GM 3.1l (3100) and 3.4l (3400) engine data sensor locations and descriptions.
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10. Egr Valve                        11. Intake Air Temp Sensor (IAT)      12. MAP sensor
Typical engine data sensor and control component locations on the GM 3.1 / 3.4 L V6 engine.
Click on number for a description.
12-21-10
I have a 2001
Pontiac Grand Prix that stopped running, I have put a new fuel
pump, and new computer box on it, but it still wont start. Can you help me,,
please, it is driving crazy
Comments
There are way too many things that can cause the car to
stall and not start. Do you have spark, fuel pressure,
injector pulse, theft or security light on dash, etc. You
need to start by diagnosing the basics.
4-24-11
I have a 94 Grand prix 6 cylinder engine. Car stared missing, was told it was EVAP purge
solenoid. Replaced it and drove fine for short time and problem started again and again
was told it was EVAP purge solenoid. Why is this happening over and over again. What
can I do?
The purge solenoid would not be causing an engine
misfire. It would cause a check engine light yes, but not
affect the way the engine runs,
7-7-11
try looking for a bad fuse in the dash or under the hood.
8-18-11
I have a 1994 Buick Century and in the last month or so the engine started making a noise
that  sounds as if it were literally was a diesel engine. When opening the hood one might
there was very little or no oil coming up to top end.   Thank You
It is possible you have low oil pressure, a bad lifter, or
more likely one of the rocker arm studs has pulled out of
the cylinder head. This would also cause a misfire on
that cylinder. Removing valve covers for inspection
seems the next step after checking oil pressure.
8-20-11
How do I remove the TPS shaft from the throttle body? It appears stuck from the right side
(as viewed from the drivers side). The little piece will not come apart on that side to
release the shaft.
If you are trying to remove the throttle plate shaft from
the body, it cannot be done. If you have a problem, the
throttle body needs to be replaced as an assembly.
8-25-11
i have a 2000 chevy impala that keeps saying low coolant level but theres no leak that i
can see and we changed the thermostat and reset the computer in the car and it still says
that, what could it be? The temperature sensor?
Cannot be the temperature sensor or thermostat. The
light say "LOW COOLANT". If the coolant is low, you
have a leak and need to get it inspected closely. If it is
not low, then you may have a level sensor problem.
8-31-11
I have a 2001 Olds Silhouette that needs the oil level sensor replaced....warning light
comes on every time you start the car but the oil level is full.
9-1-11
Before you change any parts, examine the wires that go to them. GM has had many
engine problems caused by the wiring. This is easily demonstrated when one or more of
the connectors related to the PCM is left unplugged. You'll get an error code for a bad
part, not a bad connection. Reconnect the plug, reset the code, and you don't get it again.
This is from first hand experience.
9-5-11
i have a 1999
Pontiac Grand Prix need to know where the low coolant sensor is. The light
flashed low coolant all the time and it has plenty of coolant and its not running hot at all.
9-27-11
i have a 2004 impala 3.4 it keeps shuddering and turn off.
The low coolant level sensor is in the passenger side of
the radiator. Below the radiator cap. It is a square black
sensor that snaps into the radiator and held with a clip.
10-1-11
my car idle is stuttering and my car shuts off at time.
10-5-11
I have a 2000 chevy impala and temp gauge rises to the red but I don't heard any over
heating or boiling noises but I do hear a kind of hissing noise. What could it be? The temp
sensor I'm guessing/
If the temp gauge is going into the red, it is overheating
whether you hear it or not. You'd have to try and find the
exact cause. It could be anything from a water pump,
intake gasket, head gaskets or even radiator.  I highly
doubt you just have a bad temp sensor. Get it checked
out soon, or you'll end up losing the engine.
10-6-11
have you ever changed the fuel filter near the fuel tank ???
10-12-11
i have a 2000 Alero and i re did the heads and put it all back together but it wont idle
replaced the IAC
10-13-11
i have a 2004 grand am gt 3400 v6 and it wont start. The security light isn't on but its not
getting any spark and i cant hear the fuel pump.  Fuses and the ignition module isn't
getting juice along with others. Replaced fuse same result.
You should re-check all your connections, and make
sure all vacuum lines are connected and routed properly.
If it idled fine before you did the heads, it has to be
something you did in the reassembly process. If it seems
like it running rough, you may have switched push rod
positions by accident, that will cause the car to die out or
run rough. If the check engine light is on, get the code
scanned to see what might be causing the trouble.
10-26-11
Regarding the 2004 3400 problem:
You should make Sure you've properly seated your computer connector(s). Even if you
didn't mess with it, re-seat every major multi-connectors you can find.  Either that or
someone cut through a whole Bundle of wires(or maybe just 1 important one :)   It Could
be Security related.  As these systems(ignition, Fuel pump) are often both linked up with
security system which may cause the problem even IF the light isn't on.  You Could check
the physical integrity of your wires. There's so many though, so just focus on your ICM or
something that makes sense like that.  You just need a multi-meter and then set it to the
beep for connection setting.    - Otherwise, It'd be time for some Professional help to track
down the problem; especially if it's Security system.   That's my few cents, good luck!  -
Glytch '96
11-1-11
I have a 2001
Olds Alero, 3.4L. I have been having problems with the Temperature gauge
working when it wants to. At time it will work fine, other times it will completely drop out and
the electric fans will kick on. It will eventually come back on, on it's own. I've checked the
fuses, they where good.. I've replaced the Temp sensor and it's had the same issue. I've
ohmmed out the harness and it is good. The wires are not frayed or broken. I have no
clue at what else to look at.. Any suggestions???  You think it could be the gauge it's self?
Probably not a problem in the dash gauges, since the
fans come on. The dash does not control the fans, the
gauge shows what the computer thinks the temperature
is. Either a wiring problem or bad computer.
11-19-11
I replaced the timing chain on a 3.1L 3100 V6 engine in a 1997 Oldsmobile Cutlass
Supreme. Does anyone know if this would somehow affect whether or not my oil pump
runs?
No, it would not effect the oil pump at all.
12-1-11
1994 LEXIS WILL CRANK OVER HALF THE TIME. ACTS LIKE DEAD
BATTERY. CHECK VOLTAGE PUSHING OVER 13V POSSIBLE
PROBLEM. WHERE TO LOOK???OR WHAT TO LOOK FOR??? 3000 V 6
24V MOTOR
12-4-11
My 2004 3.4L has a starting issue when the engine is warm. It starts fine
when the engine is cold. I can barely step on the gas pedal when it is warm
and it will start right up. I have cleaned around the throttle body butterfly
and this did no help. Any ideas what may be causing this? I did also see
when cleaning the butterfly that there is a opening just past the butterfly
about the size of a dime that goes down had some carbon build up coming
out of it. I cleaned it out what I could but did not help.
That opening is the idle air passage for the control valve
(IAC). Sounds like you have an idle valve that is not
working. You could try to remove it and clean it real good.
12-6-11
I have a 2000
Chevy Impala 3.8 and my heat get hot when riding in my neighbor but only
blow out warm air when riding on the highway.  What can I do to make my heater blow hot
air at all time.
First check the coolant level. If it is OK, you could have
one of several problems- A sticking thermostat, plugged
heater core, temperature door actuator motor in the
dash, etc. Any one could be faulty.
12-10-11
How do you relieve the fuel pressure in a 2001
Grand Am with the 3400 V6?
12-12-11
I have a 2000 Alero v6. I need to change manifold gaskets. Work time is how long. And
how many gaskets will need to be done to get it to. And where are they all at.
12-14-11
i need some help... I've got a 94 Grand-Am with a 3100 motor and a 4T60e trans. When I
got the car every not and then it starts at high idle about 2,500 rpm.. And it never would
go n low gear or od  then the trans went out and i put a new 4T60e trans in and it still
doing the same thing. I've put a new ECU in and still no change with the shifting.  I'm going
2 run a vacuum pressure test on it and c if that could b it prob. On takeoff it like its n 3rd
gear  and will shift to 2nd if i shift it out by hand but still no OD. If any one could help let
me know something please. Parts starting to cost more then i payed for the car ..LOL
12-21-11
Have a 1994
Buick century with a 3.1 recently replaced fuel pump. Won't start yet have 40
psi fuel pressure at the fuel rail. Runs great when starting fluid is sprayed up the intake so
I have spark I have no idea whats wrong and it's driving me up the wall.
12-22-11
I have a 2001
Chevy Impala that has no spark? What cables are you suppose to connect
to the distributor? What else could it be?
Your car does  not have a distributor. Not sure I
understand the question.
Sounds like you are loosing fuel injector pulse. This is
controlled by the PCM. Check all fuses, then check with a
test light that the injectors are getting a signal to fire.
12-27-11
Have a 1995  Chevy Berreta 3.1 running rich can't get the service engine light to go off. I
have replaced plugs,fuel filter,& regulator egr valve,air filter cleaned port in intake
that goes to EGR. Any ideas. Thanks.
12-28-11
My car is a 2001 Buick Century. When car is warmed up it idles high and takes off when
gas pedal isn't pressed. It's burning fuel like crazy. I think my car is possessed or
something.  HELP ME PLEASE. Thank you so very much. Desperate
12-29-11
I have a 1998 Grand Prix SE 3.1L engine.  The car won't pull a hill in the higher gear,
especially when the car is warm.  ( pulls it somewhat better when cold ).  And even on a
flat surface, I just can't take off and throttle as fast I want to.  It's a slow acceleration.
If you are sure it is running rich, the EGR has nothing to
do with it. What codes do you have stored. If it is rich and
the fuel pressure regulator (FPR) did not fix it, then your
car probably has a leaking fuel injector.
Sounds like a possibly low fuel pressure condition or
plugged catalytic converter. Get the computer codes
scanned first. May give a direction to the problem.
1-7-12
I have a 1995 Chevy Monte Carlo Z34 when the outside temp is less than 50 the cold car
revs 5000rpm then dies. This goes on until the car warms up then it runs fine. It runs fine
when the outside temp is over 50. No codes are stored.
1-11-12
I am having problems with a Pontiac Grand Am It is just very difficult to start it sounds like if
it is getting to much fuel, because wen I push the gas half way it start. Although it does it
with difficulty and for the first seconds the engine sounds like it is going to turn of and it
smokes black. Then it starts to function very normal and acceleration is good. Does any
body has any idea what can cause this issue?
Sounds like a leaking fuel pressure regulator causing a
rich condition. Just pull the vacuum hose off of it after it
has been off for a few minutes and look for gas to come
out of it.
1-15-12
I have a 2001 Buick Century press on gas loud whistling no power after half throttle noise
goes away can not get overt 30 mph could it be converter.
1-18-12
2003 Buick Century that quits when its warmed up, but not always.  Replaced the fuel
pump, fuel filter, and coil assembly...nothing is working?
1-20-12
2003 Alero 3400.  Rough idle, runs fine otherwise.  Gas smell in passenger compartment
while driving.  EGR issue?  Fuel injector issue?
1-20-12
Alright. Ive had a 2000 Alero v6 3.4L. Ive had some good battles with it, but it seems to
always win. I've just eliminated the leaks that the car once had by replacing the lower
intake gasket. I then pressurized the system, ran the air out etc. It had been running fine,
idle it had heat in the cab, but driving around the city the heat comes and goes in bursts.
Taking the car on the highway the temperature gauge has hit the roof, sprayed out some
coolant out of the overflow, but when I released some of the pressure via rad cap it drove
fine on the highway, steady heat (minus in the cab, as it still comes and goes) I keep
feeding it coolant but it does not want to keep it even though the cold level in the res is at
the bottom when I checked the car cold. The thermostat has been changed twice in the
last month, the sensor as well. The fans seem to run but they are running slower and
quieter then I remember, the oil is clean, and there is no sign of coolant in it. Also notable
the upper rad hose had blown and was replaced, and I know the thermostat isn't faulty
because when  the car reached operating temp the upper rad hose compressed and I
assume that means the block sucked it in. I'm at a loss with it.
The noise you are hearing is the exhaust trying to
escape but cannot because your car has a plugged
catalytic converter.
1-26-11
I have a 1995
Chevy Monte Carlo Z34 when the outside temp is less than 50 the cold car
revs 5000rpm then dies. This goes on until the car warms up then it runs fine. It runs fine
when the outside temp is over 50. No codes are stored. I have the exact same car and the
exact same problem, I have cleaned the throttle body, fuel injectors and MAF Sensor,
changed a broken intake manifold gasket, replaced the IAC, PCV, and EGR valves, and it
STILL does it.  Next thing I'm going to look at, and probably should have looked at sooner
is the Intake Air Temperature sensor.
Most likely a leaking fuel pressure regulator (FPR) or a
stuck open fuel injector causing a rich condition and
smell of gas in the car.
Simple, you have a blown headgasket. Most common is
the rear.
1-30-12
I checked the Intake Air Temp sensor, and it was fine, if it's not the Engine Coolant Temp
sensor... I give up!
1-30-12
2000 Pontiac Aztec 3400 leaks coolant when the motor is warm back behind the back
head up by the valve cover behind the alternator there is no coolant in the oil but dont
leak when the car is cold and haven't been running cant find or see what would be
causing this problem
2-2-12
Where are the O2 sensors Located on a V6, 3.4L 2002 Alero.
If you have the 3400 dual overhead cam engine (DOHC)
then you have a lower intake leaking vacuum.
The rear head gasket is leaking. You should probably do
both since it most likely has over heated.
One is in the rear exhaust manifold, the other is after the
catalytic converter.
2-5-12
2003 Alero will crank, but not start when temp is below 50 and cold outside. Replace crank
sensor,fuel pump checked fuel injectors,after a few attempts to start,security light is on,
will leave it alone for awhile,starts right up. Will do the same thing every cold morning.
2-5-12
2001 Pontiac Aztek overheats, lots of coolant. Changed water pump, fine for a week,
various other things(too many that I've forgotten but my mechanic certainly knows) next on
list is the sensor, is this a possible gasket problem or just a sensor issue?
More Comments>>
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3.4L and 3.1L V6 Engine Sensor Locations

Add yours below.
2tone said:
Rough idle stalling on warm start found that my pcv valve was bad not breathing like it should causing it to stall when it idled down.

Anonymous said:
I have a 95 Chevy Lumina 3.4 dohc when you first start it in the morning it will rev to bout 3500-4500rpm then bk down n almost die and sometimes
does die. I've replaced everything I know to and no luck wen idling it will overheat should both fans kick on or just one of them? Please help.

Tom said:
Reply to annonymous: your 3.4 L DOHC has the common problem of the intake manifold gaskets leaking vacuum.

1. Fuel pressure regulator       2. Idle Air Control Motor (IAC)         3. Mass Airflow sensor (MAF)
4. Throttle Body                       5. Throttle Position Sensor (TPS)   6. Fuel Injector
7. PCV Valve                           8. Coolant Temp sensor (ECT)       9. Evap Purge Solenoid