it started boosting at 3000rpm it felt o k but still didnt pull all the way to redline. Then i did the ignition timing and fitted a boostgauge ,now its fine up to 3000 where it then starts to stutter, backfire and jerk, not so bad in firstgear. If i feed the throttle gradualy it wil revs thru but not as it should. Im not sure about the vacuum layout and think i might have lack of feul. I think theyve worked the turbo aswell cause according to my gauge it boosts 1bar. Any sugestions.

Charlvdw

Sounds like surge.
Could be vacuum leak, check with some of these guys on the forum relating to the fault codes on the ecu as well.

Check your Fuel pump and replace fuel filter (check fuel pressure after the inline fuel filter.

Last thing from me - fuel pressure regulator

That sounds like a fuel problem, when it really needs fuel there is not enough and the car jerks and so forth.

Charlvdw wrote:

If i feed the throttle gradualy it wil revs thru but not as it should.

that makes me think its electrical. sensors like the water temp, AFM, TPS, not working correctly, or not talking to the ECU correctly, would cause this kind of problem.

are you 100% sure that the timing is now right??? you said you changed it, was the car running nicely when you test drove it before you bought it???

also, boost leaks will cause this kind of issue.

and boosting 1 bar on a stock turbo will cause it to fail quite quickly. its not going to last for a year, so fix that too!

Thanks for the replies!
Cam timing i'm 100% sure of the ignition timing i set to 15degrees if the second mark on the crank pulley is the 15 degree mark? The idling did sound better after this ajustment but there is still a miss coming thru from time to time far better than wat it was. You cant ajust the wastegate on the turbo so i supose they've changed somethin inside i would like to bring the boost down. The vacuum pipe on the back of the intake also blows of some times. Doesnt anyone have a vacuum diagram, the ones i've found are all for the jap-spec with that secondary butterflies.
Nice to actually speak to people that is as or even more enthusiastic about this car than me.

The only way for them to up the boost was to ad a T peace between the comressor housing of the turbo and waste gate(actuator) of the turbo to bleed air causing the waste gate not to open enough witch increases boost, somewhere there must be a manual or electronic tap(boost regulator).

Easy way to fix this is to put a 8mm selicone pipe straight from the comressor housing to actuator....if it still boosts that high your actuator might be faulty and not open as far as it should.

hEY DUDE IF YOU IN DURBS CALL ME I CAN HELP , SOUNDS LIKE EXACTLY THE SAME PROBLEM I HAD,, CHECK MY PREVIOUS TOPIC
OVERBOOSTING

Thanx Draco
The comressor housing is connected to actuator, so i gues that the actuator could be stuffed.

RBSX
Sory mate im not in durbs but if read youre previous topic, still i couldn't get the sulotion to youre problem there. What did you find at the end of the day? Tell me the FPR does the feul pressure increase under air pressure(boost) or at atmospheric pressure?

I have seen that the waste gate in the exhaust housing rusted the waste gate and exhaust housing together also sometimes carbon buildup that mix with oilyness that keeps the waste gate from opening....

Your FPR gets the right pressure from your head and from the pressure solonoid valve, as this increases the FP increases...

So am i right to say that to high pressure from the intake manifold would be bad for the feul pressure aswell?

In theory you are right but 1 bar is not enough to sereously increase FP to cause this, if your car is overfueling badly you will see thick black smoke out of the exhaust on aceleration....

Tell me witch vacuum pipe go where on the pressure solonoid valve?

From the air intake black pipe(between the turbo and air filter box)there is a thin black pipe connected from there to the solonoid, from the solonoid it goes via the back of the engine to the FPR, the same pipe is T pieced from the back of the intake manifold to FPR. That is if my memory serves me correctly....

Im still not clear witch pype goes to witch one of the three on the pressure solonoid valve.

I'll have a look and post on monday....

if the second mark on the crank pulley is the 15 degree

Second Mark reading from left to right is TDC when standing in fount of the motor
Second Mark reading form right to left is 15 degrees when standing in fount of the motor

1 bar on the stock turbo is Madness in my eyes; anything over 0.8bar is going to heat soak the IC super quick and be just hot air.
But I’m sure Draco can sort you out in no time.

Also check you AFM maybe give it a good clean and pull some codes on the ECU maybe that can give more information
Possibly check the fuel pressure as well.

phinx beat me to it.

if you're facing the motor and looking at the second mark from the left its 0 degrees broo!!! wont run that well!!!

also, if you have pressure coming out of one of the vacuum pipes while hte engine is running then something is definitely wrong with your piping.

you actually dont really need to use the pressure solenoid. well, there's a whole bunch of stuff that can be removed from the engine, but thats a long story.

no-one has asked yet - is it a stock turbo. the same one from the factory, cos then sort that out first. i get the feeling it isnt stock, and if its bigger, then at 1 bar, there's no way the stock fuel pump and FPR can supply enough fuel for your engine to burn properly.

good luck!

Hi there

Got the timing right thanks for advice on the marks. I also modified the actuator arm and its now ajustable. Everything if smooth at .4bar but then i went and put it up to .8bar again witch is less smooth nicer but allmost drivable. If i want to dyno and so on who would you guys sugest? And whats best as after market pump and fpr and where do i find it:?: