Timing is set @ 6* and she still pings on 91 pretty bad in the upper RPMS. My question is would it be worth the effort to find another memcal (to mess with) and have a custom chip burned to correct the WOT ping? or could I safely set my timing down a little lower? Seems like its at the factory spec setting, I don't want to go too much lower. What have you guys experienced with mostly intake and exhaust mods? Could a lean situation be causing this? Thanks fellas

Will

 

Dropping the timing back a LITTLE is safe, but will decrease your gas mileage. I would attach a fuel press gauge somewhere so it can be seen from drivers seat and check fuel press at WOT.

 

I've had 2 original inmolested ones now and i can say that they both knocked like all heck stock or not :-)

Similiar experience with friends cars as well...... Start tuning your own proms u can be doing it for $200 if u play your cards right

LAter
Jeremy

 

My fuel tank is leaking, might this affect fuel pressure???

Will

 

If the fuel tank isn't damaged and it's just leaking due to a pin hole, I doubt if that would effect fuel press. If it's partially crushed or something that might do it. If the high press fuel line is whats leaking, that could cause low fuel press, but that would be a serious leak.

I would remove the fuel filter and try to blow thru it. It should be VERY easy to blow thru. If thats OK, check fuel press.

I also recommend burning your own eproms. It gives you control of almost everything.

 

check knock senser,and put a sanner on it to see if the ecm is picking up a knock signal from senser

 

I replaced the fuel filter just about 3K miles ago. And this is beyond a pinhole leak, I have had two thirdgens, and I have never experience this. On hard cornering, and a full tank, the fuel spills out the filler door and down the quarter panel. I can wiggle the filler neck with some play, and it has a clicking noise, which leads me to believe that the weld there is somehow damaged. Anyone experience this before??? Is it worth it to get a new gas tank, my mileage has dropped significantly I'm losing so much fuel


Will

 

Iron head L98's seem to be prone to detonation at high RPM. It is mostly because the lobe separation angle of the cam is 117.5 degrees. That causes a buildup of cylinder pressure at high RPM and increased temperature in the combustion chamber. Automatics are also prone to detonation during the 2nd to 3rd upshift because of the instant increased load on the engine. Check to make sure that your fuel mixture is correct. A quick way is to read the O2 sensor with a voltmeter at WOT. It should be about 0.88-0.90volts. It you still have a problem, you could change the spark plugs to one heat range colder. I did that and now it will only ping with old gas, or crappy gas from an unknown source. Stay with 93 octane from Mobil, Exxon, Sunocco, etc. A fuel tank leak shouldn't affect the fuel pressure, but you really should get it fixed.

 

91 is all they offer in Cali. The nearest 100 octane is 50 miles away. And at 3.00 a gallon, I can't afford to throw even a couple gallons in to mix.

Will