Engine stalls, fuel line problem?

Hi

I have a Saturn SL1 1995 4 cyl SOHC, manual transmission, mileage >
142,000Km.

I have recently had 3 incidences of stalls where the engine light turns on
and the car seemed starved of fuel. I had the fuel filter changed
recently at about 138,000Km, and the fuel pump works fine when I hear it
prime the fuel line.

This morning the engine stalled again. When I tried restarting, I had to
rev the engine to about 3000rpm to get it restarted. It still seems to be
a fuel pressure problem. The air filter is fine (fairly new) and the oil
has just been changed (5W30), although it seems that the service-man
overfilled the oil by maybe 1/2 Litre. The spark plugs were changed last
autumn and the plug wires passed testing.

I'm thinking that there may be a problem with the O2 sensor. Does anyone
have suggestions?

Thanks, Roger

 

Roger,

Could you provide more insight beyond just "stalling"?

When does the stalling occur? Was it during idling in park/at a stop sign
when at very low RPM or was it when you were cruising the highway at 60+MPH?
Any problems previously noted during attempted acceleration when at high a
rate of speed? (If it was a fuel filter or fuel pump they tend to exhibit
signs of failure when delivering the maximum gas flow.) How does the
vehicle idle? (A dirty throttle body would cause poor idling and could
result in the vehicle stalling at very low RPM.)

Bob

PS How do you rev a "stalled" engine to 3,000RPM?

 

Hi Bob
Thanks for your response, much appreciateed.

The engine stalls at near idle (occurred a traffic light). The engine was
warm, running for 30 min. However I noticed some signs of the stall
coming before I came to a full stop. The rpm was under 2000. I was
traveling at 70Km/hr (45mil/hr), rpm 2000-2400, then braking and gearing
down as I approached the stop light. There does not seem to be a problem
at high rpm/acceleration. I cleaned the throttle body last summer and have
checked it since, it looks good (no deposits).

 

Roger,

You did not say if the vehicle idles smoothly or not. But if the throttle
body is clean and the plugs and wires are also good, then I'd look at the
fuel injectors and the air intake servo (AIS) in that order. (I'm assuming
from the failure when you were gearing down and then stalling at idle that
it probably is not idling smoothly and/or idle RPM is a bit low.)

You could try throwing in a bottle of some good fuel injector cleaner first
(I like Chevron Techron) to see if this helps any. If this does nothing,
then you might take another look at the throttle body and AIS to make sure
EVERYTHING (not just the throttle plate and body where it contacts) is
really clean and that the servo is operating properly. I'm not familiar
enough with the Saturn AIS to give you any specific instructions on how to
test it or if it is a common point of failure, but suspect others in this
newsgroup will have more specific experience for you.

Bob

 

Could also be a stuck EGR, a stuck TCC, or something odd thing. I had
diagnosed a ford that had a locked up AC compressor and it would stall
the engine when you braked.

 

Is this automatic? Does it do this the most at the end of highway exit
ramps or right after you've been driving at semi high - high speeds for
a few min? If you answered 'yes' to both of these - does the car jerk
and shudder right before it stalls? If so, have someone look at the
torque converter clutch. It can cause weird stalling, and you'd swear
it's an engine problem until you stumble on this.

 

I solved a stalling problem by removing the EGR valve and cleaning
it really well, using a tubular wire brush and solvent.
Even though the pintle seemed to move freely up and down,
the carbon deposits apparently were sufficient to cause low-RPM stalling.

Pigeon

 

Thanks Bob, Philip and all aliases for your helpful advice.

The transmission is manual not automatic. It does exhibit almost exactly
the symptoms Philip described....

"Is this automatic? Does it do this the most at the end of highway exit
ramps or right after you've been driving at semi high - high speeds for
a few min? If you answered 'yes' to both of these - does the car jerk
and shudder right before it stalls? If so, have someone look at the
torque converter clutch. It can cause weird stalling, and you'd swear
it's an engine problem until you stumble on this."

......Bob: Typical idling for my car's engine is around 700 rpm when warm,
(1000-1200 when cold). The idling was not smooth when these incidences
occurred, and idling was near 700. I will check the throttle body again,
and will add fuel injector cleaner, (I have a bottle of STP Concentrated
FI cleaner, I never came across the Chevron Techron brand up here in
Canada: Canadian Tire or Walmart).

I'll also check the AIS. I will not have a TCC (torque converter clutch)
my car has a manual trans. During this last episode, I restarted my car
after letting it rest for 9 hours (parked @ work). It began to stall
during restart (700-1000 rpm). With the car in neutral I pressed the
accelerator up to 3500-3800 rpm. The engine "sputtered" for a bit but then
ran without stalling. This action seemed to clear the fuel line. I drove
the car in the parking lot to test it, and I noticed that the throttle
was high when depressing the clutch to shift gears up to 3rd. ie: the rpm
would actually rise above the running rpm (2000) to about 2800-3000
and race while shifting.
I recall that this happened before, during an incident when I ran
out of gas and restarted the car after re-fueling. As I did then, I
turned off the ignition waited for a minute then restarted the engine and
it ran fine. Maybe someone can confirm if fuel line problems upsets the
computer calibration of the fuel injection system and may require a
couple of restarts to re-establish normal operation.

My gas tank was just over 1/8 full, I drove to a gas station and refueled
with 91 octane petrol, (normally I use 87 octane). The car has been
running fine since. I also visited the Service dept at a local Saturn
dealer, although they did not have an available appointment for me to
connect the diagnostic computer, the service agent did speak to me as to
the possible causes of this problem.
Knowing I had a new fuel filter in place, he too suggested the EGR valve
and possibly the throttle body and O2 sensor. He also suggested that I may
have come across some bad petrol during my last fuel up. That ideally
people should refuel when the gas stations receive a new supply of fuel
and not get the "cruddy gas near the bottom of their supply tanks". There
may also have been some water in my fuel system. What do others feel about
this?

I also added a bottle (400ml) of Wynn's MetalOil to the crankcase,and the
engine runs smoother. Any suggestions by others as to the use of these
engine treatment products is welcome.

Cheers, Roger

 

Remove the throttle body when you do this (get a new gasket first
It's two torx screws to pull out. You can clean the TB really well
after you remove the TPS and IAC valves. And they go on/off real easy,
it's obvious how they fit in place. The bolts are 10mm, by the way.
Use a 3" extension, 1/4" drive gets in there better than larger ones.

Ok, two things:

* Dissconnect the negative from the battery, let the car sit a few
hours, and reconnect it. Make sure both the positive and negatives are
tight. Maybe the computer's been having a bad day? I wonder too if
voltage problems could cause this?

* Coolant temp sensor, and if your car has it, temp sender. Some
Saturns have both - one just works the gauge, the other tells the
computer what to do. I knew a kid who had the exact same problem, that
was it. Check / replace yours - sometimes even the replacements are
bad...

If it's happening when the car's cold, it's NOT the O2 sensor. The O2
sensor is not active when the car is started. IIRC, it's only active
once the car's warmed up and a certain time has passed.

 

If I missed this already being suggested, ignore me. This is a long
shot, but you said you've cleaned and messed with the throttle body.
Any chance the throttle position sensor is hosed and/or malfunctioning?

My 98SL2 had what sounds like the exact opposite problem you describe -
the engine randomly would rev up and then idle around 1800-2200rpms
instead of the normal 700-1100. Turned out the TPS was feeding the PCM
bad data.

-rj
98SL2