Zmego1985

iTrader: (1)

Ok i upgraded my heads on my Z by porting and polishing the heads having bigger springs put in, 1mm larger valves radius cut in, titanium retianers, and different locks put into my heads with my JWT cams. The problem being more engine noise from the upgraded head components has occured. Now the knock sensor is detecting these noises, and retarding my timing, because its thinking the engine is pinging or having other problems. The timing gets pulled back the most at high rpms, because this is the point of the most engine noise. So to fix the problem i can take the knock sensor out, and put nylon washers under it so it can't detect the new noises or vibrations. If this does not work is it extremely unsafe to have the knock sensor taken out? Can i please have some more info on what can happen if i need to disconnect it.

Also i found this out after dynoing, and having horrible dyno numbers and loss of timing on my ecu at high rpm's. So I sent it back to Technosqaure to have it looked at, and i was told this was happening from the program read out they had.

Just wanted to let everyone know whats happening to me so this does not happen to you.

Thanks Glen

Zmego1985

iTrader: (1)

Ok i finally got the time to put the washers under the knock sensor, and put the ecu back in after technosqaure fixed it. I dont feel as if the washers have worked to dampen the sound from the new valves. I will dyno the car again monday to see if i have more power, and keep you all updated. If the ecu keeps pulling timing, because of the knock sensor im going to have technosqaure remove it from the program. I will keep you all updated.

Has anyone else used the ferrea valve kit besides me and has had this problem?

Thanks Glen

phunk

iTrader: (21)

im not sure you should really be getting that much noise from your new setup. but i havent played with our knock sensor yet so i am not sure... my car currently doesnt not even pay attention to it. my ECU ignores it at the moment... im gonna use it later tho.

i would be concerned if your head work is done correctly.

you didnt mention anywhere about replacing lifters... after all this work to your head, surely you would need to replace the lifters to get your valve clearance back in spec. was this done? its a process of swapping around and replacing lifters until you have a combo that puts all valves at proper lash.

Z1 Performance

iTrader: (564)

washers wont work...you need something to dampen the sound. A metal washer simply transmits it.

I agree with phunk as to the clearances etc. Plenty of guys have cams and springs and have not reported any issues

Zmego1985

iTrader: (1)

Im not sure i thought our cars didnt have lifters. I was told the cam rides right on top of the valves. I also looked up ferrea valves on other cars like the 300zx and supras, and they cause a great deal of louder noise, because of the new components and dual coil springs. I just have to have the knock sensor taken out of my program. The only way i knew the knock sensor was retarding my timing was from technosqaure reading it from the program. I had no check engine light either. Im gonna bring it to the dyno monday to see if the nylon washers helped at all, and if it didnt i will have the knock sensor deleted from my ecu. My timing was all the way down to 12 degrees at wide open throttle. I had better timing at partial throttle. I will try to figure this ordeal out soon, because I want to help everyone out, and get my Z fixed before winter.

Thanks again for all your help

Z1 Performance

iTrader: (564)

no knock sensor on a car that you drive on the street and have no control over the program = bad idea

Zmego1985

iTrader: (1)

Can you think of any other options to fix the problem?

Thanks Glen

John at J&S

Electronically desensitize the knock sensor, using a voltage divider made up of two resistors.

At the ECU, cut the knock sensor wire and install a series resistor. Install a second resistor between ground and the knock sensor input at the ECU.

With equal value resistors, the signal is cut in half.

The Nissan knock sensor has a high impedence output, so the resistor to ground should not be less than about 500k ohms.

I recently saw an add for a $30 Greddy box that lets you tweak the knock sensor signal.

phunk

iTrader: (21)

I find out about your heads first. this head definatly DOES have a lifter and unlike a VG30 motor it is NOT hydraulic... it is a solid lifter and the only way to adjust valve lash is to replace the lifter with a different thickness one. If this was not done, your very likely to have some serious problems soon. replacing valves and/or doing a valve job REQUIRES valve lash adjustment is it moves your installed height.

Find out this first. This is very important. if you have to take you car to Nissan for valve lash adjustment, do it... because if your lash is too tight or way too loose then you are gonna have some serious problems.

Zmego1985

iTrader: (1)

Thank you so much for the info.

Zmego1985

iTrader: (1)

Im having the knock sensor taken out this problem is driving me crazyyyyyyyyyyyy!!!!!!!!!!!

Thanks Glen

I have also been reading through the boards that the underdrive pulley can set off the knock sensor to retard timing. Is this statement true?

John at J&S

google Greddy+15900903.

They call it a knock sensor adapter, to prevent unwanted retard from a knock sensor.

spazpilot

iTrader: (2)

I would really look at the head work and no the UR pullies on this car do not set off the knock sensor. I have them on my car.

ktown z

iTrader: (8)

Sorry to be off topic, but what kind of head work is required to use the 1mm oversized valves. Can they be used to a stock head?

Z1 Performance

iTrader: (564)

I have a question - with ALL that head work and cams, and hecne the extra flow, what did you do in terms of fuel and ecu? I see you have a reflash, but it is certainly possible the knock sensor IS seeing detonation

Zmego1985

iTrader: (1)

Technosqaure said they looked at it and it looked fine. I was running richer at higher rpms a 12.8 Can this be the problem. They also said the knock sensor is going off and thats why the timing is so low at high rpms, and thats why I dont have the power.

Thanks Glen

Zmego1985

iTrader: (1)

Do you think they gave the ecu to much timing causing detenation?

Thanks Glen

mprowe350

TS uses this excuse too much. Check your heads or fuel system there's something wrong. How is TS reading the info you talk about. The ecu doesn't even store how rich or lean the tune is. In fact at wide open throttle, when you say the problems occur, the o2 sensors aren't even read the ecu follows predetermined specs set forth by TS? However these predetermined specs result in different A/F ratios in each different car. I wouldn't trust TS, they really have no way of telling unless the car is in house.

Zmego1985

iTrader: (1)

Sorry what i ment to say was the dyno run showed i was running richer a 12.8, and technosqaure could tell the knock sensor was pulling timing for some reason.

Thanks Glen

mprowe350

OK that explains it better. TS told me the samething one time when I had some concerns, turned out to be heatsoak. Good luck getting things fixed.