Beretta.net

Background
'91 Beretta 3.1L; 160Km (approx 80k miles).
Car was running very well but started to die intermittently. Had codes: 22+34 from computer: 22=TPS voltage low; 34=MAP voltage low. Don't ask me why, but I changed a bunch of sensord with new ones: new Crank sensor (CPS); new O2 sensor; new Idle Air Control Sensor (IAC). Car started right up and ran great for two weeks. Then one night after driving downtown a couple of weeks ago and getting hot, car died; difficult to start; stalling; cooled down; restarted; drive couple of km's, died; restarted; etc, finally got it home; read codes: 22+34 again!!
This time, changed the TPS and did some tests: fuel pressure check: 43 psi at rail; fuel lines and filter are only two years old, moderate driving; approx 11.5 ohms resistance on each injector; spark on front three cylinders confirmed. Therefore, I conclude that I have Ignition, Fuel and compression for ignition because the car runs, but I did not do a compression check.

Fired up car. Idles but revs high (approx. 1600rpm) and throws the nasty codes 22+34 again  When I blip the throttle, car dies. I have not taken it out to drive around cause of the above problems in my driveway. I should add that I have meticulously checked for ground faults and vacuum leaks. I found none.

Any thoughts experts?

You need someone with a factory service manual to tell you what the reasons are for 22 and 34 and check what is similar in those faults.

I gave my books away with my car.

Causes of code 22:

1.  TPS signal voltage less than .2 volt for 3 seconds with engine running
2.  Open or short to ground in GRY or DK BLU wire to TPS
3.  Short to ground in GRY wire to MAP sensor

Causes of code 34:

1.  Engine RPM is less than 600 and manifold pressure reads less than 13 kPa for 1 second
2.  Engine RPM is greater than 600 with throttle angle over 20%, and manifold pressure is less than 13 kPa for 1 second
3.  Intermittent open in GRY/RED wire or PPL/WHT wire to MAP sensor

Note:  If the MAP sensor fails, the ECM will substitute a fixed MAP value and use the TPS to control fuel delivery.

Guys: thanks for those replies.   I will f/up with some tests and let you know.  

Start checking resistance in wires to the TPS and MAP.  One of them should be a direct ground, one should supply 5 volts and one goes to the ECM and should not be open or  directly grounded.

Guys---problem solved --I think.

I want to thank Rex and Jeff for their suggestions. ÂÂÂ I replaced the MAP with a new one.  But...it did not immediately solve the issue. ÂÂÂ Still died. ÂÂÂ I reset the computer and then the car started and has been running for three days with no incident. ÂÂÂ The MAP was, apparently, bad, even though I tested it on the bench and it appeared to be good a couple of weeks ago. ÂÂÂ I will let u know if the situation changes. ÂÂÂ All the best everyone.

Point of interest for readers.  Before resetting PCM I was still trying to troubleshoot the issue so I measured the voltage at both the MAP and TPS (reference pin to ground pin).  It showed approx. 2.5v, when it should have been 5v.  I was puzzled by this but after resetting the PCM, it went back to 5v.  fyi.  maybe it is supposed to work that way  

Interesting, I hope you got it!

I'm doubtful on the resetting, but we can hope that fixed it.