Oil pressure drops to zero, Car stutters and turns off

[Coryjames]

Hey guys, first of all I would like to thank you guys for years of useful advice and instructions for keeping my Pontiac alive. I probably wouldn't be driving her if this website didn't exist.

Here's my issue. This morning I started my 1995 Pontiac Bonni SE and got her onto the freeway, suddenly my "check Gages" light starts blinking, starts making the check lights sound, and then I see that my Oil Pressure gauge has drop completely into the red zone and my engine starts stuttering and then stalls.

I checked my oil (was pretty low but I filled it back up to normal), my coolant (seemed normal), and if anything was leaking under my car (nothing more than the oil leak that has been there forever). I then got back in the car and restarted it; The pressure gauge and everything sounded and looked perfectly normal for about a whole 5 seconds, then the gauge suddenly dropped to red and the car shut itself off.

Fortunately a highway patrol officer pushed my car off the freeway and helped me get some oil to refill, I added the oil and it made no difference; this time the car wont even start (it does turnover perfectly fine though).

I have had a typical wal-mart high mileage service with 10w-30 oil about 3 weeks ago and have driven it plenty since. However before the car was primarily driven by me, my father used to put 10w-40 in it saying he does that just because of the mileage of the car. I'm not so sure if that's of any significance or even a good thing.

Other than that the car has been pretty normal. In the past 2 years I've replace the Brake master Cylinder, replaced spark plugs/plugwires, clean the MAF sensor, replaced starter motor, replaced IAC valve, and a couple of minor thing.
From what I have read so far online is that it can either be my engine, my oil pump, or my oil sensor. I'm leaning toward the sensor since my engine has sounded and behaved fine since I fixed a misfire 5 months ago and also because the oil pump itself is apparently all but indestructible under 200k miles and decent treatment.

I need this car repaired as fast as possible so I can go to college and keep visiting my family. Any help on what it could be or what I should do or check would be greatly appreciated.

[J Wikoff]

I'm trying to remember if a bad oil pressure sender can make the engine stall. I don't recall if it was obd 1 or 2 that had a link to the fuel pump.

[Coryjames]

Well I had it taken to a mechanic and he is running a diagnostic on it, he doesn't seem to think it has anything to do with the oil pressure. I think that this year of Pontiac has the kind of OBD that was between 1 and 2 so I've never been able to have anyone scan it.

[KM AXer]

Will be interesting to find out what your mechanic discovers.
Although I am not a fan of swapping out parts, hoping that a puzzling problem is somehow cured, I'd be spending the few bucks and installing a new oil pressure sending unit. Not expensive, and a good first measure.

[Coryjames]

I am not fully involved in whats going on with the car since my parents took over. But what I have heard just now is that the mechanic put about $650 worth of time and parts into the car and was still not able to figure it out and says that all it could be now is some computer part that apparently costs $1000.

As much as I would have investigated this myself and see what he is talking about and has done to the poor car, I really don't have time.
So pretty much now my question is, what is this mechanic mechanic talking about and is there really something worth $1000 that would do this to the car?
(it apparently wont even turn over now).

Is this car pretty much scrap now or is this mechanic just really bad or dishonest? I almost feel as if he's scamming my parents.

Anyway, I'm pretty bummed about my car she was good to me for a long time. So and any feedback would be nice, even if its bad. I'll provide more details about what he did and what he said when I find out.

[KM AXer]

A simple question:

When you say that "the car shut itself off", do you mean to say that the engine seized, or just that the fire went out, and the crankshaft rotated to a stop because of no explosions in the cylinders? Huge difference.

By "won't turn over", do you mean that when the key is turned, the starter will not even spin the crankshaft?

[Coryjames]

The engine did not seize, it rolled to a stop as if it was having trouble getting gas or no spark. I am not sure of its condition right now, specifically if the key is turning it or not (I didn't hear that straight from the mechanic). When I last had it at the mechanics shop the day it died it would still start but then turn off after 2 seconds or so; just like when I was on the freeway.

I was able to do a little research today and i'm wondering if this could be the ICM or PCM.
I actually have a ICM I took from a 2001 bonni at a junk yard a few months ago when I was trying to fix a misfire.
The engines were the same so I'm hoping it will be compatible.

The ICM in my car was pretty trashy looking and covered in oil, and the wires connecting to it were baked and the isolation was crusting off.

I should have thought about this awhile ago, but more opinions would be good.

[RJolly87]

http://www.pontiacbonnevilleclub.com/fo ... 17857.html

Motherload thread on that subject of the oil pressure sender and the fuel pump.

Running for two seconds and then shutting off has me suspecting the fuel pump is priming, but not being commanded to run.

And when it died, did the oil pressure drop, and then the tach dropped to zero? Or did everything drop to zero at once?

Also, what is the security light doing on the dash, or does it even have one?

There is no way to tell if the mechanic is scamming without knowing what is going on. Also, being a '95, the mechanic needs to have a scanner that can read OBD 1.5 to read data, which is fairly uncommon.

Also, a $1000 computer sounds about right if he is ordering it straight from the dealership, overnighted from Antarctica, and then gold plated before installing. A new computer at Autozone for example is $150 + $100 CORE. The choice plan of attack is to get a computer from a junkyard. It really sounds like the mechanic is just flying blind on your dime at minimum however.

[Coryjames]

Hey RJolly87, the only gauge I notice move at all was the oil pressure. The others stayed about the same but I do not know about the tachometer. I probably would have noticed if it was jumping though since I've had experience a crankshaft sensor dying on me once.

Also, I didn't see a security light doing anything; I'm not even sure if it has one. The only light different light I saw was the "check gauges" light.
Another piece of information I can provide is when I was having it towed behind my friend truck; when ever I have the key on and when the car would roll it would periodically beep a bunch to tell me to check my gauges. I actually turned my car completely off just so it would stop beeping at me while being pulled.

And yeah, I would only want a gold plated computer from Antarctica. But before I start switching part arounds, I was wondering how I could test which computer it could be before I start switching things out and getting a PCM from the junkyard. If it even is a a computer anyway. is there anything else beside the PCM and ICM that would do this?

[Boreas]

Was the fuel pump ever checked?

[Coryjames]

Solution: Fuse and a bad PCM (or ECM).


We had it taken to a new mechanic who happened to have a OBD 1.5, he was able to find the blown fuse and bad PCM on the spot. He first replaced the fuse and the car would run very rough. Then he replaced the ICM and it would run decently again. It was really awesome to have a mechanic that was really friendly and knew what he was doing.

However, my car runs but there is a very noticeable growl now that echos through the car during some speeds and RPMs; especially while at a complete stop in drive or neutral or park. I'm not super worried about it right now as long as she continues to run good. I may make a new thread about it someday if I get spare time and if it gets worse.


Also if anyone is curious, here is a list of what parts were replaced. I can't believe the first mechanic didn't find that fuse. I guess the moral of this is check your fuses and find a good mechanic. Now we're $1000 short and I have a bunch of spare parts I'm not entire sure what to do with. I'm kind of curious what you guys think about all of this.

Mechanic 1:

Crank Shaft sensor (which was recently replaced already)- $45
CamShaft sensor - $40
Fuel Filter - $19
Fuel pump and intake Filter - $162
labor - $375

Mechanic 2:

New PCM and Labor - $300

[KM AXer]

Glad to hear that it is running again!

Just a suggestion:

Whenever I find someone exceptional in a trade that others might also need, I let people know about him or her.

In this case, it seems as though you have found a guy who can do a good job helping owners of similar age cars keep them going, without wasting time and money.

So, how about posting the name of the shop and the mechanic, along with the location? Guys like this are much more rare than people realize.

[Coryjames]

Of course, thanks for the recommending that.

The mechanics name is Chris at HillTop Auto Works
1775 South State St.
Orem, UT 84097
http://www.hilltopautoworks.com/

They also towed me from my first mechanics shop for a decent price.
I am going to end up writing him a review online.