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

Reply to
IRv
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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

Reply to
Irv

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

Reply to
Irv

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

Reply to
Irv

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?

Reply to
PeterD

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

Reply to
John Henderson

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

Reply to
racertod

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

Reply to
John Henderson

Yup there was salt up in there. Thanks much and I'll look into the grease. Les

Reply to
Irv

Good minds come together and solve a problem. Nice.

Reply to
B Briggs

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