What would cause a car to not start when it's humid ?

[user removed]

When you find the cause, it might be outside the passenger compartment, but in either case, humidity inside a car is basically the same as outside. You will get it figured out and learn that that car can't beat you that easily. The most important knowledge is not knowledge at all, just boneheaded perseverance. "I will kick that problems arse". The real question is how bad will it beat me up before it surrenders!

[Cd]

[QUOTE=Old Mechanic;272987]"Circuit tripped" means you have made a connection that works without the relay in the circuit and the fuel pump works?

Maybe i used the wrong wording. I place a jumper wire in the #5 and #7 terminals as shown in the Chilton guide. I hear the fuel pump stay on constantly but the car still will not start ( and there is spark, though weak ).

That can cure the problem temporarily but remember the fuel pump will run continuously, even with the key out of the ignition switch.

That's odd. I have to have the car turned to ACC to hear the pump stay on.

Don.t leave it that way or it will kill your battery, but it should make the car drivable.

As stated above, the car still will not start as odd as that is.

I have seen one Mercedes with 4 ignition switches replaced. The woman owned 100 vending machines and kept all of the keys hanging from the ignition switch. Once she separated all the vending machine keys from the key she used to start the car her problems ended.

I have since stopped using the wad of keys. ( around six months ago actually ) There is play in the switch, but not that much. Nothing that i would think of as 'loose'.

regards
Mech

[user removed]

The loose part is the mechanical portion of the ignition steering column lock. The electrical part (at least on Nissan's) was a separate switch mounted to the back of the steering column lock.

The weak spark may also be related to the ignition switch, so that points to the switch as the most likely suspect. In some cases when the mechanical lock gets sloppy (as you described) it MAY cause the connections in the electrical portion to not line up properly.

Most ignition circuits use battery voltage for starting then use some resistance to keep the voltage lower when the engine is running. Is the spark stronger when (and if) it is running assuming you can get it running.

When you have two separate things that are not working properly, then the most likely cause is the source of voltage to those two separate things. One would be the ignition switch, the other would be battery and or grounds. That not an absolute statement but a most probable cause. It's why these things can be so damn frustrating.

regards
Mech

[user removed]

I would not worry about the pump running with the switch on accessory and not when the key is out of the switch. I may be there is another relay powering up instead of the pump circuit going directly to the battery. My knowledge of Honda's is not that specific so for the time being don't get to concerned with that.

I have seen a leaky windshield dump water on the ECU and fire up the pump and the ground circuit to the injectors in a 300 ZX. When the car was towed to us 4 gallons of fuel had been pumped into the engine and it was liquid locked with fuel in the cylinders and the cranckcase was full of gas!

regards
Mech

[Cd]

I had the car running the other day and tested the spark.

It was identical to when the car will not start.

The battery cable was very corroded once i pulled back the rubber casing.
I replaced it and thought this would possibly be the cause of the problem, but the car just seemed to rev stronger.
I bought a piece of thick gauge wire and im going to ground the hell out of this thing !

I asked on the Honda forums about testing ignition switches, and they said that i should see the warning light come on and stay on for a second or two when i turn the key. Also, if i pull up the emergency brake, the light is supposed to stay on.
Are you aware of any other tests for the switch ? ( it passed the signal light testing )

[Cd]

I'll deal with this tomorrow. Thanks for all the help Mech.

[user removed]

The more I think about it the more I wonder why the pump would work when the ignition switch was in the accessory position. Honda forums usually have a couple of real pros who have more Honda specific knowledge than myself.

I would check the voltage at the positive terminal of the ignition coil, it should be close to battery voltage under the same conditions.

Also if you have the car running check the voltage at the battery to see if the charging system is working properly.

If you want to get the electrical portion of the ignition switch and it is not too expensive it might be a good shot to replace it. We had them in stock at my old Nissan shop so we could just plug in a new one and see if it solved the problems.

Or, you could check for voltage drops at the ignition switch (remove bottom cover of the steering column). A voltage drop is almost certainly the best evidence of finding the real source of your problem, since ignitions switches are not supposed to have any resistance to create a voltage drop.

You have determined that the fuel pump is not the only problem and the spark is weak. I think you have already replaced the distributor and plugs. The old plugs were cruddy and had a large gap. How about the ignition wires and the coil?

See if the coil wire has a good spark compared to the plug wires themselves. If so then its in the cap and plug wires. If not it's probably the coil or low voltage to the coil.

regards
Mech

[user removed]

Originally Posted by Cd

I had the car running the other day and tested the spark.

It was identical to when the car will not start.

The battery cable was very corroded once i pulled back the rubber casing.
I replaced it and thought this would possibly be the cause of the problem, but the car just seemed to rev stronger.
I bought a piece of thick gauge wire and im going to ground the hell out of this thing !

I asked on the Honda forums about testing ignition switches, and they said that i should see the warning light come on and stay on for a second or two when i turn the key. Also, if i pull up the emergency brake, the light is supposed to stay on.
Are you aware of any other tests for the switch ? ( it passed the signal light testing )

Make sure both positive and negative battery terminals are clean (cables removed) and clean the inside of both cables where they contact the terminals on the battery. Also make sure the other ends of both battery cables are clean and tightly connected to their respective components.

regards
Mech

[Cd]

Today it rained and rained ...and rained, so I didn't do much of anything.

I tried to test the distributor, but rain was actually hitting the distributor ( no garage remember ?) So I quit for the day.

Off the wall question here : I have a SuperMID that has one wire connected to an injector. I removed it just as a test and it did nothing, but could something like that cause any sort of problems ? It looked like possibly a slight oxidation on the bare wire of the injector where i spliced in the SuperMID wire. I had it covered in electrical tape and I may just be seeing glue ( it was raining and i didn't look very hard. )

[Cd]

Today i tested the alternator, specifically the ICM.
It checks out fine with over 11.5 volts.

( battery is getting weak from the testing )

The car still fails to start with the main relay jumped. I can hear the fuel pump kick on and stay on, but the car just revs.