Code 33 - new member

[PaulyG123]

Hi all. I'm new to this board and was wondering if I could get some help. I've got a '91 Lumina 3.1 coupe which has been giving me a strange problem. After short runs, once it's warmed up, if I shut if off it won't start. I've run the code (by shorting pins A and B and counting flashes) and have come up with code 33, MAP sensor. I've replaced the sensor, and still get the same problem and symptoms.

 

I've, unfortunately, spent a lot of money fixing up quite a few problems:

rear brakes and calipers; front pads and rotors; new plugs, wires, coil packs; new fuel injectors; power steering pump; new wheels and tires (American Racing rims, 215 60/15 Goodyears); and a lot of basic maintenance stuff.

 

I'm gettin' tired of being nickle and dimed to death, and just want to get it running so I can sell it off.

 

Any help would be appreciated.

Thanks,

PaulyG

[Slade901]

Check the vacuum hose on the map sensor.

 

When you said that the car won't start again when it is warmed up, does it just turn the engine (but it won't run the engine) or the engine won't even turn when you try to start it.

 

If the engine does not even turn when you try to start (engine is still warm), then it could be your starter solenoid that is failing. When the starter/starter solenoid gets hot (engine heat), the starter solenoid will not get the right voltage to turn the starter itself. When the engine bay area cools down then the starter solenoid will start to function again and able to turn the starter.

 

I've encountered this problem before and cleaned the starter/starter solenoid because there was a lot of oil covering it. Found the source of the oil leak that was dripping down the starter/starter solenoid and fixed that oil leak and I also purchased a starter/starter solenoid heat shield (blanket type).

[PaulyG123]

Starter's fine. The engine cranks, but won't turn over. It sputters and sometimes starts, but idles really rough before stalling again. It seems like something needs to cool off before it'll run right again.

 

Thanks for the quick response.

PaulyG

[Slade901]

Try starting the car without the O2 sensor and see if it stalls or not..

Possible clogged cat..

[GnatGoSplat]

It could be a leaky vacuum line to the MAP. You can try spraying carb cleaner (or I've heard WD40 works too) around all vacuum lines and see if the RPM's change or the car dies. If it does, you definitely have a vacuum leak.

 

If you're convinced there are no leaks and the MAP sensor is good, then the only possible outcome that I can think of is the ECM has gone bad.

[Robby1870]

Heres a test I do for a bad vacuum line for the MAP. Start the car, and take off a vacuum line you know works, like one that goes to the Charcoal canister purge solenoid. Put your finger on the end of it and feel how much vacuum there is at idle (should be like 14-15lbs, if you have a guage), then do the same on your MAP sensor vacuum line. If the MAP vacuum has less vacuum, theres your problem. The vacuum line to the MAP is that branch off the fuel pressure regulator. I'll tell ya what I did. I by-passed the stock placement for the MAP vacuum line, I ran a T off the fuel pressure regulator line, the ran a piece of normal vacuum hose (not the hard plastic stuff) around the back of the motor to the MAP. Makes it so much easier to take on and off. Just some suggestions

 

Robby

[PaulyG123]

Thanks guys. I'll try your suggestions the first chance I get.

 

PaulyG