Beretta.net

I have a 91 beretta 3.1 liter v6. owned it for a year. for about four weeks now it's been idleing weird, stalling while i'm driving it and the check engine light comes on at random throughout these events. the best way to describe how it's acting when i'm driving it is like it totaly loses power like the engine is going to shut down, then it will kick back in over and over again. if i pull over the car will idle funny and sometimes stall or start running fine again. if i keep driving it just keeps jerking and stuff. found water in the gas but as far as i can tell i got it all out. changed the fuel pump. the air intake control, cleaned the EGM checked my plugs and wires, and also found a tiny vacume leak that's been fixed. no codes come up when we hook it to a computer because my check engine light won't stay on. I could really use some help I like this car and it would be a shame if i had to get rid of it.

Does it only stall when it's warm, or does it happen cold too?

nah it doesn't seem to matter weather it's been running or if it's a cold start, sometimes it will act up right away, and other times i could drive it all day then it would start acting up.

is it misfiring good well be a random misfire or injectors

It doesn't seem to be misfireing. it's not jerking around or anything anymore. now when you'll be driving down the road and the darn thing will just stall out, it's like the engine just shuts down. sometimes it will start right back up, other times it will leave you sitting for a bit, but adventually fire back up.

Try tapping on the ECM and see if it stalls or stutters.

If it only does this when it is warm then I would check the injector resistance when it dies, the ignition module, and crank position sensor.

If you have no tach signal wheh it dies then I would check the CPS first and the other stuff later.

Mine was doing the same thing as yours. Check you map sensor, it may not be getting proper vacuum, and also the crank shaft  sensor. Those two problems is what caused mine to do the same as yours

I dont know if you have resolved this issue with the car, but I can say that I have had the same issues with my '91 3.1L and they are (God willing) resolved.  I fumbled around for several weeks, but in retrospect, I can say that there were two sensors that affected the performance and stalling that you have identified: the Manifold Absolute Pressure (MAP) sensor and the Crankshaft Position Sensor (CPS).  I changed both.  Try the MAP first as it is located in a very accessible location on the firewall.  If that does not resolve the issue, try the CPS.  That is a very difficult item to replace.  I can help you with this one if you want.  But, that has been my experience.  I have a couple of messages on this board.  My computer was showing Code 22 and Code 34 for these issues.  good luck.

Where is the CPS sensor loacted and is it hard to replace? I have a 2.8 with a MAF sensor system doing the same thing and im thinking that this may be the problem, my tach goes all funny too, like suggested above. I've checked the coils, ok. I know its not water in the fuel and i even tried unplugging the tourque convertor lock up switch, because i ran into that problem on my last beretta, but still the same problem, it seems like my beretta is going faster on a hook lately than by its own power. LOL

ANYBODY ???

The crankshaft position sensor protrudes into the block about 2 inches on the firewall side of the engine.  It's the only other electrical connection on that side except for the knock sensor (on the 2.8 or 3.1)

Just saw your post GTZ.  Cliff told you where the CPS is.  I have a 3.1, so the config may be different.  To access mine, given that I have no hoist, I jacked the car up, put it on two stands and got under from front.  You need a light.  look up between the oil pan and the transmission pan.   You can reach up and get a couple of fingers on it, but since mine was in there for 15 years, it snapped off and I had to take off the oil pan to get it out.  Not easy.  if you want the gory details you can email me at    Tim othy @ Rog ers.com (no spaces in the email address).

This all sounds similar to the problem I am having with my 94 3.1 w/155K on it.  It starts and runs ok but starts cutting out at about 2500/3000rpm (60-65mph).  It stays running but starts shuddering until I slow down.  As soon as I go below about 2500 rpm, it goes away.  New spark plugs, overall runs smoother but no real change in the problem.  I am thinking fuel filter, mpfi or fouled CPS.  Any thoughts?