Car won't crank intermittently

[rcfanatic]

I read through a bunch of no start threads and couldn't find a similar problem so here goes.

About every 5th start, I'll turn the key, hear the starter solenoid click, and then nothing happens. If I get a jump it starts immediately. I can also push start the car just fine.

I have 2 *new* main relays, and sometimes swapping these in an out will allow it start, sometimes not. I always have 11.9V at the main relay's pin 30 when the key is in the ON position.

Battery and starter are 14 months old. I checked the continuity across the fusible link and it is fine.

The only other thing I can think of is the ignition switch, but I don't know why swapping relays around would help. Any thoughts?

[jlevie]

The first thing to check is what the system voltage is when the starter only clicks. If the battery is fully charged that will be 12.7v. A battery voltage below 12.4v may not be enough to start the car.

The main relay has nothing to do with operation of the starter in the stock configuration.

[rcfanatic]

I guess that's it. The battery voltage is only 12.0V when it doesn't want to crank. It's just odd that fiddling w the relays or repeatedly trying to start it works occasionally. Also today it happened twice while I was running errands, so it's not like the battery has been sitting for long periods when it doesn't crank.

The voltage reads 13.5V when it's idling at 700rpm

Is it safe to say the battery needs to be replaced? It's a red top optima that I bought last October


Edit: Bought last December

[jlevie]

It doesn't sound like the cause is the battery, and if you have 13.5v at idle the alternator may be okay. The system voltage should rise to about 14v at 2500rpm and should not drop much when you add the load of the headlights and HVAC blower set to max.

I would say that the likely cause is just a bad connection, or excessive battery draw when the car is off. But if it happened while running errands with little time off and the battery voltage fell to 12.0v, the alternator becomes more of a suspect.

[rcfanatic]

Well I went ahead and replaced the battery (3 yr warranty), so we'll see what happens with this new one. Thanks for the input

[Jaxx_]

Well I went ahead and replaced the battery (3 yr warranty), so we'll see what happens with this new one. Thanks for the input

I doubt the battery is the problem. you can test the load on the battery with the car off with a multimeter. An easier way to test it is to unhook a battery lead when not in use and see if there is any difference.

Is the car sitting for any particularly long period of time between these cranks?

[rcfanatic]

I doubt the battery is the problem. you can test the load on the battery with the car off with a multimeter. An easier way to test it is to unhook a battery lead when not in use and see if there is any difference.

Is the car sitting for any particularly long period of time between these cranks?

I drive the car at least every other day, but usually short ~ 10 min trips.

Example: I ran errands today and stopped at 6 places. The 5th place, I had to swap the main relay out twice before it would crank. The 6th place I tried swapping the relay several times to no avail, kept trying to crank it and after about 3 minutes it spontaneously cranked and started. The car didn't sit more than 15 minutes at any stop.

It could be the alternator, but I replaced it back in fall '08, so I can't imagine it would have gone bad already. I'll have to check it's output at a higher rpm

[rcfanatic]

I know Jim said that the main relay doesn't affect the starter but it seems too coincidental that literally pulling out one relay and putting in another will allow the car the start immediately, in some cases. The car will never restart on it's own. I must swap relays, push start, or jump it

[jlevie]

If the engine cranks, but doesn't fire, the main relay is a possibility (or the fuel pump relay). But if the starter only clicks, that can't be the main relay.

[Jaxx_]

are all your grounds okay?

[rcfanatic]

are all your grounds okay?

Where should I check aside from the starter and alternator

[jlevie]

Check the main power connections at the battery, power point in the engine bay and at the starter. The relevant grounds are from the engine to the frame and from the battery to the car.

[rcfanatic]

Everything looked good except the ground from the valve cover to the body was unhooked, so fixed that. I imagine this happened a couple days ago when I adjusted my valves.

Later on, for the first time, the car would not start even while getting a jump. The battery was at 13V and the car would not start. Stood around for 3 minutes discussing how to push start the car, try to start it again (without a jump or pushing) and it fires right up.

This is driving me crazy... So there's no way it can be the ignition switch?

[jlevie]

The ignition switch would be a possibility if the starter doesn't at least click. If it does, a main power/ground problem or a bad starter are the likely candidates. But is is easy enough to check the solenoid control signal with a meter to see that system voltage is being applied to the starter solenoid when it misbehaves.

[Jaxx_]

check for 12V at the starter with the (i guess) black and yellow wire when the key is in start. Like jim said, if the starter is at least clicking it's probably not the ignition switch.