Dave Creaser

So the previous owner had my 98 trans am ws6 tuned on Speed Density, and my car has started running very rich and bogs down in low RPM's and is throwing code PO103, I didnt think I could get a MAF code in speed density?? not sure what is going on, is it the tune going bad or do I need to replace the sensor on the maf even though I am running Speed Density? confused...

ICRAZY6

iTrader: (68)

If your running speed density and it was tuned as such you wouldn't get a MAF code at all. The MAF would have likely been removed as well and just a piece of pipe or coupler would be in it's place. Now if the previous owner unhooked the MAF to "fix" another issue and it didn't throw a code for a while, I could see that. You could always plug the MAF back in and see how it runs.

What work is done to your car? The reason most tune for speed density is because the MAF won't read correctly for boosted applications and a few extreme NA combos.

Something is fishy here.

Dave Creaser

engine mods are:

-LS6 Longblock
-Brian Tooley Racing Stage 4 Cam
-Advanced induction 226cc 243 heads
-LS2 Lifter Trays
-LS7 Lifters
-TSP Hardened 7.400 pushrods
-Brian Tooley Racing Trunion Upgraded Rockers
-Brian Tooley Racing valve springs
-ARP Head Bolts
-LS2 Timing Chain
-Fast 92mm intake manifold
-Nick Williams throttle body
-Greentop 42lb Injectors
-TSP 100mm MAF
-Fast toys 104mm lid
-Fast Toys Ram Air Mod
-SLP UD Pulley
-Aeromotive 340LPH Fuel Pump
-Ractronix Hotwire Kit
-Kooks Long Tube Headers
-Kooks Catted Y-Pipe
-Borla Cat-Back Exhaust


the MAF is plugged in right now and was when i got it, but previous owner said its in SD tune and the computer isnt looking at that or the rear 02's

does it need a new tune? or is some sensor in need of replacement? like I said it seems to be running rich and bogging in low RPM's...

Dave Creaser

could it just be a failing 02 sensor? no code for them but ive been told that it wont throw a code until it is completely shot

fst100

iTrader: (5)

with long tubes, I would imagine the tuner would of turned the rear O2s to not register at all. don't know much about SD tunes but do users generally turn off anything regarding the MAF including P0103?

Dave Creaser

Rear 02's arent being looked at but the fronts are he said

2xLS1

iTrader: (25)

You have to fail the MAF and set P0103 in order for it to run in SD. You can set up the tune for it not to turn on the SES light but the code has to set.

joecar

+1 the presence of a MAF DTC makes the PCM run SD

( the DTC can be present even if the SES/MIL lamp is not enabled for it )


The tune does not go bad.

If the problem has started happening, then something has "broken" and needs to be diagnosed... if it started running rich, then you have to look at the possible causes of this (e.g. leaky injectors, failed FPR, ...).