View Full Version : cant lean out

05-10-2004, 03:42 PM
I cant lean my car out past 10.5:1 with out getting knock :mad:

I checked and set my base timing, which was way off... 20 deg advanced :eek:... which was the way I bought the car, and I just never checked it

so now its at 5 deg btdc..... which let me lean it out alot, but not enough. I'm at 0 correction on the afc, but should/need to be -15 or more.

relevant info on setup:
completely hacked maf (so 25% more unmetered air)
680cc injectors (50% more fuel)
front mount intercooler
14b turbo @ 15 psi

I've tried just setting it at -10 across the board, which netted me 11.5:1 and a hole lot of knock.

What else should I check?
plug wires are only 4 months old, no sign of a miss
no major boost leaks, i think 1 pin hole leak


05-10-2004, 04:34 PM
reduce the BTDC to 0 or 3 degrees and give it a try. Make sure you are using quality pump gas. If you have -10 across the board that means you are lying 10% less air comming into the engine, so the ECU would place you at a higher timming table and cause knock.

05-10-2004, 07:56 PM
Base timing should be between 5-7 degrees.

What fuel were you running and where did you get it?


05-10-2004, 10:30 PM
91 octane from a Shell station I always go to.....

I might have to get some 100 octane and see if that will let me lean it out.

I dont know, its real wierd. I mean my timing is where it should be, and I've checked and replaced the obvious stuff for the most part.

One thing I did notice in the past 2 days is that one of my injectors might be bad. Twice now the car has all of a sudden started running on three cylinders. I've checked all the connectors when it happens and there was no change. I also unplugged the #1 injector while it was happening and the idle didnt change. There was no CE light or codes when it does it.

So I'm probably gonna stick the 450's back in, and see if I can get those to lean out and run right.

05-11-2004, 07:15 AM
Sounds like the wires for the injectors are starting to crack. You may have to re-do that wiring.