Loss of Power

[chrisgero]

Could some one help?

I was driving in Sydney in my Skyline R33 when I was at the lights with a WRX. We both gave it until my Skyline R33 pushing 9lb just over 5000rpm started to get a jerking feeling as the harder I accelerated it didn’t want to go any further. It felt as if I was loosing power after 5000rpm.

Has anyone had this problem, my vehicle is standard just a boost controller set at 9lb.

thanks

Chris

SYDNEY

[BenA31]

fuel pump, boost leak........

[Craved]

have you got a boost guage in the car? how bad is the jerking?

[Tommyk]

Yeh i had a similar problem just before i sold my 33

Its the distributor/coils

[ALL GTR]

I had the same problem with my R32 GTR it was the cooler piping had came off. When I went down to ask them what it was they said one of 2 things.

Either Spark Plugs or the Pipes leaking.

[Blade]

I had a similar problem

wat does ur boost gauge read?

if its spiking

Check that your hoses arent bent...could be as simple as that...bent hose can make ur boost spike bad...and after 5000rpm like in my car...it jerks and i had bad loss of power.

[Bass Junky]

The gods of responsible Skyline driving realised you were being bad and decided to punish you and restrict your power until you get onto a racetrack

[chrisgero]

have you got a boost guage in the car? how bad is the jerking?

The boost guage is in the engine bay, as I was pulling away from the WRX and the Skyline hit 5000rpm that when I got power loss, like it wanted to back fire as i was accelerating.

[chrisgero]

I had a similar problem

wat does ur boost gauge read?  

if its spiking

Check that your hoses arent bent...could be as simple as that...bent hose can make ur boost spike bad...and after 5000rpm like in my car...it jerks and i had bad loss of power.

My boost gauge reads 9lb, i dont get no spikes. I recently had Turbomaster it was bad, spiked a lot now I bought GF fast bits, no spikes. I will have a look to see if the hoses are bent. During the week the car sits in the driveway as i am a shift worker. I had the car since January and only done 4000klm. Im only running standard intercooler, if i get a large front mount intercooler will i notice a difference when racing WRX's. Also my plugs haven't been altered for the 9lb. Could this be the problem.

chris

[sewid]

Stock ECU? Then its probably the boost cut.

[Lozza150]

Either that and or check these things.....

1. AFM might need a clean due to oily filters or excessivly dirty filters.... do a search on AFM cleaning.

2. New Spark plugs Gapped to .8mm either platnium, Iridium or check out "Champion" for a cheaper alternative

3.Reset ECU. Disconnect battery and touch break pedel

4. Check all vacuum hoses

5. Check o2 sensor (over fuelling or exxessive fuel use is a sign of failure)

6. EBC if you are using bleed valve

if all above fails, dig deep and see a mechanic, and let them know of your progress thus far...

Cheers

Lawrence

[CAMLZ]

Hey mate i'm currently having the same problem with my 33. it could be one of three things that i have worked out.

your computer is only registering stock boost and pushing enough fuel through the turbo and the car to register 7 pound when ur actually running 9

the fuel cut defender

or your air fuel ratio sensor. I've posted the following so if you want keep an eye on my posts and see what poeple say and the advice we receive..

Adam

(my previous post)

Hey all,

I own a R33 and have recently fitted my front mount, now whenever i boost the car up past 10 pound and i get the revs up to around 4500 i get a series of backfires comming from the muffler, it feels like i'm hitting rev limmiter and i loose power. I have kind of narrowed it down to these following things.

1 my computer. I'm not sure if it is only registering 7 pound when i am running 10 and only putting enough fuel thru the car the accomodate this.

2 My air fuel sensor might be stuffed up. If it is i have no idea how to get it fixed or what i should be doing with it.

If anybody has had the same problem with their car cause i have heard this is kinda common can u please let me know what you did to fix it and how much it costs.

I will be getting the car dyno tuned soon so hopefully that might also be able to work out the problem.

Thanks

Adam

[chrisgero]

Thanks for your detailed reply,

I took the non original boost controller off and placed the original boost controller back on which pushes 7lb and the problem is gone. However, on the weekend i will check the hoses on the fast bits boost controller and try to shorten them so i dont get bends or i can turn down the boost to 8Lb instead of 9lb.

I will also look at the other things that you explained.

Thanks

Chris G

[chrisgero]

Stock ECU? Then its probably the boost cut.

Is their a way of getting another chip to boost power or do i need to buy a system like Wolf 3D to increase power. When i used to drive V8 Commodores i had the thing chipped to push 200kw (lump of S#$t) could i do it with the Skyline or do i go and buy intercoolers etc.

thanks

Chris G

[BOOST ON]

interesting.. i run 11psi in mine.. its standard to with only a cat back exhaust i have never had an encouter like that.. let us all know what you come up with

[Lozza150]

Check BOV too, sometimes the stock one might do some odd things......

A mate couldn't run more than 8 psi, changed the bov to aftermarket-no prob's....

So another thing to look at....

[sewid]

your computer is only registering stock boost and pushing enough fuel through the turbo and the car to register 7 pound when ur actually running 9

the fuel cut defender  

or your air fuel ratio sensor. I've posted the following so if you want keep an eye on my posts and see what poeple say and the advice we receive..  

The stock ECU connects to a pressure sensor which sends it the current boost pressure. Unless you have somehow removed this sensor - which is unlikely - then the computer will know how much boost you are running.

If this sensor is removed completely i believe it would run in limp home mode or at least run very poorly. The sensor is a small black box with an air hose connected to it from the rear of the plenum.

The problem probably is the stock ECU seeing too much boost (around 10 or so psi) so it retards timing and runs rich to protect the engine.

There are probably piggyback systems like the SAFC that can fix and get around this but I have never used them. When i found I was having this problem after an intercooler upgrade - i went straight to the PowerFC.

[croat]

CHRISGERO do a search for "missfire" and a heap of stuff will come up. It is most likely to be the computer dumping to much fuel or plugs or boost cut. It usually happens on a cold night. you should innvest in a power fc.

[b2barker]

The stock ECU connects to a pressure sensor which sends it the current boost pressure. ...

No, in a R33 there is no boost pressure sensor that connects to the ECU. There is one that connects directly to the boost gauge. The R33 works off air flow.

Too much air flow for a given RPM, throttle pos = Over Boost Protection

I have the same issue in my R33. Consult logging has shown the AFM is maxing out which it should not be doing with only filter/exhaust mods and stockish boost.

[SLIM V 2.1.0]

No, in a R33 there is no boost pressure sensor that connects to the ECU. There is one that connects directly to the boost gauge. The R33 works off air flow.  

Too much air flow for a given RPM, throttle pos = Over Boost Protection

I have the same issue in my R33. Consult logging has shown the AFM is maxing out which it should not be doing with only filter/exhaust mods and stockish boost.

:bananaman:bananaman:bananaman