codycool55

Hello everyone. My 1989 300 SE was running fairly well for a long time. I let it sit outside for 2 days during which it rained, and it hasn't started since. It has been raining on and off and cold since this problem. I have been troubleshooting it, and I have a few problems eliminated.

I had a 4 year old battery. The engine turned over fine the first couple of times I attempted to start it, but the next day the battery failed and would not hold a charge. I took it to NAPA to get it tested, and it was a bad battery so I replaced it, and the engine is now cranking fine.

I checked the fuse box, and I could see no blown fuses. I wiggled each one around a little to make sure they are seated well, but this did not help. I removed the air filter houing and found no loose or disconnected wires or hoses.

The fuel pump and line is functioning. I loosened the fuel line where it meets the distributor just enough to see fuel squirt out to confirm this.

Upon recommendation of a previous owner who spoke to a mechanic I squirted a small amount of carburetor cleaner into the air intake (I think that's the name. Under the brownish metal circle under the air filter) let that sit, then poured a small amount of gasoline in and tried starting it, but this did not help. I also tried using starter fluid but this did not help either.

I know the car was running a little on the lean side as I had it adjusted to do so, so I tried to richen up the mixture. I'm not sure if the mixture is optimal. I know it is possible to test the mixture using methods found here when the car is running, but will this work when the car will not start?

I have yet to test for spark, but the plug wires do seem a bit worn and corroded. The spark plugs were replaced within the last year, and I do not think they need to be replaced, however it is not out of the question.

Short version: After sitting in rain and cold car will not start. Car is cranking and turning over, but not firing. Fuel is reaching distrubutor. Battery is not an issue. Fuel mixture might be off. Plug wires are questionable.

Can I test fuel mixture without the car running? Any ideas tips or help getting this car running?

Thank you!

vteodossievv@ya

to start the car y need 1.fuel 2.spark 3.gas. check all 3

vteodossievv@ya

sorry 3 . air

Tony Funches

Please pull a spark plug & examine it; black and sooty is rich, bright white is too lean, tan is good.
It seems as though the prob is spark related, so if the plugs are good, check the ign rotor; is it carbonized & or showing other evidence of failure?
Also check the interior of the cap for the same, as well as cracks or other damage.
If that checks out attach a timing light and see where the strobe flashes; the result CAN indicate whether cam timing is off,
Checking the COIL can be a Root-Canal experience, but it can't be ruled out ...
use this checklist & then "lettuce" know what you find! Cheers ...

codycool55

My car seems to have all 3. Any specific ways to test each one?

I tested the ignition system by disconnecting the plug wires and connecting them to a brand new spark plug then laying it on the engine block and attempting to start it. I checked each plug wire and they all had spark, but some seemed like the spark was a little weak. Soon I will take out each spark plug and check their condition.

Can I test the fuel/ air mixture as it currently is set without having the car running?