I was looking over some scans I grabbed earlier this year and was trying to figure a SR problem. It seems that when I'm at WOT and in 3rd gear I get a lot of SR. Funny thing is this doesnt happen in any other gear (1st and 2nd). I was curious as to why it would happen in 3rd as opposed to the other gears, seeing that I hit the same RPM in all gears!?

Suggestions, comments?

Mods to L98 91 GTA:
24#inj.
MSD6a
HSR
LT1 cam
KN
Catbak
!EGR
!AC
!Smog

Here is a csv file of one of the runs.
http://www.mafba.org/images/jtw/Indy...e_09252003.csv

 

More load on the engine most likely.
Less gear multiplcation.
A little less SA might cure it. Obviously..
I don't know if this translates to an EFI car, but a carbed car can run out of fuel about the time you get to 3rd. Takes that long for the level in the bowls to drop enough to affect the AFR.

 

Are you sure it's not an engine noise or rattle of some sort?.
Odd to get that much SR just in third.

Fuel pump and filter OK?.

 

If I pull any more SA out of it I wont have any up-top

 

I dont believe that its an engine noise causing it because I would imagine that it would have the same effect through all gears and rpm ranges! Not only that but she feels and sounds very smooth throughout the trip down the 1/4mile.

I do have a new fuel filter to put on, and I think my fuel pump is ok. Maybe I should consider getting one of them fancy electronic fuel pressure gauges so I know what kinda pressure I'm running up top. Since I have put the HSR on, I havent really done much checking on that!

 

You knock sensor could be in too tight, or you might need a touch more fuel up there, or you have too much spark. Try some higher octane gas?

 

The knock sensor has never been touched and I run 93 in it all the time. I'm going to put in a new O2 and make a few runs and see what happens....then I'll add some fuel up top and see if it clears it up!

Thanks for all the advice!

When I get it figure out I will let ya'll know what the fix was!

 

Wow, it really starts to pull some timing doesn't it? Looking at the data log that area (MPH) is right around where the TCC is forced to lock. May want to lok at that and maybe set it higher and retest.

RBob.

 

Good call rbob, I was kinda thinking that maybe it was the load on the engine that was causing it. I will definately give that a try as well!

Another thing I just remembered was that I have an old stock coil. When I put my HSR on, I accidently plugged the wrong stuff back into the MSD coil and blew it up. Maybe I should think about upgrading my coil along with my O2 and see if that takes care of things!