Last night a friend and I swapped in a set of JDM spec ITR cams into my otherwise stock 98 GSR. The thing is, it seems like the car is pinging under load at low RPMs. Is this possible? When I say load, I don't mean high load, I mean just load. At idle, I can rev with no problems... and past about 4000 RPMs everything is fine.

Any thoughts?

thanks,
-S

 

Hmm....that's weird. Cams shouldn't really do that.

Maybe your timing is off? Was the timing belt put on correctly? Maybe it's a tooth or more off.

Are any codes popping up such as Cylinder misfire?

 

weird. maybe the different cam lobes needs different fuel setting or air/fuel ratio. i was thinking of getting some type-r cams too.

 

It's recommended that you have the vehicle tuned after any change such as cams. I've never heard of stock R cams causing detonation though. Make sure your ignition timing is correct and your timing belt isn't off.

 

Timing belt shouldn't be off... checked and rechecked... car drives fine, no codes. The only thing I can think of is tha the timing might be off... but then I only losen one bolt on the dizzy(top bolt) to take off the cams....

 

make sure you have redone the valve lash.... might be mistaking noisy valvetrain for pinging?

 

I'll check that out...
Would valvetrain noise be louder underload?

thanks.

 

Yes valve train noise will be louder under load. It will increase in noise and pace as the rpm's climb also.

I dont see anyway cams can cause detonation without maybe some fuel mods.

 

So my check engine light came on over the weekend. 0172 - running too rich. But that's very odd... can running too rich cause detonation? Base on my understanding, running too rich shouldn't cause any detonation.

At any rate, I cheched the timing and noticed that it was set fairly aggressively. Not sure why it would be other than someone made a mistake before I owned the car. The car was second hand, previous owner was a lady who was a professor.

Anyways, I backed the timing off to about 16* and most of the detonation is gone, but under some conditions it is still there.

I'm lost...

 

you do know that when you make a swap like that..you do require a valve adjustment ($80 or so)...as for timing...you should leave it at stock until you get that done...unless that is stock...

 

sounds like a valve adjustment is in order

 

change your plugs and check the gap?

Premium gas? Did you accidntly fill 87 octane?

thats all I can think of now

 

For future references:

I started getting check engine light with a code of 0172 - running too rich. One of the causes the manual said was valves too tight. So I adjusted the vavles and the code seems to have gone away.

I've aslo adjusted the timing and things sound better.

The only issue is I am getting poor gas mileage now. Where as I used to get about 30 mpg in mixed driving, I am getting 25mpg now. I have not changed my style of driving or route to work.

Plugs, wires, dizzy cap and rotor is next on the list.

 

adjust your valves, problem solved.

 

If you havent already, you might want to reset your ecu. It might need to "re-learn" since you adjusted valves and help with the gas mileage. just disconnect the neg on the battery.

 

after a weekend of driving, things seem a little better. I've had some 3 tanks of gas and finally we are within normal range...

thanks.