some useful? info on testing injectors
 

Talked to the owner of a local shop today (Sooner Auto on AirDepot,
Midwest City, OK). Good shop, I use them to fix my mom's 86 Merc.
Especially when I'm up to my elbows in Jeep or just don't have the
time/equipment.

Asked about a local place that would clean/test injectors off the vehicle
and they weren't aware of one but he did explain an interesting method to
check injectors for proper (mostly proper) operation. You can't check
the spray pattern this way but it might be a good idea if all the other
rough idle solutions arn't working.

Basically you pressurize the fuel rail then watch a pressure gauge
hooked to the rail as you fire off one of the injectors. (The tricky
part is the test gear that fires them for a set time in milliseconds).
Wash, rinse, repeat for all injectors and that gives you the delivery
for each. Compared with the factory spec you now know if they are
delivering the proper amount of fuel. That indicates ones that are
slow to close, plugged, or worn and needs replacing. (or possibly a
good cleaning)

I think one could build such a test rig with some simple RadioShack parts
like a 555 timer and a power transistor. But it would take more time and
money than just having them do it. Mebby if I run across an old injector
to play with.

What I need is a spare set so these can be shipped away, cleaing and testing
is about 1/6 the cost of a new injector.

--
DougW

Re: some useful? info on testing injectors
 

Sounds like a project for my electronic skills.

Can someone give me the low down on how these are triggered?

"DougW" <post.replies@invalid.address> wrote in message
news:Mq0hc.59128$ec1.8173@okepread01...
> Talked to the owner of a local shop today (Sooner Auto on AirDepot,
> Midwest City, OK). Good shop, I use them to fix my mom's 86 Merc.
> Especially when I'm up to my elbows in Jeep or just don't have the
> time/equipment.
>
> Asked about a local place that would clean/test injectors off the vehicle
> and they weren't aware of one but he did explain an interesting method to
> check injectors for proper (mostly proper) operation. You can't check
> the spray pattern this way but it might be a good idea if all the other
> rough idle solutions arn't working.
>
> Basically you pressurize the fuel rail then watch a pressure gauge
> hooked to the rail as you fire off one of the injectors. (The tricky
> part is the test gear that fires them for a set time in milliseconds).
> Wash, rinse, repeat for all injectors and that gives you the delivery
> for each. Compared with the factory spec you now know if they are
> delivering the proper amount of fuel. That indicates ones that are
> slow to close, plugged, or worn and needs replacing. (or possibly a
> good cleaning)
>
> I think one could build such a test rig with some simple RadioShack parts
> like a 555 timer and a power transistor. But it would take more time and
> money than just having them do it. Mebby if I run across an old injector
> to play with.
>
> What I need is a spare set so these can be shipped away, cleaing and
testing
> is about 1/6 the cost of a new injector.
>
> --
> DougW
>
>
>
>
>

Re: some useful? info on testing injectors
 

Sounds like a project for my electronic skills.

Can someone give me the low down on how these are triggered?

"DougW" <post.replies@invalid.address> wrote in message
news:Mq0hc.59128$ec1.8173@okepread01...
> Talked to the owner of a local shop today (Sooner Auto on AirDepot,
> Midwest City, OK). Good shop, I use them to fix my mom's 86 Merc.
> Especially when I'm up to my elbows in Jeep or just don't have the
> time/equipment.
>
> Asked about a local place that would clean/test injectors off the vehicle
> and they weren't aware of one but he did explain an interesting method to
> check injectors for proper (mostly proper) operation. You can't check
> the spray pattern this way but it might be a good idea if all the other
> rough idle solutions arn't working.
>
> Basically you pressurize the fuel rail then watch a pressure gauge
> hooked to the rail as you fire off one of the injectors. (The tricky
> part is the test gear that fires them for a set time in milliseconds).
> Wash, rinse, repeat for all injectors and that gives you the delivery
> for each. Compared with the factory spec you now know if they are
> delivering the proper amount of fuel. That indicates ones that are
> slow to close, plugged, or worn and needs replacing. (or possibly a
> good cleaning)
>
> I think one could build such a test rig with some simple RadioShack parts
> like a 555 timer and a power transistor. But it would take more time and
> money than just having them do it. Mebby if I run across an old injector
> to play with.
>
> What I need is a spare set so these can be shipped away, cleaing and
testing
> is about 1/6 the cost of a new injector.
>
> --
> DougW
>
>
>
>
>

Re: some useful? info on testing injectors
 

Sounds like a project for my electronic skills.

Can someone give me the low down on how these are triggered?

"DougW" <post.replies@invalid.address> wrote in message
news:Mq0hc.59128$ec1.8173@okepread01...
> Talked to the owner of a local shop today (Sooner Auto on AirDepot,
> Midwest City, OK). Good shop, I use them to fix my mom's 86 Merc.
> Especially when I'm up to my elbows in Jeep or just don't have the
> time/equipment.
>
> Asked about a local place that would clean/test injectors off the vehicle
> and they weren't aware of one but he did explain an interesting method to
> check injectors for proper (mostly proper) operation. You can't check
> the spray pattern this way but it might be a good idea if all the other
> rough idle solutions arn't working.
>
> Basically you pressurize the fuel rail then watch a pressure gauge
> hooked to the rail as you fire off one of the injectors. (The tricky
> part is the test gear that fires them for a set time in milliseconds).
> Wash, rinse, repeat for all injectors and that gives you the delivery
> for each. Compared with the factory spec you now know if they are
> delivering the proper amount of fuel. That indicates ones that are
> slow to close, plugged, or worn and needs replacing. (or possibly a
> good cleaning)
>
> I think one could build such a test rig with some simple RadioShack parts
> like a 555 timer and a power transistor. But it would take more time and
> money than just having them do it. Mebby if I run across an old injector
> to play with.
>
> What I need is a spare set so these can be shipped away, cleaing and
testing
> is about 1/6 the cost of a new injector.
>
> --
> DougW
>
>
>
>
>

Re: some useful? info on testing injectors
 

Sounds like a project for my electronic skills.

Can someone give me the low down on how these are triggered?

"DougW" <post.replies@invalid.address> wrote in message
news:Mq0hc.59128$ec1.8173@okepread01...
> Talked to the owner of a local shop today (Sooner Auto on AirDepot,
> Midwest City, OK). Good shop, I use them to fix my mom's 86 Merc.
> Especially when I'm up to my elbows in Jeep or just don't have the
> time/equipment.
>
> Asked about a local place that would clean/test injectors off the vehicle
> and they weren't aware of one but he did explain an interesting method to
> check injectors for proper (mostly proper) operation. You can't check
> the spray pattern this way but it might be a good idea if all the other
> rough idle solutions arn't working.
>
> Basically you pressurize the fuel rail then watch a pressure gauge
> hooked to the rail as you fire off one of the injectors. (The tricky
> part is the test gear that fires them for a set time in milliseconds).
> Wash, rinse, repeat for all injectors and that gives you the delivery
> for each. Compared with the factory spec you now know if they are
> delivering the proper amount of fuel. That indicates ones that are
> slow to close, plugged, or worn and needs replacing. (or possibly a
> good cleaning)
>
> I think one could build such a test rig with some simple RadioShack parts
> like a 555 timer and a power transistor. But it would take more time and
> money than just having them do it. Mebby if I run across an old injector
> to play with.
>
> What I need is a spare set so these can be shipped away, cleaing and
testing
> is about 1/6 the cost of a new injector.
>
> --
> DougW
>
>
>
>
>

Re: some useful? info on testing injectors
 

SB did pass the time by typing:
> Sounds like a project for my electronic skills.
>
> Can someone give me the low down on how these are triggered?

12v dc. They are just a solinoid powered by a fuse and grounded
through the ECU. The "short" test is to put 12V across the injector
pins and listen for a click.

Needless to say, not rated for constant duty. :)

Coil resistance is nominally 14.5 Ohms at 68 F

That would set the lower power requriement for any transistor
switching. I'd probably aim higher or fuse it just in case
you hook up to a sticky or shorted injector. (possibly current
limiting diode?)

Dunno.. sleepy. must go to real job in the morning.

--
DougW

Re: some useful? info on testing injectors
 

SB did pass the time by typing:
> Sounds like a project for my electronic skills.
>
> Can someone give me the low down on how these are triggered?

12v dc. They are just a solinoid powered by a fuse and grounded
through the ECU. The "short" test is to put 12V across the injector
pins and listen for a click.

Needless to say, not rated for constant duty. :)

Coil resistance is nominally 14.5 Ohms at 68 F

That would set the lower power requriement for any transistor
switching. I'd probably aim higher or fuse it just in case
you hook up to a sticky or shorted injector. (possibly current
limiting diode?)

Dunno.. sleepy. must go to real job in the morning.

--
DougW

Re: some useful? info on testing injectors
 

SB did pass the time by typing:
> Sounds like a project for my electronic skills.
>
> Can someone give me the low down on how these are triggered?

12v dc. They are just a solinoid powered by a fuse and grounded
through the ECU. The "short" test is to put 12V across the injector
pins and listen for a click.

Needless to say, not rated for constant duty. :)

Coil resistance is nominally 14.5 Ohms at 68 F

That would set the lower power requriement for any transistor
switching. I'd probably aim higher or fuse it just in case
you hook up to a sticky or shorted injector. (possibly current
limiting diode?)

Dunno.. sleepy. must go to real job in the morning.

--
DougW

Re: some useful? info on testing injectors
 

SB did pass the time by typing:
> Sounds like a project for my electronic skills.
>
> Can someone give me the low down on how these are triggered?

12v dc. They are just a solinoid powered by a fuse and grounded
through the ECU. The "short" test is to put 12V across the injector
pins and listen for a click.

Needless to say, not rated for constant duty. :)

Coil resistance is nominally 14.5 Ohms at 68 F

That would set the lower power requriement for any transistor
switching. I'd probably aim higher or fuse it just in case
you hook up to a sticky or shorted injector. (possibly current
limiting diode?)

Dunno.. sleepy. must go to real job in the morning.

--
DougW

Re: some useful? info on testing injectors
 

Be careful, some injectors are called Peak and Hold. Basicly, the injector
takes a higher current to open, then needs a lower current to keep it open.
If you supply to much current to this type of injector you will overheat it
and burn it out.

http://www.msdignition.com/fuel_3.htm

Kelly

"DougW" <post.replies@invalid.address> wrote in message
news:oj1hc.59330$ec1.43830@okepread01...
> SB did pass the time by typing:
> > Sounds like a project for my electronic skills.
> >
> > Can someone give me the low down on how these are triggered?
>
> 12v dc. They are just a solinoid powered by a fuse and grounded
> through the ECU. The "short" test is to put 12V across the injector
> pins and listen for a click.
>
> Needless to say, not rated for constant duty. :)
>
> Coil resistance is nominally 14.5 Ohms at 68 F
>
> That would set the lower power requriement for any transistor
> switching. I'd probably aim higher or fuse it just in case
> you hook up to a sticky or shorted injector. (possibly current
> limiting diode?)
>
> Dunno.. sleepy. must go to real job in the morning.
>
> --
> DougW
>
>