2000 Monte Carlo hard starting /stalling

[GLHT86]

Hi everyone
I have a 2000 Monte Carlo with the 3.4 V6 and lately the car has trouble starting and when I am driving down the road,sometimes the SECURITY LIGHT will come on,followed by the rest of the dash lights and stall,and then it takes awhile for the car to finally start up after cranking it.Sometimes it will backfire through the engine before starting.scanned and got trouble code P0102 MAF low circuit input.Cleaned out the MAF sensor with MAF cleaner,reinstalled,cleared the code and the car still hard to start and stalls.Rescanned and did not find anymore codes.What is causing this?Bad fuel pump?I just replaced the fuel filter and Air Cleaner also.Anyone else expience this with there Monte Carlo??Any help would be appreciated.

[GLHT86]

I also noticed too that sometimes the radio will read "Cal Err" while starting.This car has me stumped and I dont want to go swapping alot of unneccasary parts.

[Schrade]

Check your fuel pressure youtube 'fuel pressure test'.

Any loping at idle when warm?

Check at night, engine running, fully warmed up, for arcing spark plug wires. Solid state sensors are sensitive to radiation from bad and misrouted spark plug wires.

[GLHT86]

Thanks!I'll check the fuel pressure tommorow.No,there is no loping at idle.It idles smooth and not erratic at all.It just seems to have a hard time starting sometimes and then it stalls,even at acceleration.When I turn the key to start it,I can hear the fuel pump buzz on.

[GLHT86]

Well,I didn't do a fuel pressure test today,but I will do it tommorow.I drove it today and it was difficult to start again and again it stalled.It stalls with no warning,just completely cuts off.
I forgot to mention that the fuel filter I replaced it with is a Autozone one.Would this cheap filter cause all this?Again,I checked the MAF sensor,scanned it again,and no codes.The car also had weird stuff happen to like my domelight fuse blowing and ABS light on,that seemed to magically disappear.Again,very stumped!

[Schrade]

Originally Posted by GLHT86

Well,I didn't do a fuel pressure test today,but I will do it tommorow.

Post back results!

[GLHT86]

Ok,a little update.I mentioned that sometimes while driving,the security light will come on and then the car will stall.Well,I found this interesting article and wondering if my car is having the same problem.

Security Lamp Illuminated on the IP, Engine Stalls, No Start, DTC B2960 (Security System Sensor Data Incorrect but Valid) Set (Inspect and Repair Cause of DTC B2960) #01-08-56-002A - (Jun 19, 2001)


Security Lamp Illuminated on the IP, Engine Stalls, No Start, DTC B2960 (Security System Sensor Data Incorrect but Valid) Set (Inspect and Repair Cause of DTC B2960)
1999-2001 Chevrolet and GMC C/K Pickup and Utility Models (Silverado, Sierra, Tahoe, Suburban, Yukon, Yukon XL)

This bulletin is being revised to add information on inspecting for electrical intermittent conditions and important connector C201 tightening steps. Please discard Corporate Bulletin Number 01-08-56-002 (Section 08 -- Body and Accessories).

Condition
Some customers may comment on the following conditions. These symptoms may be intermittent.

• Security lamp illuminates while driving. The Security lamp may be On or Off when the customer brings the vehicle to the service facility.

• The engine cranks but will not start and the Security lamp is flashing.

• The engine starts then stalls and the Security lamp is flashing.

Cause
Condition(s) may be due to an incorrect Passlock™ sensor voltage received by the body control module (BCM) from the Passlock™ sensor due to the following conditions. Most intermittent conditions are caused by faulty electrical connections or wiring.

Would this be the problem?Im going to go ahead with a fuel pressure test,but it seems odd that my "Security" light comes on before the car stalls.And why havent I gotten any DTC codes on this??I'm going to investigate this further

[GLHT86]

Ok,I know the article is for GM vehicles other than my Monte Carlo,but I also found other articles with Monte Carlos having similiar issues.

[GLHT86]

Ok,I finally did a fuel pressure test.
Key on(engine off) 50psi
Engine On(at idle)Needle fluctuates between 49-50 psi
moves up to 58-59 when I open the throttle ,then drops back to 49psi and continues to fluctuate between 49-50psi.
Manual shows
Key on(engine off)52-59psi
Engine on(at idle)52-59psi
When I shut the motor off for awhile,drops to 39psi

[Schrade]

Originally Posted by GLHT86

Ok,I finally did a fuel pressure test.
Key on(engine off) 50psi
Engine On(at idle)Needle fluctuates between 49-50 psi
moves up to 58-59 when I open the throttle ,then drops back to 49psi and continues to fluctuate between 49-50psi.
Manual shows
Key on(engine off)52-59psi
Engine on(at idle)52-59psi
When I shut the motor off for awhile,drops to 39psi

Good job. Fuel pump is ok, and the fuel pressure regulator is responding to engine vacuum, so it also is good.

connector C201 tightening steps

I missed this. You need to get a printout from ALLDATA, or Mitchell's online, or the dealer or a shop, that shows where this wiring harness connector is. You might be able to google the location if this connector on your car.

Once you find it, you might be able to wiggle it in your driveway and make the motor shut off. Then you found the problem... Try the local library too...

[GLHT86]

chec,thanks,
So hopefully the fuel pump and regulator are good.I read the connector C201
is near the I/P?Does this go into the BCM module because I found that.I will look at that tommorow.Thanks!

[Schrade]

Originally Posted by GLHT86

chec,thanks,
So hopefully the fuel pump and regulator are good.I read the connector C201
is near the I/P?Does this go into the BCM module because I found that.I will look at that tommorow.Thanks!

Did you read and follow the instructions for Passlock diagnostics? I didn't read it.

If diagnostics are there, follow them to a 'T'. Skip NO steps. If you get stuck, you probably cannot go to the next step.

I don't know where this harness connector 201 is. The shop manual will show it in a schematic.

You MIGHT be able to find the connector by following the wiring harness FROM the distributor (ignition control), back to the BCM, if it follows that route.

Possibly when the Passlock voltage changes and kills the motor, it is because the BCM has sent a 'kill' signal to the ignition [process]. And I presume that's when the BCM lights up the 'Security' light.

I'm not familiar with this service issue. You're gonna' have to educate us as you do the research, and the fix...

[GLHT86]

Hi,people a little update

Finally determined the PCM was faulty.Took it to the shop and they also confirmed PCM.They replaced it with a new and reprogramed PCM and 1 week later,the car started stalling and hard starting again.We took the car back
yesterday and they confirmed the following codes

U1016
P1626
They told me they have no clue what is causing this.We are now out $600 and they tell me they don't know what to do.
I do not accept the "we don't know what to do" excuse because for $600 ,we expected the car to be repaired correctly.
I am now thinking of finding a way to completly bypass or disable the Passlock system.Any ideas would be helpful.

[gkbschevys]

I had the same problem and found that my fuel regulator was leaking by allowing gas into the vaccum lines. Shop replaced mass air sensor, oxygen sensor and some other sensor I beleive mapp. I found the fuel pressure regulator to be bad by reading on the forums. That's how I found out about this site. Check by cranking car and removing vaccumm line at regulator and see if gas is blowing by. A good indication is the the rubber boot is cracked from being exposed to gas.

[kavinder]

Hello.

Just wondering if you managed to get the problem fixed. Ive been having the exact same problem as you and at my witts end. Pulling my hair out in frustration. Have replaced the ECM, MAF, Temp Sensor, Fuel pump relay, crank relay so far. Any advice would be much appreciated.