YJ computer question
Guest
Posts: n/a
Re: YJ computer question
nrs wrote:
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
Can't say for the 95, but the on the 93 if it fails to get sensor input
from the CPS, the ignition shuts down (ASD) after about two cranks.
I've started the engine without the coolant, O2, and MAT sensors.
Haven't tried disconnecting the MAP though, but it should run at
least in limp-home mode.
The last time I had a problem with nostart it was due to a coil
going bad. One of the issues (if you have a return style fuel
rail) is the pressure regulator leaking. This makes the jeep take
more time to pressurize the rail and is usually the cause. Easy
way to tell is to turn the key on (let the pump buzz) then turn
the key off, then start the engine. That primes the rail.
In some real bad cases air can get into the rail and make for
a real interesting start. (think bucking horse)
--
DougW
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
Can't say for the 95, but the on the 93 if it fails to get sensor input
from the CPS, the ignition shuts down (ASD) after about two cranks.
I've started the engine without the coolant, O2, and MAT sensors.
Haven't tried disconnecting the MAP though, but it should run at
least in limp-home mode.
The last time I had a problem with nostart it was due to a coil
going bad. One of the issues (if you have a return style fuel
rail) is the pressure regulator leaking. This makes the jeep take
more time to pressurize the rail and is usually the cause. Easy
way to tell is to turn the key on (let the pump buzz) then turn
the key off, then start the engine. That primes the rail.
In some real bad cases air can get into the rail and make for
a real interesting start. (think bucking horse)
--
DougW
Guest
Posts: n/a
Re: YJ computer question
On Oct 1, 4:35 pm, "DougW" <I.only.read.use...@invalid.address> wrote:
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
Guest
Posts: n/a
Re: YJ computer question
On Oct 1, 4:35 pm, "DougW" <I.only.read.use...@invalid.address> wrote:
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
Guest
Posts: n/a
Re: YJ computer question
On Oct 1, 4:35 pm, "DougW" <I.only.read.use...@invalid.address> wrote:
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
Guest
Posts: n/a
Re: YJ computer question
On Oct 1, 4:35 pm, "DougW" <I.only.read.use...@invalid.address> wrote:
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
> nrs wrote:
> > Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> > before providing ground for turning on the check engine light, ASD
> > relay and fuel pump relay?
>
> Can't say for the 95, but the on the 93 if it fails to get sensor input
> from the CPS, the ignition shuts down (ASD) after about two cranks.
>
> I've started the engine without the coolant, O2, and MAT sensors.
> Haven't tried disconnecting the MAP though, but it should run at
> least in limp-home mode.
>
> The last time I had a problem with nostart it was due to a coil
> going bad. One of the issues (if you have a return style fuel
> rail) is the pressure regulator leaking. This makes the jeep take
> more time to pressurize the rail and is usually the cause. Easy
> way to tell is to turn the key on (let the pump buzz) then turn
> the key off, then start the engine. That primes the rail.
> In some real bad cases air can get into the rail and make for
> a real interesting start. (think bucking horse)
>
> --
> DougW
Wow, so it can run with some sensors disabled. This makes it even
less likely that it is a sensor problem. I'm thinking PCM much more
seriously now. The problem I'm having is that whan I turn the key to
run to let the pump buzz (this also usually lights the check engine
light at the same time) it does nothing for a while (16 seconds this
morning), then it suddenly comes on and I am able to start the jeep.
If I don't confirm that the pump has run, it just won't start when
cranking (well, maybe it would if I let it crank for 16 seconds!)
Guest
Posts: n/a
Re: YJ computer question
On 1 oct, 09:33, nrs <neale...@yahoo.com> wrote:
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
Guest
Posts: n/a
Re: YJ computer question
On 1 oct, 09:33, nrs <neale...@yahoo.com> wrote:
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
Guest
Posts: n/a
Re: YJ computer question
On 1 oct, 09:33, nrs <neale...@yahoo.com> wrote:
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
Guest
Posts: n/a
Re: YJ computer question
On 1 oct, 09:33, nrs <neale...@yahoo.com> wrote:
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
> before providing ground for turning on the check engine light, ASD
> relay and fuel pump relay?
>
> Thanks
Just in case it is the PCM and I decide to get a used one, how can I
make sure I'm getting the right one for my YJ?
Guest
Posts: n/a
Re: YJ computer question
get one out of another YJ?
nrs wrote:
>> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
>> before providing ground for turning on the check engine light, ASD
>> relay and fuel pump relay?
>>
>> Thanks
>
>Just in case it is the PCM and I decide to get a used one, how can I
>make sure I'm getting the right one for my YJ?
--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200710/1
nrs wrote:
>> Does anyone know if the ´95 YJ PCM waits for a signal from any sensor
>> before providing ground for turning on the check engine light, ASD
>> relay and fuel pump relay?
>>
>> Thanks
>
>Just in case it is the PCM and I decide to get a used one, how can I
>make sure I'm getting the right one for my YJ?
--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200710/1