Loss Of Power After Service

[PhilGTR]

i am using 5w-50 oil, i think he said motul.

my mechanic plugged a little computer into my car near the steering wheel to check everything like afm voltages, coils etc and reckons all is ok!

Its intermittent, sometimes it lacks a bit of response, kinda like something is holding it back but other times it drives beautifully, good response, pulls harder too. At first i thought it was in my mind but i dont think so anymore! Strange thing is i never noticed this until right after i got my car serviced. Im confused :| According to my mechanic my car is perfect drives very nicely.

It usually happens after i have driven for a while and everything has warmed up. But then sometimes when i turn it off for a while and start it again when things r still warm, its ok again!

[Green_s13]

does the car feel good when say on the freeway when moving, but then bad when sitting at lights and slow speeds?

also i would check to make sure you ignitor earth is nice and tight.

[PhilGTR]

does the car feel good when say on the freeway when moving, but then bad when sitting at lights and slow speeds?

also i would check to make sure you ignitor earth is nice and tight.

Hmm it seems to happen after a bit of traffic. but once it feels sluggish, it stays sluggish until either it cools off, or sometimes when i start the car again. But everytime when the car is cool it runs well.

Will check the ignitor later

[PhilGTR]

Hey fellas!

I finally figured out what the hell was wrong with my car, or should i say nothing was actually wrong!

I discovered today that my boost restrictor has been removed. And on the stock guage it hits +7 which is almost 14psi ay like 3krpm ish

Before the service it musta had old plugs, air filter was dirty, old oils etc etc and after the major service everything has been changed and the car went really hard. Which made me wonder how a stock standard GTR could pull like this. This was when my ECU decided its too much boost and must detect knocking so it limits the boost to 7psi and retards my timing so it runs really slow!

If i drive it and not take it above 10psi or 11psi, the car is fine, no retarding no boost limiting, feels good. But when i hit like 14psi, the car is slow. When i retsart the car again, its back to normal!

Is it possible to fit a boost restrictor back in?? Or should i go with a EBC instead? I dont really want to run without a boost restrictor especially when i got an exhaust coming, might keep knocking. Can someone tell me where i can get a restrictor??

[Cubes]

If it is pinging due to the increased boost it 'should' clear up after 4500-5000rpm and rev nicely to peak power.

Last service... Did you have it on the dyno for a power run/check up? It may be the std fuel pump is getting a little tired and as a result its leaning out giving that lethargic feeling.

[PhilGTR]

If it is pinging due to the increased boost it 'should' clear up after 4500-5000rpm and rev nicely to peak power.

Last service... Did you have it on the dyno for a power run/check up? It may be the std fuel pump is getting a little tired and as a result its leaning out giving that lethargic feeling.

Well after the ecu limits it to 7psi, it doesnt pull hard at all, right through the rev range.

Hasnt been on the dyno, but it feels good before the ecu stops it. But it could be a tired fuel pump? Not sure! Because before the service, i never had this rich and retard thing going on. Until right after i got it serviced with new plugs etc etc. But either way im looking to put the boost back to standard anyway, wasnt planning on modifying it much, just an exhaust.

Any one have a boost restrictor they dont want?

Edited May 26, 2007 by PhilGTR

[Cubes]

The boost levels you are talking about >7psi indicates there's a problem elsewhere. Not the ecu limiting what ever. Even if the ecu were to do its R&R or picking up detonation power would pick up after 4500-5000rpm or so.

You need to think is saving $50 for a power run worth the cost for possibly a new motor?

So..... Get it on the dyno for a quick power run.

Simple.

[PhilGTR]

The boost levels you are talking about >7psi indicates there's a problem elsewhere. Not the ecu limiting what ever. Even if the ecu were to do its R&R or picking up detonation power would pick up after 4500-5000rpm or so.

You need to think is saving $50 for a power run worth the cost for possibly a new motor?

So..... Get it on the dyno for a quick power run.

Simple.

Why is there a problem else where? without the restrictor it hits the +7 mark on my gauge. Im pretty sure the ECU cuts boost down that and retards my timing. But why would it pick back up again after 4k rpm? Is the ECU supposed to go back to normal or something?

I wouldnt mind going a dyno run, but i have to get all the way to syd, but maybe worth it like u said. Thanks for your help guys.

[Cubes]

The problem is else where because the stock ecu is fine for running more than std boost.

Knock Detection... The ecu retards timing up until 4500rpmish. Over that it ignores the knock sensors.

R&R... Protects the motor through the critical peak torque rpm. Not high rpm.

Then there's a complete fuel cut...

[PhilGTR]

The problem is else where because the stock ecu is fine for running more than std boost.

Knock Detection... The ecu retards timing up until 4500rpmish. Over that it ignores the knock sensors.

R&R... Protects the motor through the critical peak torque rpm. Not high rpm.

Then there's a complete fuel cut...

Fair enough, so possible fuel delivery problem leaning out? Also the 7 degree temps also doesnt help