The engine ran extra smooth after I installed it with no codes,car idles smooth.The problem is when I checked the timing its at zero(brown wire off)When I put it to 4 degrees it pings on load.Fuel pressure is at 47 psi.Im going to put 94 octane on it(92 now) then bump the fuel pressure.I resetted the TPS and IAC and noticed that my idle screw is way in so I backed it out(my friend adjusted it without me knowing)Now the car wouldnt start unless I step on the gas and theres pinging at load.I also have the custom MRP chip(PR chip)thats for a stock 350 with a 160 degree stat,2 degrees advance,raised fuel pressure and stock cam.I will put in the stock chip if the better gas and pressure doesnt help.I also noticed that its getting its total advance way early(less than 3K RPM).Am I missing anything?I just think that Im not geting its full potential at zero degrees not to mention the bad idle after doing the TPS.What is the best way to find out the cause.Mods/combo below

87 IROC
383 10.4:1,TFS G1 heads(fully ported),
220/230 duration,.510 lift 114 LS installed with no advance.
Stock 22lb injectors at 47 psi
Accell supercoil (remote),new wires and plugs


[This message has been edited by Daz (edited September 25, 2000).]

 

anyone??

Daz

 

Daz,

A lot of conditions cause pre-ignition:
advanced timing, carbon build-up, static/dynamic compression too high for the fuel, high combustion temperatures, lean fuel mixture.
I assume this is a TPI engine (47PSI). What mods?
Did you say that you just installed it?
What is the make-up of the engine, heads, cam, etc.?
How many miles on it?
Ping on load only? At any special RPM (top-end, lugging)?

 

Mods are above plus a Superram,headers,no cat
As fo mileage its a newly built engine by a race shop.Ping is on load only,it starts right before 3K.Sometimes it would stall when put into drive from park.

Daz

 

Sorry about that. I missed your sig.
I realize a 383 can take more compression than a 350, but even with aluminum heads you must be on the ragged edge.
I would think you need to have your advance curve very specifically and very finitely tailored to your fuel curve to avoid detonation.
An "off the shelf" performance chip is set up to add some performance to an otherwise stock, 225-250 hp engine.
With the mods and displacement you show, yours should be in the 375-400 hp range.
Contact Howell Engineering or one of the other custom chip burners that others here have used.

 

AZDAVE,
So you think even if I fix the pressure/gas problem that I should still get a custom chip??

Daz

 

Your initial advance is not nearly as important as your total advance.
If you want all the performance this combo can produce - get a custom chip.
Talk to the programmer directly.
Be patient, it may take 3 or 4 tries to get it right.
You can help out by taking some vacuum readings under different conditions of load, RPM and throttle opening. Readouts from a scanner - O2, block learn, integrator - would be even better.
Hate to see you you melt down that sweet, expensive motor.
Think of the chip as a combination performance mod and insurance policy.
It will be well worth the price.