Start problems when it rains...

EMJ · 11-26-2009, 07:43 AM

So my '88 3.2 has been having trouble starting when it rains. Car turns over but won't start. DME relay is new, alternator and battery are new. Took to the best P-Car shop in the area, but of course it started up and was fine so they couldn't diagnose. Problem is that this has occurred twice now in the past 4 months and it simply won't start until time has elapsed, as in days have elapsed. This only occurs when the car is driven in the rain, or left out in the parking lot in the rain.

Car has new plug wires, coil wires have been checked - checked out fine - and again, alternator and battery are new. A giveaway that the car may not start is when the radio suddenly turns off while driving. Chances are that either that day or the next day, the car will turn over when the key is turned, but won't start when I try to start it the next time I get in the car. For clarification, the car doesn't turn off and not re-start while driving. It's only when the car is turned off that it won't restart.

Here's the rub: The car has an Autothority Mass Flow and chip that have been in the car for at least 5 years. This is the only thing my wrench and I can come up with that may be causing the issue. Any ideas?

Your help is much appreciated, as always. Thanks!

paulgtr · paulgtr's Garage

your distributor cap is not closed tight. open it up, dry it off and close it correctly. should solve it

TopsailBeach · TopsailBeach's Garage

I had the same problem exactly as you described, except the up/down driver seat motor wouldn't work instead of the radio when the no start condition occurred.

You didn't mention if you have checked the grounds--that was part of my problem. Do that first. Remove, clean and reinstall the grounds at the battery, on the fuel rail and on the transmission. Sometimes the battery and transmission straps need replacing but not often. Then check with a voltmeter the resistance on pins 5, 16, 17, 19, 28 on the DME harness. There should be minimal resistance.

In my case, after working through the grounds, the issue was resolved (at least the issue of the engine not starting and the seat not moving at the same time). However, I had multiple coincidental issues as well resulting in a no start condition. If your grounds are fine and test okay, it's a whole different game including testing/replacing sensors, testing the fuel injector circuit, and the DME unit. Been there and just done that as well.

Good luck--

Looking_for_911 · 11-26-2009, 02:42 PM

Quote:

Originally Posted by paulgtr

your distributor cap is not closed tight. open it up, dry it off and close it correctly. should solve it

I know it ain't "apples to apples" but this is what I thought having had the same kind of problem on a '67 Chevelle I once owned.
Good luck.

bgmilner · 11-26-2009, 02:56 PM

I too have an 88 3.2 and I agree with the other poster who suggested dist cap.
My cap had a very very fine crack in it, invisible to the naked eye. I had a couple of months where every time it rained, my car would run badly. Replacing the cap solved the problem.

Thank, Brian

StayGold808 · 11-26-2009, 06:28 PM

I had the same problem. Turned out to be the distributor cap.

Quicksilver · 11-26-2009, 09:45 PM

This seems to be a common complaint with the ignition. A clean dry cap is important but there are a few additional things you can do to make it bullet proof (or scuba proof

).
- Carefully test all the wires. I have seen new wires from reputable companies that have problems out of the box.
- Use dielectric grease to seal all boots to the cap, plugs. and coil.
- Use dielectric grease to seal the boots to the wire. (This is the detail people forget.)
- Use a bit of dielectric grease to help seal the cap to the distributor.
Note that all of this sealing will hold air pressure under the boots which will tend to make them try to pop right back off!

After a failure like this it is common to see carbon tracks inside and outside the distributor cap because of the previous 'voltage leak' and this can make the slightest bit of water set it off again. Give it a very careful inspection. Anything that isn't a perfect surface on the cap is a problem and the easy fix is to toss it and make the rest of the system perfect so it doesn't happen again.

One additional thing we used to do when running is really bad conditions was to give the installed wires a light sprayed coating with a dry silicone lube. This should be done before the problem with everything perfectly dry and clean. This can help make water repelled from the wires. I haven't had to do this on my Carrera but it is a step you can take for severe conditions.

I have never had moisture problems because I went through and prepped the wires the week I got my car and I love driving it in the rain. (The defrosting is less then perfect in a good soaking though...)

EMJ · 11-29-2009, 09:04 AM

I just installed a new distributor cap and rotor this morning. Hoping this will take care of the issue. I also checked my grounds around the battery and they look good.

Thanks a bunch for all of the advice and tips - I appreciate it! Keep you posted!

stlrj · 11-30-2009, 07:03 AM

Quote:

Originally Posted by EMJ

I just installed a new distributor cap and rotor this morning. Hoping this will take care of the issue.

It might help, but it still remains...your distributor cap is not water tight which means water will always find a way inside your distributor ( capillary action where the cap meets the distributor) whenever it gets wet. Until you seal that off, you will always have a problem.

After sealing mine, I no longer have problems in the rain.

Cheers,

Joe
74 911 w/ 86 3.2

EMJ · 11-30-2009, 06:15 PM

Quote:

Originally Posted by stlrj

It might help, but it still remains...your distributor cap is not water tight which means water will always find a way inside your distributor ( capillary action where the cap meets the distributor) whenever it gets wet. Until you seal that off, you will always have a problem.

After sealing mine, I no longer have problems in the rain.

Cheers,

Joe
74 911 w/ 86 3.2

Joe,
What'd you use to seal it? Nice pic, btw.

stlrj · 06:17 AM

Quote:

Originally Posted by EMJ

Joe,
What'd you use to seal it? Nice pic, btw.

Ultra Grey.

EMJ · 12-06-2009, 09:38 AM

"...capillary action where the cap meets the distributor."

This makes a lot of sense but I want to ensure I understand. Are you saying apply sealant inside the cap where it meets with the distributor to seal it off? I've also read that it's a good idea to apply lubricant to where the plug wires and distributor cap meet to keep out moisture. Is Ultra Gray recommended for this as well?

Thanks!

stlrj · 06:34 AM

Ultra Grey ( local auto parts store ) is a sealant like silicon, but unlike most silicon sealers, it remains soft enough to remove later. Only apply on the cap to distributor mating surface.

http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_makers/auto_Permatex_Ultra_Grey_Rigid_High-Torque_RTV_Silicone_Gasket_Maker.htm