I got the GTA running today! The fuel pressure regulator was bad and I wasn't getting good seals at the injectors.
It idles like a dream. When I step on the gas, it bogs down to the point it wants to die, then kicks in when I've got it floored. I did look thorugh my "Trickster pages" and found that a bad alternator will cause this problem. I tested it and found that it's not charging whatsoever. I tested the battery with the car running at 30 second intervals and watched the voltage drop from 12 all the way to 10.5 in only two minutes.
The good news is that it's running. I finally got it to the point where it'll idle until I shut the key off....or at least till the battery drains out. I had it running 20 minutes earlier today before I cut it off.

I scanned it and this is what I came up with.
Knock Retard = 0 degrees (jumps to 3 degrees every now and then)
IAC = 156 steps (decreases as engine runs, then goes back up again like it's slowly oscillating)
Coolant Temp = 163.8 degrees
Injector Pulse = 1.4mS
Desired Idle = 687 rpm
Start Up Coolant Temp = 146.3 degrees (had to restart since it died when I hit the gas)
O2 Sensor = ready
Engine Run Time = 181 seconds
Engine Load = 35
TPS = .62V
MAP Sensor = 2.03V (even though I don't have one)
Manifold Air Temp = 105.8 degrees
Engine rpm = 672
CCP Purge = off
MAF = 5 gr/sec
EGR Duty Cycle = 0%
Vehicle Speed = 0mph (duh)
Air Divertor Solenoid = off
CCP Duty Cycle = 0%
O2 Sensor = 24mV
Air Switch Solenoid = off
Shift Light = off
Battery Voltage = 11.8V
O2 Cross Counts = 4
Learn Control = Disabled
TCC Status = not locked
Fuel Pump Sensor = 11V
Block Learn = 128 (increases as engine runs. at 60 seconds, it said 30)
Rich / Lean = lean
Spark Advance = 15.7 degrees
BLK Learn Cell = 0
Loop Status = closed
Knock Sensor = 221
Integrator = 134

I am getting a code 34. The MAF doesn't pull down the 5 volts like it's supposed to. I need to replace it.

This scan was done after setting minimum air to 450rpm. How in the world do I adjust the IAC counts without changing the minimum air? Shouldn't I be looking for somewhere around 30-40 counts?

How does everything else look?

 

Are you sure you don't have the air intake stopped up with something? That IAC and MAF reading is telling us something along with the engine not revving up. I'm not smart enough to know what is going on but I think the answer is in there though.

 

The big noticable problem is the bad alternator...replace that 1st. You ever have another car with a bad alternator?

It runs until you hit the gas and then there isn't enough voltage for a good clean spark and the other EFI requirements.

Don't bother troubleshooting anything else until you replace the alternator with a good one.

 

The alternator is the first thing to get. I'll be buying a new MAF too. I unplugged the MAF that's on there now and it won't bog unless I hit the gas quickly. When I slowly push the pedal down, the RPMs rise nice and smooth.
Trickster's book says that the bad alternator can also cause this type of hesitation. I'm buying the new alternator first. Something tells me that's the root of the problem.

Tom3, the intake's free and clear. Nothing's blocking it up.

 

Hello Red,

I noticed your comment off to the side of the MAP voltage. If you are using an Auto X-ray scanner, it will list the MAF voltage as MAP because they use a generic parameters in their scanner software. I asked their head technician about this and he said they didn't want to pay GM for the rights to use their coding so they wrote their own.

 

If the ECM sees a lower voltage it will add more fuel. Like others have said get the alternator fixed and figure out the code 34. Did you replace relays yet for your MAF and MAF burnoff???? If not, try to unplug both relays and switch the plugs. Both relays are the same so you will not be hurting anything, but if its a relay acting up you should now get a code 33 instaed of code 34. It might help narrow it down before you dunk a bunch of money on a MAF sensor.

 

Yeah, both relays are new. I replaced them along with the spark controller and fuel pump relay sometime last year. The MAF's doing the same thing it was doing before I replaced them.

Trickster, I'm using an Auto Xray scanner. Is the 2.03v reading good or bad?

 

With a low air flow through the MAF you will see a low voltage. As the air flow increases, you will see a higher voltage close to 5 volts. So at idle that is about right although it probably should be just a tad higher. At the moment, mine reads 2.94 volts, 8 gr/sec, 12.8 volts at fuel pump, 13.1 volts at battery, 6 steps IAC, and 654 RPM at idle. I also have my TPS set at .54 volts.

 

Cool. That gives me a general idea what to look for.
I'm going to get this alternator replaced first and go from there.

BTW, have you finished putting that book on CD yet?

 

working on the menu for it and scanning three others. :lala: :lala:

 

Did you get this problem sorted?