SR20DE sluggish acceleration...

[m3nt0r]

Hi there,

My name is Gerhardt and i drive a 1996 Nissan Sabre 200GXi, which i replaced the motor of with a Japanese import SR20DE. when i swopped motors i also swopped the following with my original parts, AAC Valve, TPS Sensor, Distributor, Feul Rail + injectors and flywheel.

Changes made to the motor; 268degree camshafts, VDO 3.8bar in tank petrol pump, feul pressure regulator (which takes te feul pressure up to 5.7bar), lightened flywheel, custom intake pipes, cone filter, branch, F1X Freeflow system and NGK-R spark plugs.

Now my problem is the following, when i accelerate it feels like something is holding by my car, like some kind of restriction, yet after my revs reaches 5500rpm there's a sudden "burst" of acceleration and from there on my car revs like it should as from the start. I've checked my timming and tried anything from 15- to 17degrees, i've adjusted my idle air screw on my aac valve - NO LUCK - i've spoken to a couple of guys and they all say, FEUL PRESSURE, but my feul pressure is 5.7bar and that's MORE than enough!!! i've cleaned my throttle body and airflow meter...NO LUCK STILL!!!!! i've check for leaks on my intake and exhaust manifold, NOTHING!! we had a vacuum gauge on it to see if there is a leak on the valves or something, but the gauge shows absolutely NO PROBLEM!!!???

I'm outta idea's, i dont know anymore, at this point im ready to just get rid of the damn car and get myself something else...but i like this car and cant get myself to sell it.

I REALLY HOPE SOMEONE CAN HELP ME WITH MY PROBLEM!!!! my skype contact is mentor19505 and my google talk is [email protected] that's also my email, if ANYONE can help me, PLEASE!!!!!! i'd appreciate it VERY MUCH.

thanks

[RED_DET]

My question is why are you running so much fuel? This is a NA motor, correct? Regardless, what are you using for engine management since you raised the fuel pressure? You can't expect the stock ECU alone to compensate, it has no clue what is going on.

I say that is exactly what your problem is, get engine management system, S-AFC will work fine. Or return the fuel pressure back to 3 bar.

[m3nt0r]

hey there, thnx for the reply...

ok so fair enough, my feul pressure might be a bit high, yet my friend driving the EXACT same motor as i am, except being STOCK, are also running at boost 5.7bar,yet no prob with he's car... i'm certainly not gonna say that your are wrong about the pressure, yet, if i drop the pressure i dont get the performance i want out of the motor, that is actually a fact and proven so on a dyno running low pessure with the AAC valve restricting the air quite a bit lowers the KW im getting on the flywheel, and also having my pressure so high and the AAC vavle letting through a generous amount of air, does make the car heavier on feul, but my throttle responce is MUCH better...

never the less, i did turn my boost down to 3.0bar like you suggested and tweaked the air a bit...without any luck, still getting the bad acceleration and throttle responce also went down.

after fiddeling around a bit earlier on, i seemed to have MAYBE found the problem, it seems to be a defective AIRFLOW METER... im not sure if that can be the problem but after doing a test, it seems to be right on the dot!

NOW, where the heck will i get an replacement airflow meter? i also read that if you install a management system like the gotech mfi, you can actually REMOVE the airflow meter? is that true? then another thing i see is, it mentions a LAMBDA sensor which my motor does not have, but i also see that you only need one if CLOSED LOOP TUNNING is gonna be used? WHAT THE HECK DOES THAT MEAN???

THNX FOR ALL THE HELP MAN!!!! i REALLY appreciate it!!!

[RED_DET]

ok, you are confusing me. you said you turned the boost down to 3 bar, do you mean fuel pressue? Is this motor NA or boosted? The only reason I would ever see the need to turn the fuel pressure beyond 3 bar would be for high horse power turbo applications or NA applicatons where nitrous was being used. But anything over 4bar fuel pressue is just ridiculous. Injectors are a tricky thing, too much fuel and you can cause them to go static and stay stuck open. I stated you need a engine management system because you are turning up the amount of fuel being supplied to to the injectors. If the ECU doesn't know what the hell is going on, it can't adjust properly. This is where a S AFC can come in handy.

Take for instance on my car, the ECU is programmed for 370cc injectors to run @ 4bar. But I am using 444cc injectors @ 4bar. If I didn't have the S AFC to adjust for all the extra fuel, my car wouldn't run properly.

Now onto the MAF issue. A bad MAF will cause the problems you mentioned. Have you check the maf voltage and re-grounded if necessary? I assume a gotech mfi is similar to E manage here, in which you can run the car without the MAF. It is actually called a "blow throw" design. LAMBDA is actually a wideband sensor. I have a wideband sensor hooked up on my car and it reads Air Fuel Ratio and also LAMBDA.

[m3nt0r]

Sorry for the cunfusion bro, when i said boost, i actually meant feul pressure, its the way we talk down here. anyhow, the gotech mfi is exactly what you said, when you install it you can remove your maf, which is for the best cause mine is just pi$$ing me off!!!! haha

i'm looking for someone to install this management for me now so that i can get back on the streets and have some fun again.

[nnkfws333]

Try disconnecting your TPS and see if it makes a difference. I had a similar problem with my SR20det, disconnected the TPS(which was bad) and was able to drive it until I found a replacement.

AB