90 Jetta, won't start in rain.

Changed coil, covered hood vent, put weatherstripping between
hood and body at firewall area. Been covering most of it
with a tarp in rainy condx. I swapped computers, a third coil (new)
checked voltage at injectors (led), cleaned some ground connections.
Did find water on the hump behind the console center by firewall.
Fuel pumps run. It's all or nothing, typically won't start
after a rainy night. A day of dry weather and it's ready to go.
Checked front sunroof drains with lung air, seem open.
There's no headliner so I can somewhat see things, such as,
the tubes are connected. Also, I seem to have spark under these
condx. Havn't checked fuel pressure, but like I say, it's all or
nothing, and the fuel pumps do run, and shut off as they should
when engine doesn't start.... these things have improoved it,
but yesterday morning I let some heavey rain hit it before getting
the tarp on, and it sat in wet area with rain overnight and
presto, she no start.

would appreciate any pointers
Les

PeterD wrote:
> On Tue, 28 Sep 2010 18:43:40 +0800, > wrote:
>
>> Changed coil, covered hood vent, put weatherstripping between
>> hood and body at firewall area. Been covering most of it
>> with a tarp in rainy condx. I swapped computers, a third coil (new)
>> checked voltage at injectors (led), cleaned some ground connections.
>> Did find water on the hump behind the console center by firewall.
>> Fuel pumps run. It's all or nothing, typically won't start
>> after a rainy night. A day of dry weather and it's ready to go.
>> Checked front sunroof drains with lung air, seem open.
>> There's no headliner so I can somewhat see things, such as,
>> the tubes are connected. Also, I seem to have spark under these
>> condx. Havn't checked fuel pressure, but like I say, it's all or
>> nothing, and the fuel pumps do run, and shut off as they should
>> when engine doesn't start.... these things have improoved it,
>> but yesterday morning I let some heavey rain hit it before getting
>> the tarp on, and it sat in wet area with rain overnight and
>> presto, she no start.
>>
>> would appreciate any pointers
>> Les
>
> Well, let's see, you have swapped a bunch of parts without doing good
> diagnostics...
>
> Are you actually getting a spark at the plugs when the no-start
> happens?
>
> Have you put a scan tool on it and checked live data when the no-start
> happens? What results did you get?

Did have spark the one time I tried. Car ran with alternate parts...
till the next rain. I'll have to look into a scan tool for an A2...

Thanks
Les

John Henderson wrote:
> IRv wrote:
>
>> Changed coil, covered hood vent, put weatherstripping between
>> hood and body at firewall area. Been covering most of it
>> with a tarp in rainy condx. I swapped computers, a third coil (new)
>> checked voltage at injectors (led), cleaned some ground connections.
>> Did find water on the hump behind the console center by firewall.
>> Fuel pumps run. It's all or nothing, typically won't start
>> after a rainy night. A day of dry weather and it's ready to go.
>> Checked front sunroof drains with lung air, seem open.
>> There's no headliner so I can somewhat see things, such as,
>> the tubes are connected. Also, I seem to have spark under these
>> condx. Havn't checked fuel pressure, but like I say, it's all or
>> nothing, and the fuel pumps do run, and shut off as they should
>> when engine doesn't start.... these things have improoved it,
>> but yesterday morning I let some heavey rain hit it before getting
>> the tarp on, and it sat in wet area with rain overnight and
>> presto, she no start.
>
> These are classic symptoms of humidity-induced shorting-to-ground
> of the high tension pulse.
>
> Has the car been in a salt-laden environment? Wipe clean all
> ignition leads and exposed insulators (spark plugs, distributor
> cap, etc).
>
> Otherwise try replacing the distributor cap and rotor.
>
> Just because you're seeing a spark across a removed spark plug at
> atmospheric pressure, this doesn't mean there'll be a spark
> happening at compression pressure of around 8 times atmospheric.
>
> John

Yes this is salty Connecticut. And yes it doesn't take much rain,
just the humidity and it's a wet parking spot at the base of a steep
hill. I will try what you suggest and thank you very much.

Les

John Henderson wrote:
> IRv wrote:
>
>> Changed coil, covered hood vent, put weatherstripping between
>> hood and body at firewall area. Been covering most of it
>> with a tarp in rainy condx. I swapped computers, a third coil (new)
>> checked voltage at injectors (led), cleaned some ground connections.
>> Did find water on the hump behind the console center by firewall.
>> Fuel pumps run. It's all or nothing, typically won't start
>> after a rainy night. A day of dry weather and it's ready to go.
>> Checked front sunroof drains with lung air, seem open.
>> There's no headliner so I can somewhat see things, such as,
>> the tubes are connected. Also, I seem to have spark under these
>> condx. Havn't checked fuel pressure, but like I say, it's all or
>> nothing, and the fuel pumps do run, and shut off as they should
>> when engine doesn't start.... these things have improoved it,
>> but yesterday morning I let some heavey rain hit it before getting
>> the tarp on, and it sat in wet area with rain overnight and
>> presto, she no start.
>
> These are classic symptoms of humidity-induced shorting-to-ground
> of the high tension pulse.
>
> Has the car been in a salt-laden environment? Wipe clean all
> ignition leads and exposed insulators (spark plugs, distributor
> cap, etc).
>
> Otherwise try replacing the distributor cap and rotor.
>
> Just because you're seeing a spark across a removed spark plug at
> atmospheric pressure, this doesn't mean there'll be a spark
> happening at compression pressure of around 8 times atmospheric.
>
> John

Hey thanks again I cleaned the wires, tops of plugs sites where wires
connect, inside cap... she runs. Tomorrows a monsoon and I'm pretty
sure she'll be fine. I let my wife know she married an idiot.
Les

On Tue, 28 Sep 2010 18:43:40 +0800, IRv > wrote:

>Changed coil, covered hood vent, put weatherstripping between
>hood and body at firewall area. Been covering most of it
>with a tarp in rainy condx. I swapped computers, a third coil (new)
>checked voltage at injectors (led), cleaned some ground connections.
>Did find water on the hump behind the console center by firewall.
>Fuel pumps run. It's all or nothing, typically won't start
>after a rainy night. A day of dry weather and it's ready to go.
>Checked front sunroof drains with lung air, seem open.
>There's no headliner so I can somewhat see things, such as,
>the tubes are connected. Also, I seem to have spark under these
>condx. Havn't checked fuel pressure, but like I say, it's all or
>nothing, and the fuel pumps do run, and shut off as they should
>when engine doesn't start.... these things have improoved it,
>but yesterday morning I let some heavey rain hit it before getting
>the tarp on, and it sat in wet area with rain overnight and
>presto, she no start.
>
>would appreciate any pointers
>Les

Well, let's see, you have swapped a bunch of parts without doing good
diagnostics...

Are you actually getting a spark at the plugs when the no-start
happens?

Have you put a scan tool on it and checked live data when the no-start
happens? What results did you get?

IRv wrote:

> Changed coil, covered hood vent, put weatherstripping between
> hood and body at firewall area. Been covering most of it
> with a tarp in rainy condx. I swapped computers, a third coil (new)
> checked voltage at injectors (led), cleaned some ground connections.
> Did find water on the hump behind the console center by firewall.
> Fuel pumps run. It's all or nothing, typically won't start
> after a rainy night. A day of dry weather and it's ready to go.
> Checked front sunroof drains with lung air, seem open.
> There's no headliner so I can somewhat see things, such as,
> the tubes are connected. Also, I seem to have spark under these
> condx. Havn't checked fuel pressure, but like I say, it's all or
> nothing, and the fuel pumps do run, and shut off as they should
> when engine doesn't start.... these things have improoved it,
> but yesterday morning I let some heavey rain hit it before getting
> the tarp on, and it sat in wet area with rain overnight and
> presto, she no start.

These are classic symptoms of humidity-induced shorting-to-ground
of the high tension pulse.

Has the car been in a salt-laden environment? Wipe clean all
ignition leads and exposed insulators (spark plugs, distributor
cap, etc).

Otherwise try replacing the distributor cap and rotor.

Just because you're seeing a spark across a removed spark plug at
atmospheric pressure, this doesn't mean there'll be a spark
happening at compression pressure of around 8 times atmospheric.

John

Irv > wrote:

>Hey thanks again I cleaned the wires, tops of plugs sites where wires
>connect, inside cap... she runs. Tomorrows a monsoon and I'm pretty
>sure she'll be fine. I let my wife know she married an idiot.

A good slathering of dielectric grease around the inside of
the spark plug boots will help keep moisture from getting to the metal
connectors and causing corrosion. I use the stuff in most every
electrical connection under the hood to keep water out.

Todd

Irv wrote:

> Hey thanks again I cleaned the wires, tops of plugs sites where wires
> connect, inside cap... she runs. Tomorrows a monsoon and I'm pretty
> sure she'll be fine. I let my wife know she married an idiot.

Good news. If you have further problems, there could be a
hairline crack in the distributor cap or rotor. A trace of salt
in there will absorb moisture and short out when very humid.

And plug leads are service items. They have a fairly long life,
but need replacing some times.

John

wrote:
> > wrote:
>
>> Hey thanks again I cleaned the wires, tops of plugs sites where wires
>> connect, inside cap... she runs. Tomorrows a monsoon and I'm pretty
>> sure she'll be fine. I let my wife know she married an idiot.
>
> A good slathering of dielectric grease around the inside of
> the spark plug boots will help keep moisture from getting to the metal
> connectors and causing corrosion. I use the stuff in most every
> electrical connection under the hood to keep water out.
>
> Todd
Yup there was salt up in there. Thanks much and I'll look into the
grease. Les

Good minds come together and solve a problem. Nice.