I just purchased a 94 Park Avenue with the OBD 1.5 setup. The engine (non supercharged) and transmission work great, but there is a serious stalling problem. Here are the symptoms:
* When I start it up in the morning, it will run fine for about 5 seconds and then just die. It will die again for 2 to 4 attempts and then start fine and run fine.
* I will die again about 2 miles from the house, but will start right back up and run fine.
* It will go another 5 miles or so and die again, no matter what speed I am going. It will stall under any throttle condition. When it stalls, I can feel the power go away even though my foot is still in the throttle.
* After that, it may go 20 miles or so before the next stall. As the stalls become less frequent, the engine may not completely die, but it loses all power and stumbles at about 1000 rpm. I cannot rev the engine when it is stumbling.
* Finally, it quits stalling and will run fine for a long trip. We drove it from Des Moines to Kansas City and experienced about 10 stalls. We drove on to New Mexico (1000 miles and 3 days) and did not have another stall.
* After sitting for about a week, the stalling symptoms returned.
* I do not have a check engine light or access to a scanner.
* The crank and cam position sensors were recently changed.
* I changed the fuel filter (the old one was clean).
* The air filter is new.
*The engine surges just a little while it is idling, but I'm not sure if that is normal or not.
* I cleaned the throttle position sensor, although it looked perfect.
* The engine is very clean and well cared for. The odometer reads 60,000 miles.
It seems like a gas problem because it just quits making power with no surges or coughing. I am baffled as to why it starts right back up and runs so well.
My best guess is the fuel pump is bad and does not pump reliably after setting a while. Once it gets going, it loosens up and becomes more reliable. Sadly, my fuel rail does not have a test port on it so I will have to rig something?

This is an unsafe situation! I spend all my time in the slow lane, and I hate white-knuckling!
Has anyone seen anything like this? Some suggestions will be greatly appreciated.

Steve

First thing I would check is the fuel pressure. You should have around 48 psi. If not, then your fuel pump is dying.

I have been pulling my hair out with similar symptoms. Except the stalling started far apart and warm engine, then became more frequent and more off time before starting. Now, a cold engine will run anywhere from 2 seconds to 15 minutes then shut off.

I bought this '93 Century 3300 MPFI V6 a year ago with 68K miles on it (truly an "old lady - garage find"), it ran trouble free for over 6 months, then this stalling at intersections and nearing the top of a mild hill started. Being a 1980'* 3.8 fan, this 3300 was my new hero and I was enjoying working on it until this stalling started. Now I want to blow a hole in the block! LOL Unlike Steve'* car, I can't trust it to make it to the end of my driveway, let alone to the end of the block. It got so bad I had to tow the car home. But it will sit here and run smooth as glass 15 minutes in park... sometimes.

In the beginning it felt like the running out of gas sputtering (that'* when I changed the filter). Then the instant turning off the key stalling started. The engine always runs full power before stalling. I have replaced fuel injectors and filter on previous tune-ups. I tested the fuel pressure and fuel rail regulator. As Steve said, it'* just willie-nilley now; no rhyme or reason.

It only threw a code 21 which is low TPS setting and I tested the potentiometer with a multi-meter (there is no 'gone bad' code. 21 is low idle voltage and 22 is high idle voltage. It'* an 'out-of-range' code). For kicks I did replace the TPS and set the voltage to the specs. I replaced the fuel relay behind the headlight and cleaned the MAF and that other motorized idle plug thingy (see? I don't know all the acronyms hehe).

All that'* left is the Ignition Module and Crank Sensor.... riiiight? This car being a Buick, I am so lost on this needing a "special" $300-700 alignment tool that is basically a piece of plastic. But more than one forum said attempting doing it without a tool is very risky at best, but it can be done. I'm searching for a parts store that rents this tool as we type.

It drives me nuts that it'* not showing any other codes. Yes, I cleared it twice for good measure and the car has ran 2 times for 15 minutes. No new codes are being tossed up.

Now for my questions to those who might know...

1) In my old school experience, I know the ignition module will just go out all together or one coil at a time. I have talked to people at various places that tell me that the transistor modules wont pull an intermittent on you. Once it'* dead, it'* dead. --- Then I get to some blog that says intermittent problems like this is a classic ignition module problem. Okay I know the old school modules went dead and that'* it, but what about the new modules under the triple 3300 V6 coils? CAN they give you intermittent problems?

2) Can the CPS give you an intermittent problem or does it just go out permanently.

ok, 3) Since I'm not getting any new codes, can these things go out and NOT throw you a code?? I know early OBD is not that great, but can it be totally useless in these areas?

The CPS can fail in stages. When mine went, it would stall once in a while and start right back up. After a while it would stall more often, but still start right back up. Eventually it would stall frequently, and I sometimes had to let it sit a bit before it would start. This all happened over two months or so. It did not set a code.

The only thing not consistent with a CPS issue in your description is it will not cause your car to sputter. When you have a CPS issue the engine shuts down like a switch was pulled.

I am not familiar with your engine. What is this device you need to change the CPS? On the 3800 all I needed was a puller to pull the harmonic balancer.

on my old 3100 which i would assume would be the same, its a hall effect sensor that is on the firewall side above the trans. no special tools that i know of. mine went out in a similar way getting worse and worse. the ign module just made it completely die one day.

Oh wow, Looky what I found!

1) https://www.gmforum.com/mechanical-134/pulley-change-index-285990/
(scroll down and click on #6)

2) https://www.gmforum.com/mechanical-134/change-crankshaft-position-sensor-279066/
(found this one almost near the bottom of the pulley page)

Amazing what you find when you look around. Funny thing is I was lookin for a CPS article and it was hiding behind a pulley article. Here is the two links that tell you 1st how to pull the balancer, then 2nd, the CPS it'* self.

2kg4u.. the special tool is an alignment thingy you need to set the gap between the sensor and the pulley so it doesn't crash into the steel fins. BUT not on the 3300. This engine has a plastic collar that you bump the CPS up against and tighten it. There is no space to gap. Here is the article for the tool, its apparently used on a 3800.

https://www.gmforum.com/1987-1991-93/crank-sensor-without-alignment-tool-207656/

as I found out all I needed was just a normal puller with custom bolts, the article above tell you to get 1/4x28x4 inch bolts. I find that on the Century (same body as a Olds Cutless Cierra) the sheet metal in the fender well hangs a little low and blocks a 4 inch bolt. 3 inch bolts were perfect. 2½ will work in tighter situations but you will have the puller tight against the shroud. Also my puller had plenty of screw left when I used it with out the center bolt as in the article. I just sent the screw to the bottom of the empty hole.

There is an installer that has a bearing instead of using the center bolt alone. It makes it so when you torque it to 110 Ft#'* its a true torque. The washer is so large that some friction would lessen your actual pulling power and throw off your reading on the torque gauge.

It seems that the later model cars are doing this, using the starter ring instead of the harmonic balancer. Life would be so much simpler if they did this on all the cars. Hiding the sensor behind a pressed on balancer is akin to putting the oil drain plug inside the bell housing ::

You can rent a fuel tester kit at auto stores that loan stuff. Sometimes you buy it on a credit card and they refund it when you return the kit.

Inside the kit as a gauge that looks like an over sized compression tester. It has several adapters for each system. There is an instruction book and small, almost cheesey, but kinda nice multimeter in some.

With the adapters it will instruct you to remove the banjo bolt at the fuel filter or other connection inside the engine compartment and put the adapter inline, then attach the hose from the pressure gauge to the adapter.

Autozone in California "loaned" me the kit at $160 to be refunded upon return. I grew rather fond of the kit and decided to keep it. Since the world has gone EFI, whet the heck, I'll be needing it more often than not.

Here is a budget kit, but if you scroll down, you can see the more elaborate kits

http://www.harborfreight.com/fuel-in...ter-92699.html

it was on a 90 GP GT that i had, and i assumed that since the 3300 was a 60 deg v-6 too it would be the same, but its completely different. not sure why they would make it so much harder, but it seems every time i work on any 3300 they specifically stood back and thought "how can we make this the hardest engine to get to everything, ever".

Well I have run the tests according to the article at: https://www.gmforum.com/trouble-shooting-test-procedures-141/icm-test-299761/

My ICM plug has some wires that are not used and have rubber nipples sticking out to mark that the terminal is not in use. (Marked by blue font)

P-N-M-J-K-H (screw) G-F-E-D-C-B-A

I'm not seeing a Cam Pos. sensor, the car has no tach, etc. Having less wires does not throw me because I know a 3.3 is not a V8 Bonneville engine.

The only difference in the color code is the G position, what would be a yellow wire is really a dark blue with white stripe. But it goes to the same pin on the crank sensor. Just for fun, I did a continuity test on all 4 CPS wires and got a beep.

The third test is wire G I did get the 6.6v to zero volt alternating signal. So the 18X CKP test checked out.

One thing I noticed is the instructions have a contradictory element. On the 4th test, 3X CPK signal test on the H wire, it says you should see 5 or 6 volt difference as you rotate the crank. I do.

But if the answer was yes it says the ICM is bad and to replace it. That is confusing to me. It says that I SHOULD see 5-6V'* then says it means the ICM is bad. You can only have yes or no and both answers require changing a "bad" thing. So after you change the "bad" thing, wouldn't you still get a yes or no answer?

Me thinks this is a typo. I'm in a quandary over it. I need this car out of my driveway. lol

So now I have a new fuel filter, fuel relay & the fuel rail tests are textbook perfect, new TPS, new Crank Sensor, The MAF checks out good on the voltage and the tap test.

The car starts, runs for 3-30 seconds and shuts down.

Oh, and I went to a DIY junk yard and bought a used main computer with exact numbers and letters on the paper label. I mean there was not one letter or number difference. It was from the identical year car w/3300 V6, save it was a sedan not a wagon. When I cranked the motor, the engine stalled the moment I let go of the key like an old ballast resistor gone bad. I reinstalled the old computer and we're back to ground zero with my stalling symptoms of 3-30 seconds running, then kaput!