93 Altima stalling at random

"AMuzi" > wrote in message
...
> Heron wrote:
>> "jim beam" > wrote in message
>> ...
>>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>>> mark wrote:
>>>>> Engine stalls after 5-10 minutes just idling and won't start again for
>>>>> a few hours. Distributor was changed last year and I cannot see any
>>>>> oil leakage into the sensor area. Since changing the oil which was
>>>>> very dirty. it has not stalled but I can't believe that caused the
>>>>> problem. I just don't trust it.
>>>>>
>>>>> Any ideas?
>>>> Check the oil pressure sender. If it is failing it can do this by
>>>> shutting the fuel pump off.
>>> now /that/ is exactly the kind of knowledge/experience that makes this
>>> forum excellent.
>>
>> The pressure/volume being adequate obviates
>> the need for checking the oil presure sender.
> If the sender itself is damaged or has a frayed wire or connector
> (intermittent signal), wouldn't that cause his symptom regardless of the
> correct amount of clean pressurized oil available?

I'm not sure as to your meaning, but I thought it obvious
from my earlier post that I was referencing FUEL supply.

Heron wrote:
> "jim beam" > wrote in message
> ...
>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>> mark wrote:
>>>> Engine stalls after 5-10 minutes just idling and won't start again for
>>>> a few hours. Distributor was changed last year and I cannot see any
>>>> oil leakage into the sensor area. Since changing the oil which was
>>>> very dirty. it has not stalled but I can't believe that caused the
>>>> problem. I just don't trust it.
>>>>
>>>> Any ideas?
>>> Check the oil pressure sender. If it is failing it can do this by
>>> shutting the fuel pump off.
>> now /that/ is exactly the kind of knowledge/experience that makes this
>> forum excellent.
>
> The pressure/volume being adequate obviates
> the need for checking the oil presure sender.
>
>

Nope. Just means that the pump is OK. The sender being bad allows the
pump to run until the engine warms up a bit and the oil thins out fully.
Then the switch shuts off the pump and the engine sputters to a stop on
the residual pressure in the system. Once the engine cools down again
the oil creates just enough pressure that the switch turns the pump on
and it starts the cycle over.

The usual switch failure is due to the diaphragm in the switch failing
and the oil manages to get into the mechanical side of the switch. This
equalizes the pressure on both sides of the switch actuator and the
switch responds to very small pressure changes. Instead of on/off at
8-10 PSI they will toggle with 1/2 - 1 pound of pressure.

--
Steve W.

"Steve W." > wrote in message
...
> Heron wrote:
>> "jim beam" > wrote in message
>> ...
>>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>>> mark wrote:
>>>>> Engine stalls after 5-10 minutes just idling and won't start again for
>>>>> a few hours. Distributor was changed last year and I cannot see any
>>>>> oil leakage into the sensor area. Since changing the oil which was
>>>>> very dirty. it has not stalled but I can't believe that caused the
>>>>> problem. I just don't trust it.
>>>>>
>>>>> Any ideas?
>>>> Check the oil pressure sender. If it is failing it can do this by
>>>> shutting the fuel pump off.
>>> now /that/ is exactly the kind of knowledge/experience that makes this
>>> forum excellent.
>>
>> The pressure/volume being adequate obviates
>> the need for checking the oil presure sender.
>
> Nope. Just means that the pump is OK. The sender being bad allows the pump
> to run until the engine warms up a bit and the oil thins out fully. Then
> the switch shuts off the pump and the engine sputters to a stop on the
> residual pressure in the system. Once the engine cools down again the oil
> creates just enough pressure that the switch turns the pump on and it
> starts the cycle over.
>
> The usual switch failure is due to the diaphragm in the switch failing and
> the oil manages to get into the mechanical side of the switch. This
> equalizes the pressure on both sides of the switch actuator and the switch
> responds to very small pressure changes. Instead of on/off at 8-10 PSI
> they will toggle with 1/2 - 1 pound of pressure.
>
> --
> Steve W.

Sorry but if there's adequate pressure/volume (with the engine
running, of course), the pump is not only OK, it is energized,
which obviates the need for checking the oil pressure sender.
Perhaps you didn't notice my usage of the term adequate.
The scenario you describe temporarily disables the pump
and inarguably decreases the system pressure and volume.

Heron wrote:
> "Steve W." > wrote in message
> ...
>> Heron wrote:
>>> "jim beam" > wrote in message
>>> ...
>>>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>>>> mark wrote:
>>>>>> Engine stalls after 5-10 minutes just idling and won't start again for
>>>>>> a few hours. Distributor was changed last year and I cannot see any
>>>>>> oil leakage into the sensor area. Since changing the oil which was
>>>>>> very dirty. it has not stalled but I can't believe that caused the
>>>>>> problem. I just don't trust it.
>>>>>>
>>>>>> Any ideas?
>>>>> Check the oil pressure sender. If it is failing it can do this by
>>>>> shutting the fuel pump off.
>>>> now /that/ is exactly the kind of knowledge/experience that makes this
>>>> forum excellent.
>>> The pressure/volume being adequate obviates
>>> the need for checking the oil presure sender.
>> Nope. Just means that the pump is OK. The sender being bad allows the pump
>> to run until the engine warms up a bit and the oil thins out fully. Then
>> the switch shuts off the pump and the engine sputters to a stop on the
>> residual pressure in the system. Once the engine cools down again the oil
>> creates just enough pressure that the switch turns the pump on and it
>> starts the cycle over.
>>
>> The usual switch failure is due to the diaphragm in the switch failing and
>> the oil manages to get into the mechanical side of the switch. This
>> equalizes the pressure on both sides of the switch actuator and the switch
>> responds to very small pressure changes. Instead of on/off at 8-10 PSI
>> they will toggle with 1/2 - 1 pound of pressure.
>>
>> --
>> Steve W.
>
> Sorry but if there's adequate pressure/volume (with the engine
> running, of course), the pump is not only OK, it is energized,
> which obviates the need for checking the oil pressure sender.
> Perhaps you didn't notice my usage of the term adequate.
> The scenario you describe temporarily disables the pump
> and inarguably decreases the system pressure and volume.
>
>

The switch does NOT "temporarily disable" the fuel pump it will shut it
off until the oil pressure is restored. Just like it is supposed to do
if the oil pressure drops. The pump will stay off until you try to
restart the engine. At that time the FP Relay kicks on, pressurizes the
system and you start the engine. The relay only stays on for a few
seconds. Once the oil pressure rises (which it should do almost
instantly) and crosses the switches threshold it turns on and sends
power to the fuel pump, either directly or by telling the ECM that there
is oil pressure and turning the relay back on.

In the OPs case the pump turns on for the initial prime. The engine
starts and the cold oil trips the switch. Once the oil heats up and
thins out some the O/P sender trips off thinking the engine has no oil
pressure. That in turn shuts the pump off. The engine the "acts like it
is vapor locked" because the pump is now off.

Testing the fuel pump will show absolutely nothing if it's the switch.
The proper testing procedure bypasses all the controls on the pump and
only tests the pump. Low pressure or volume will not show this symptom.
The engine will run fine until the fuel requirement exceeds the ability
of the pump to supply fuel, then it will lose power. The common item you
see with this is a vehicle that starts and runs fine, until you go over
a certain engine % of load, then it falls off until it drops below that
load %. The common complaint from the owner is " Well it runs ok but you
can't go over XX mph" The same symptoms you get with a partly plugged
fuel filter, and for the same reason, low fuel flow.

The clincher to the problem is the stated " Since changing the oil,
which was very dirty. It has not stalled" The fresh clean oil can only
effect ONE item that has anything to do with the fuel. That would be the
oil pressure sending unit.


--
Steve W.

"Steve W." > wrote in message
...
> Heron wrote:
>> "Steve W." > wrote in message
>> ...
>>> Heron wrote:
>>>> "jim beam" > wrote in message
>>>> ...
>>>>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>>>>> mark wrote:
>>>>>>> Engine stalls after 5-10 minutes just idling and won't start again
>>>>>>> for
>>>>>>> a few hours. Distributor was changed last year and I cannot see any
>>>>>>> oil leakage into the sensor area. Since changing the oil which was
>>>>>>> very dirty. it has not stalled but I can't believe that caused the
>>>>>>> problem. I just don't trust it.
>>>>>>>
>>>>>>> Any ideas?
>>>>>> Check the oil pressure sender. If it is failing it can do this by
>>>>>> shutting the fuel pump off.
>>>>> now /that/ is exactly the kind of knowledge/experience that makes this
>>>>> forum excellent.
>>>> The pressure/volume being adequate obviates
>>>> the need for checking the oil presure sender.
>>> Nope. Just means that the pump is OK. The sender being bad allows the
>>> pump
>>> to run until the engine warms up a bit and the oil thins out fully. Then
>>> the switch shuts off the pump and the engine sputters to a stop on the
>>> residual pressure in the system. Once the engine cools down again the
>>> oil
>>> creates just enough pressure that the switch turns the pump on and it
>>> starts the cycle over.
>>>
>>> The usual switch failure is due to the diaphragm in the switch failing
>>> and
>>> the oil manages to get into the mechanical side of the switch. This
>>> equalizes the pressure on both sides of the switch actuator and the
>>> switch
>>> responds to very small pressure changes. Instead of on/off at 8-10 PSI
>>> they will toggle with 1/2 - 1 pound of pressure.
>>>
>>> --
>>> Steve W.
>>
>> Sorry but if there's adequate pressure/volume (with the engine
>> running, of course), the pump is not only OK, it is energized,
>> which obviates the need for checking the oil pressure sender.
>> Perhaps you didn't notice my usage of the term adequate.
>> The scenario you describe temporarily disables the pump
>> and inarguably decreases the system pressure and volume.
>
> The switch does NOT "temporarily disable" the fuel pump it will shut it
> off until the oil pressure is restored.

Of course it's "temporarily disabled" by a lack of electrical
power does, your statement is an attempted obfuscation
and a semantics difference without distinction.

> Just like it is supposed to do if the oil pressure drops. The pump will
> stay off until you try to restart the engine.

If that doesn't fit the definiton of disabled, I don't know what could.

> At that time the FP Relay kicks on, pressurizes the system and you start
> the engine. The relay only stays on for a few seconds. Once the oil
> pressure rises (which it should do almost instantly) and crosses the
> switches threshold it turns on and sends power to the fuel pump, either
> directly or by telling the ECM that there is oil pressure and turning the
> relay back on.
>
> In the OPs case the pump turns on for the initial prime. The engine starts
> and the cold oil trips the switch. Once the oil heats up and thins out
> some the O/P sender trips off thinking the engine has no oil pressure.
> That in turn shuts the pump off. The engine the "acts like it is vapor
> locked" because the pump is now off.
>
> Testing the fuel pump will show absolutely nothing if it's the switch.

No, testing the fuel delivery system at the fuel rail, not
simply a bench test of the fuel pump, will clearly indicate
a lack of adequate pressure.

> The proper testing procedure bypasses all the controls on the pump and
> only tests the pump. Low pressure or volume will not show this symptom.

Sorry, but still not true irrespective of the number
of times you choose to reiterate the same nonsense.

> The engine will run fine until the fuel requirement exceeds the ability of
> the pump to supply fuel, then it will lose power. The common item you see
> with this is a vehicle that starts and runs fine, until you go over a
> certain engine % of load, then it falls off until it drops below that load
> %. The common complaint from the owner is " Well it runs ok but you can't
> go over XX mph" The same symptoms you get with a partly plugged fuel
> filter, and for the same reason, low fuel flow.

Not the same at all, the latter is a restriction but in both
cases they result in and can be diagnosed as a non
adequate delivery of pressure or volume at the fuel rail.

> The clincher to the problem is the stated " Since changing the oil, which
> was very dirty. It has not stalled" The fresh clean oil can only effect
> ONE item that has anything to do with the fuel. That would be the oil
> pressure sending unit.

Sans any data acquisition whatsoever, that's a guess and no
difinitive diagnosis exists. It is still POSSIBLY a failing fuel
pump.

Cat was replaced a yr ago as was the fuel pump.

Will chk codes and spark if it stalls again.

Anyone know where the oil pressure sending unit is? - no mention of it in
the Hayes manual.

"mark" > wrote in message
...
> Cat was replaced a yr ago as was the fuel pump.
>
> Will chk codes and spark if it stalls again.
>
> Anyone know where the oil pressure sending unit is? - no mention of it in
> the Hayes manual.

You might indicate the engine type, but a common
location is in the near vicinity of the oil filter.

mark wrote:
> Cat was replaced a yr ago as was the fuel pump.
>
> Will chk codes and spark if it stalls again.
>
> Anyone know where the oil pressure sending unit is? - no mention of it in
> the Hayes manual.


Under the vehicle to the right of the oil filter just above the axle shaft.

--
Steve W.

On 06/15/2012 04:36 PM, Heron wrote:
> "Steve > wrote in message
> ...
>> Heron wrote:
>>> "Steve > wrote in message
>>> ...
>>>> Heron wrote:
>>>>> "jim > wrote in message
>>>>> ...
>>>>>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>>>>>> mark wrote:
>>>>>>>> Engine stalls after 5-10 minutes just idling and won't start again
>>>>>>>> for
>>>>>>>> a few hours. Distributor was changed last year and I cannot see any
>>>>>>>> oil leakage into the sensor area. Since changing the oil which was
>>>>>>>> very dirty. it has not stalled but I can't believe that caused the
>>>>>>>> problem. I just don't trust it.
>>>>>>>>
>>>>>>>> Any ideas?
>>>>>>> Check the oil pressure sender. If it is failing it can do this by
>>>>>>> shutting the fuel pump off.
>>>>>> now /that/ is exactly the kind of knowledge/experience that makes this
>>>>>> forum excellent.
>>>>> The pressure/volume being adequate obviates
>>>>> the need for checking the oil presure sender.
>>>> Nope. Just means that the pump is OK. The sender being bad allows the
>>>> pump
>>>> to run until the engine warms up a bit and the oil thins out fully. Then
>>>> the switch shuts off the pump and the engine sputters to a stop on the
>>>> residual pressure in the system. Once the engine cools down again the
>>>> oil
>>>> creates just enough pressure that the switch turns the pump on and it
>>>> starts the cycle over.
>>>>
>>>> The usual switch failure is due to the diaphragm in the switch failing
>>>> and
>>>> the oil manages to get into the mechanical side of the switch. This
>>>> equalizes the pressure on both sides of the switch actuator and the
>>>> switch
>>>> responds to very small pressure changes. Instead of on/off at 8-10 PSI
>>>> they will toggle with 1/2 - 1 pound of pressure.
>>>>
>>>> --
>>>> Steve W.
>>>
>>> Sorry but if there's adequate pressure/volume (with the engine
>>> running, of course), the pump is not only OK, it is energized,
>>> which obviates the need for checking the oil pressure sender.
>>> Perhaps you didn't notice my usage of the term adequate.
>>> The scenario you describe temporarily disables the pump
>>> and inarguably decreases the system pressure and volume.
>>
>> The switch does NOT "temporarily disable" the fuel pump it will shut it
>> off until the oil pressure is restored.
>
> Of course it's "temporarily disabled" by a lack of electrical
> power does, your statement is an attempted obfuscation
> and a semantics difference without distinction.
>
>> Just like it is supposed to do if the oil pressure drops. The pump will
>> stay off until you try to restart the engine.
>
> If that doesn't fit the definiton of disabled, I don't know what could.
>
>> At that time the FP Relay kicks on, pressurizes the system and you start
>> the engine. The relay only stays on for a few seconds. Once the oil
>> pressure rises (which it should do almost instantly) and crosses the
>> switches threshold it turns on and sends power to the fuel pump, either
>> directly or by telling the ECM that there is oil pressure and turning the
>> relay back on.
>>
>> In the OPs case the pump turns on for the initial prime. The engine starts
>> and the cold oil trips the switch. Once the oil heats up and thins out
>> some the O/P sender trips off thinking the engine has no oil pressure.
>> That in turn shuts the pump off. The engine the "acts like it is vapor
>> locked" because the pump is now off.
>>
>> Testing the fuel pump will show absolutely nothing if it's the switch.
>
> No, testing the fuel delivery system at the fuel rail, not
> simply a bench test of the fuel pump, will clearly indicate
> a lack of adequate pressure.
>
>> The proper testing procedure bypasses all the controls on the pump and
>> only tests the pump. Low pressure or volume will not show this symptom.
>
> Sorry, but still not true irrespective of the number
> of times you choose to reiterate the same nonsense.
>
>> The engine will run fine until the fuel requirement exceeds the ability of
>> the pump to supply fuel, then it will lose power. The common item you see
>> with this is a vehicle that starts and runs fine, until you go over a
>> certain engine % of load, then it falls off until it drops below that load
>> %. The common complaint from the owner is " Well it runs ok but you can't
>> go over XX mph" The same symptoms you get with a partly plugged fuel
>> filter, and for the same reason, low fuel flow.
>
> Not the same at all, the latter is a restriction but in both
> cases they result in and can be diagnosed as a non
> adequate delivery of pressure or volume at the fuel rail.
>
>> The clincher to the problem is the stated " Since changing the oil, which
>> was very dirty. It has not stalled" The fresh clean oil can only effect
>> ONE item that has anything to do with the fuel. That would be the oil
>> pressure sending unit.
>
> Sans any data acquisition whatsoever, that's a guess and no
> difinitive diagnosis exists. It is still POSSIBLY a failing fuel
> pump.
>
>

i think you're being more than a little harsh. if, as steve indicates,
and he's usually pretty reliable, the engine computer has a "fail safe"
shutting down the engine on low oil pressure, then everything he says
makes sense. if of course the engine doesn't have this fail safe mode,
and many older vehicles do not, then your conclusion about the pump
could be one that fits.

so, given that there's a question about the input control logic on this
vehicle that needs to be understood before jumping to conclusions on its
output, why not go check up on the fail safe functionality of this oil
pressure switch, then let us know what you find?


--
fact check required

On 06/15/2012 10:01 AM, Heron wrote:
> > wrote in message
> ...
>> Heron wrote:
>>> "jim > wrote in message
>>> ...
>>>> On 06/15/2012 07:17 AM, Steve W. wrote:
>>>>> mark wrote:
>>>>>> Engine stalls after 5-10 minutes just idling and won't start again for
>>>>>> a few hours. Distributor was changed last year and I cannot see any
>>>>>> oil leakage into the sensor area. Since changing the oil which was
>>>>>> very dirty. it has not stalled but I can't believe that caused the
>>>>>> problem. I just don't trust it.
>>>>>>
>>>>>> Any ideas?
>>>>> Check the oil pressure sender. If it is failing it can do this by
>>>>> shutting the fuel pump off.
>>>> now /that/ is exactly the kind of knowledge/experience that makes this
>>>> forum excellent.
>>>
>>> The pressure/volume being adequate obviates
>>> the need for checking the oil presure sender.
>> If the sender itself is damaged or has a frayed wire or connector
>> (intermittent signal), wouldn't that cause his symptom regardless of the
>> correct amount of clean pressurized oil available?
>
> I'm not sure as to your meaning, but I thought it obvious
> from my earlier post that I was referencing FUEL supply.

but if the fuel is being switched by the ecu, and they usually are, then
his point is perfectly valid.


--
fact check required