Chronic Stalling Problem 93 Beretta

[Money pit Beretta]

Your CTS readings are strange. I forget what the defalt is, but you could locate it and unplug the wires. A bad CTS can cause a rich AF mix and if it's too rich it will stall. Sure seems to me that you are getting too much fuel. The fact that you had to adjust the throttle stop tells me that it's getting too much fuel. Really that is a "no,no". Adjusting the throttle stop is the wrong thing to do and can make things harder in the long run. I understand that you just need the car to run though.
Later on you may need to do a idle relearn(after the problem is fixed). Or a "reboot" of the computer(unpluging the battery for 10min).
Your MAP and O2 can be ruled out now. That IAT reading is also strange and it may need to be replaced. You can unplug that(not at the sametime as the CTS) and see if that makes a change. A bad IAT could cause a rich or lean AF. It tells the computer the air temp and the computer will adjust the AF to meet that temp(to get the correct AF ratio). The CTS does the samething more or less but with the coolant temp.

[3X00-Modified]

Guarantee its the coolant temp sensor. Anytime one reads -30 the car will run like crap.

[Wisconsinite]

I have some data on the fuel pressure. I got the loaner kit from Oriely's and hooked it in right after the fuel filter. While idling, the pressure stayed around 39 psi. I pulled the vacuum line to the regulator. The first time I did it the pressure jumped a bit, but when I repeated the test there didn't seem to be any pressure change. My book says the regulator keeps it between 34 and 47.. So shouldn't it be 47 with the regulator disconnected?

When the car is off and the key is turned to on, the pressure rises 5-10psi with each 2 second burst from the pump. It did eventual reach 47 psi after I turned the key on and off several times.

The pressure holds when the car is off.

Is this helpful? Any other tests to try while I have the tool?

[Wisconsinite]

I bought a coolant temp sensor, but it is a two-pin. The only one I can find on the car is a four-pin. I might need to order the right sensor. The book shows two, one to run the dash gauge, one for the computer. Maybe mine has one sensor that serves both?

It runs even worse when that is disconnected.

[Money pit Beretta]

The pump should run for just a few seconds and then quit(just the key on). That should give you the correct psi for a start. As for that correct psi I don't remember.
You will need the right sensor, if you are having trouble try to find it on Rock Auto.

[Rettax3]

I have some data on the fuel pressure. I got the loaner kit from Oriely's and hooked it in right after the fuel filter. While idling, the pressure stayed around 39 psi. I pulled the vacuum line to the regulator. The first time I did it the pressure jumped a bit, but when I repeated the test there didn't seem to be any pressure change. My book says the regulator keeps it between 34 and 47.. So shouldn't it be 47 with the regulator disconnected?

When the car is off and the key is turned to on, the pressure rises 5-10psi with each 2 second burst from the pump. It did eventual reach 47 psi after I turned the key on and off several times.

The pressure holds when the car is off.

Is this helpful? Any other tests to try while I have the tool?

Try revving the engine hard while reading the pressure. 39 PSI isn't very healthy, but it shouldn't cause the car to be undrivable either. But if the pump is weak, then the pressure will likely drop while the engine is under load. Your regulator could also be causing the lower pressure, if the spring has become weak, and it is a whole lot easier to replace should you decide to, but the lack of pressure rise the second time you pulled the vacuum-line off tells me that 39 is simply all that your pump can produce anymore. Of course, we are also trusting the gauge to be accurate, and your reading is so close to the minimum... Well, we work with what we have, right?

For the coolant sensor: I have done very little with the 2.0 and 2.2 Berettas, so I cannot swear to it, but I think you have just the one sensor, especially with it having four (!) pins.. I don't think I have ever seen a four-pin GM temp sensor before; they are typically one (usually for gauges), two (for gauges OR ECM/computer signal) or three (for both gauge AND ECM). On the older Berettas (pre-'91), the only cars I'm aware of that had only one sensor were the digi-dash cars, and they were all V-6 powered. But anyway, the newer ones, like yours, may just have the one sensor. That was all my '95 3100 Beretta had, and aside from the '96 cars, and the option of with or without tach and 4-cylinder or V-6 calibration for the same, all the newer gen Berettas had basically the same instruments. I checked around a bit on Rock Auto, and I cannot even definitively find a four-pin CTS for a Beretta... Have you found a source for a new one?

[Wisconsinite]

Another day working on the beretta..

I left the pressure gauge on overnight (rained a bit, but the gauge was in a rag under the car). Yesterday it was reading about 40 psi, now while idling it slowly creeps up to 30.

So either the car had better pressure yesterday, or the gauge is reading lower than actual pressure. I pulled the gauge off and tested it on the air compressor tank, and it matched the compressor's built in gauge perfectly. So, the car has terrible fuel pressure!

I uploaded a video to show what I'm looking at. Can anyone confirm that I have correctly identified the CTS?

http://www.youtube.com/watch?v=8TPQgYJv ... ata_player

After the video I sealed the leak, but while idling it still only got up to 30psi. For a while it read near 0 psi while idling.. Is it even possible for a car to run on that little?

If it is the pump I might take it to the shop. Removing the gas tank doesn't sound fun. But it could be a relay or wiring issue, right? I'm sure someone on this forum has started a thread about testing fuel pumps, I'll see if I can find anything.

Thanks again, everybody. Seems like we are making progress!

[Asylum]

I think you may have two issues.
The CTS and perhaps a wonky regulator.
I think '93 still had the fuel pump test wire over by the inner fender on the Driver's side, but someone else will know for certain.

Good luck with it.

[3X00-Modified]

That CTS I can't find anywhere for a 93, but that's definitely it... I found that plug listed as a ACDelco PT149 Engine Temperature Sensor Connector, that fits 92 and 93 2.2L engines... VERY odd...

As far as the pump, if there is no leaking then you should read full pressure at key on engine not running, and yes it may drop a bit but shouldn't drop quickly. An engine will run with 10 PSI of pressure too but you will have to give it throttle to get started.

SO I'd start with the pump and then try to source a sensor somewhere for the coolant... And I have no suggestions there... Checking GM parts direct now to see if I can even get a PN.

[Wisconsinite]

I jumpered a wire from the battery positive (through a 10A fuse) to the grey wire at the pump. I can hear the pump running, but it took 30 seconds to get the pressure up to 30 psi. I'd like to rule out the regulator.. Is there a way to do that? Or is pressure this low only possible with a bad pump?

My only idea was to clamp the return fuel line after the regulator and see if the pressure is still low with the pump on.

[3X00-Modified]

No dice on GM parts direct... also checked a Fan sensor and nothing similar looking came up... I'm a bit stumped on that one.

Clamping the fuel line may not give you the best result, but it would let you see how quick it rises... don't concentrate on the end pressure but more of how quickly it gets there.

[Wisconsinite]

Yeah, that sensor is odd. I thought it would be on the next year or something, but I can't find any 4-pin temp sensors for any berettas.

I'll try to get the engine code, maybe that will shed some light on the issue.. The other route would be to install a 2-pin temp sensor and wire it to the 4-pin harness in such a way as to fool the ECU. I measured 1300 Ohms across two of the terminals with a fairly cool engine. I could test it at various temperatures to determine if it is working, and which wires feed info to the ECU.

[3X00-Modified]

I am guessing the other three pin sensor you found feeds the ECU... A typical dash sensor is only one wire. I think that sensor at the thermostat is a fan turn on only.

But I could be wrong.

[Wisconsinite]

With the return line clamped, the fuel pump still took 15 seconds to get 20psi. It couldn't get the pressure above 35psi at all.

This pump is definatly bad, right? Or could the 1 year old fuel filter be clogged bad enough to do this?

[Money pit Beretta]

I'm giving the fuel pump the evil eye.