no start when rain

[chromatin]

1991 pontiac grand am le coupe 2.3L quad4

when it rains (or when it is very humid), the car will have a difficult first start in the day or, even no start at all. When it decides not to start, it even doesn't click. However, this problem can be solved by opening the door and shutting the door heavily. After the first start, it usually has no problem in that day. The car has no problem in dry days.

Any thought about the problem? Thank you very much!

[4kQuad]

First guess, the battery connections are dirty, slaming the door may wiggle the wires just enough to make the contact it needs to start.

Also they may just be loose. But start with cleaning the battery and the connectors that hook to it.

The click is a sign not enough power is getting to the starter, and when there is no click even less power is reaching the starter.

Post back after trying that.

[Matt95GT]

Originally posted by 4kQuad
First guess, the battery connections are dirty, slaming the door may wiggle the wires just enough to make the contact it needs to start.

Also they may just be loose. But start with cleaning the battery and the connectors that hook to it.

The click is a sign not enough power is getting to the starter, and when there is no click even less power is reaching the starter.

Post back after trying that.

I agree. High humidity will often trigger any conductivity issues with the battery terminals.

[chromatin]

well, the battery connections looked clean actually. But I did further clean them. Let's wait until next rain.

[Y2KGPGT]

How old is the battery? It might be time to replace it.

[chromatin]

well, the battery was determined to be weak this weekend and a new one was installed. Let's wait and see.

[chromatin]

OK, with the new battery, the car was fine for 4 months in Colorado. It was dry most of the time in these 4 months but there were several humid days but the car was fine. Always easy start. We traveled to Texas during Christmas holiday and the problem was back. Right there it was pretty humid. Again we had to jiggle the car to start it. Interestingly, at one time I happened to shift the lever from P to N (oh, by the way, it's a 3 speed auto) and it started. This phenomenon does point to a bad neutral safety switch, but most of the time by shifting it from P to N, it didn't do the work. In this month in Colorado, it's fine again and it's pretty dry until today. OK, it's somewhat humid now and it didn't start without jiggling. Here are some facts and some of my own analysis. Please feel free to chime in. Thank you very much! I really want to exactly pinpoint the problem before doing anything. You know it's still pretty cold outside and I have to work on it in an open parking lot.

1, Battery is fine. It's 5 months old and I have it tested in Autozone. Alternator is fine too. The connectors on the battery are super clean. So no problem with the battery. I bet you will agree.


2, Neutral safety switch (NSS) might be bad. Here is what's in my mind. At least sometimes shifting the lever does the job, so NSS might be bad. Also jiggling might very well just make the connection inside the switch better. But most of the time, the trick doesn't work. So it might be fine. What do you think? Should I consider it as a possibility at all?

3, Starter is dying. Well, I think this is most likely the case. From what know, jiggling and starting is a typical phenomenon of a bad starter. The problem is, whenever the car can start, it starts really easily, including the those starts after jiggling. Isn't that odd if the starter is dying?

Also the locations of the starter sucks. From the manual, I have to take off quite some stuffs to replace the starters. I really don't want to touch it until I (with your help) can rule out the possibility of a bad NSS.

4, Connectors on the starter and the grounds around it. Well, unfortunately, it seems to me that it requires the same labor to see those things as to replace a starter. So I don't know.

[4kQuad]

When I replaced mine I made a post in the how to part of the site.
If you dercide to change it out, you may want to read it over a time or two. 1989 2.3 DOHC Mine was 5 speed, but that shouldn't make a differance with the starter.

http://www.gaownersclub.com/forum/showthread.php?s=&threadid=25807

Link to my thread.

[cocobob]

Old ignition cables can absorb humidity adding to their allowable resistance. Take off your longest cable and see if the resistance is over 25k ohms. If so replace cables. use dielectric grease on boots to plugs.

Cheers

[chromatin]

Are you talking about spark plug wire? It uses intergrated direct ignition. So no such things, I think. Also can these things prevent the car from cranking at all? I don't think so. But my car would not even click (and of course, no crank either) at all when it doesn't start.

[4kQuad]

To click the starter needs power from the battery to reach it. To turn the motor over the battery has to send full power to the starter. If you have dirty wires, dieing battery, dieing starter it may not spin, but the lights on the car will dim big time when you try to start it.

Right, Quads have no spark plug wires, they do have boots. well that's what there called. And Spark has Nothing to do with the motor spinning. Once it is spinning it needs spark to fire up and run.


Try another battery in it if you can or clean the ^%*^&*& out of your connections.