3rd Gear Knock

[letemlaf]

i recently had a pfc installed and tuned by hyperdrive on a 33 gtst.

All seems to be well but i have noticed that occasionally the knock seems to jump to excessivley high readings. It would generally jump to a maximum of about 70 and my mechanic told me it is probably because i need to install an aftermarket fuel pump.

The issue im still concerned about is that the other night i gave it a bit of full throttle action in 3rd gear on the freeway and had a knock of 122 (running 13psi)

the values are as fallows:

speed: 107

ign: 43 (maximum value on pfc so i dont know if its the value at time of knock)

airflow: 4690

rpm: 4844

inj: 68.7%

knock: 122

temp: 81

From using the search button ive found it could either be a faulty knock sensor or poor tuning, or is this still in relation to needing to upgrade the fuel pump, even though the inj duty is 68.7%?

any help is appreciated coz i like my engine in one piece!

[wilch]

Hmm, If I were you I'd go to a dyno and get some A/F readings.

Could be running lean, which isn't good. Now that might be because of a dud fuel pump, or the tuning (seeing as the inj duty is only at 68.7%).

Can't tell really unless you get some A/F readings, and even then it could be the tune, or not enough fuel pressure.

[R31Nismoid]

Take it back.

Have the cell thats got the incorrect timing value altered.

If you provide RPM/Throttle position/speed/gear then it should be a 5 min job.

[paulr33]

if you wanna try and fix it yourself you can give it a shot, its fairly easy, the powerfc faq in my signature tells you how to do this.

also you should have a GTR pump ideally around 180rwkw ish in an r33.

also 13psi is pointless and just adding extra heat, drop it to near 12

[In Tune Performance]

Hey there mate my name is Aaron and i am in the process of opening the doors of my new business In Tune Performance and Engineering which will be located in Oconnor Western Australia and will be opening on approximately the 17th of this month. From my experience a fuel pressure and fuel flow test needs to be carried out and probably a replacement fuel pump upgrade will need to be carried out. I don't believe that there would be a tuning issue such as has been noted. Hyperdrive would not have let the vehicle leave with a knock reading of 122. Something else has happened since the vehicle was tuned there. If the vehicle needs a new fuel pump i would recommend an adjustable fuel pressure regulator be fitted at the same time (not a Malpassi) as the vehicle will need to be re-tuned once these mods have been done. I also agree with one of the other posts recommending that the boost be dropped to approximately 12 psi if you are still using the std intercooler otherwise 13 psi will be ok if you are running an aftermarket front mount. My business will be providing a full dyno tuning service and i specialise in Motec, Haltech, Microtech, Autronics, Power FC, and Xede as well as most other systems on the market. Feel free to call anytime for advice or service on 0414874824.

Good luck with your project.

[R31Nismoid]

Fuel reg is not required.

And its highly possible for a car for have 122 knock.

Dyno tuning sometimes does not cover ALL conditions that the car/tune will be subject too.

[R31 POWER]

I better take mine back to then.

[Cubes]

I find I always have to slightly tweak my tune after its been tuned on the dyno.

As stated above, its impossible to cover all conditions.

[letemlaf]

thanks for all your suggestions i will look into them

if you wanna try and fix it yourself you can give it a shot, its fairly easy, the powerfc faq in my signature tells you how to do this.

also you should have a GTR pump ideally around 180rwkw ish in an r33.

also 13psi is pointless and just adding extra heat, drop it to near 12

I will have a look over the next few days at trying to fix the problem myself.

I am a little worried that a knock at that level might kill my engine if i get it wrong so ill read through and take it easy

Im also looking at buying a bosch 044 pump, would it be worth installing the pump before i go ahead and try to fix any problems?

[R31Nismoid]

I dont believe it is a fuel pump issue