12 Sec GTA

Ok, here we go...



My setup:

1987 GTA
350 TPI
Superram lower manifold, fully ported upper.
52mm TB
LT4 hotcam
Ported Vette heads, 3 angle valve job, etc
1.6 rockers
24# injectors
Granatelli 255 intank
Vortech T-Rex 255 inline
AFPR set @ 47 idle, 55-56 WOT
1.75" shorties, 3" y pipe -> 3" intermediate to single dynomax race bullet.


I've been battling this code 33 for about 2 months now..

My air intake setup is the HomeDepot Racing version.. 45* elbow, to 6" long PVC to MAF to element (not cone, cylindrical, doesn't taper to a cone at the tip)

I've checked for vaccuum leaks, air leaks.
Replaced relays, replaced MAF.
Played with the TPS and idle settings.

Here's what I've found:

If I *dont* let my car warm up before I leave in the morning, it will throw a 33. Which I assume is caused since the last chip I've burned I set the MAF gm/sec to 48 IIRC..

when setting idle speed, if I set it higher than 850 in park, it will throw a 33 due also to the airflow at idle being > 48gm/sec.

My question is, aside from burning a chip (pocket programmer is now defunct, new one won't be here for a month ) Is there a way to beat this code 33..

If it throws the code, I shut the car off for 5 minutes, it will go away and not come back...

I know I could set the idle down some, but then my car doesn't like stop lights because of my cam..

Also, it may just be coincedental, but my car has been harder to start lately-- almost like I have a bad FP relay, but it's brand new, along with the entire rest of the system. (FP is also fine-- it primes it to about 61 PSI prestart.)


Any ideas

88TPI406GTA

No...there is nothing to state that you can't raise the gm/sec limit for the code error to 65 gm/sec. It is only a warning and if you are exceeding it with a cold startup, then change it when you can.

The stock 45 gm/sec (or 40, can't remember exactly) is for a bone stock car. If a 406 would have come stock in the car with aluminum heads and a good cam, etc., then GM would have raised the threshold to NOT set the error.

Just raise the limit enough to compensate for your current setup.

Good luck,

12 Sec GTA

I think you misunderstood me....

I am fully aware I can reburn a chip with a higher flow rating for idle, but I can't at the moment because my programmer was broken, and I'm awaiting a new unit.

So i'm stuck with the current PROM until then. I was looking for any ideas to work around this for the time being

Guest

You'll need to mess with the throttle plate angle and TPS setting. Open up the plates a little more, lower the TPS setting to around .3-.35v. Not the best workaround, but it'll do what you need it to.

88TPI406GTA

Actually, I did understand you...but that was kind of my answer, wait until you can burn the chip again...

I also answered the limit question. My bad, thought that was part of it too.

Uhhh, how about try Madmax's suggestions? Good luck and let me know what fixes it temporarily.

12 Sec GTA

Did some experimenting:


If I pause for about 10-15 seconds after turning the ignition to the on position, and then turn it to start, it will not throw a code 33 off the bat.. I then have to wait for the car to warm up, and drop to about 800 rpms before I drive.. otherwise it will throw a 33 when I start cruising at a consistent speed under 2200 RPMs....



odd..



I'm still eying my igntion module.. wouldn't be the first time a code is thrown for the MAF and it ends up being a COMPLETELY different problem...

12 Sec GTA

Digging up this old topic.

The car was down for some time for the summer..Lack of motivation to put in the new torque converter and some other goodies...


But, I solved the code 33 issue today...

After swapping MAFs, new relays, new everything.. I decided to check out the wiring.

I started off pulling back the convulated tubing that covers the harness wires.. Low and behold, two wires were cut/melted.

I got a schematic and recrimped a new connector on.. Boom. Wonderful.


Now.. to figure out why I'm only getting 3.3V @ WOT on the TPS (set at .54 idle) Brand new TPS..

mrr23

are you sure the TB is opening all the way up. mine wasn't i was getting 3.8volts. then i bent the stop tab until i got the reading to 4.5.

12 Sec GTA

Holy hell... Never thought about that..

I'd put $20 on you being right on that..


Thanks..

mrr23

here's another thing to check. mine was also hitting the worm gear on the clamp for the inlet boot. stopped it at 3.2v so i rotated the clamp and it went to 3.8v then i bent the stop.