I have '90 240 DL and recently when it got to around zero degrees out, it would't start. It seems that I have intermittent spark and even when I get spark to the plugs, it seems weak (whitish - should be blueish).

I have checked the 15 terminal on the coil and have 12v to it. I also checked the 25 amp fuse on the fender and cleaned it up a bit. Still the spark is intermittent and weak and the car still doesn't start.

Also, I am getting gas as I can smell fuel at the exhaust.

Any ideas as to what else to check?

 

Well white and blue sparks are both strong spark colors, does the spark look weak, as in small? How's your ignition doing, as in the place where you put your key?

 

Thanks for the reply...

If a yellow spark is ok, then I guess that it is strong enough. It would arc ~1/8 - 1/4 inch so I guess that would be considered strong.

However, it seems intermittent when cranking - sometimes I get it, others not. Another interesting thing I noticed was that the speedometer was reading ~30 mph when cranking. It goes back to zero when I stop. This is odd and the more I thought about it, I am thinking bad ground somewhere. The connection to the battery is nice and clean so it isn't there. Tomorrow I'll check the other connections.

Also, I will check various connections (such as the crank position sensor connector right at the firewall) and clean them up

 

Well, I ran through all of the electrical connections in the engine compartment, cleaned them with contact cleaner and coated them with dielectric grease. Replaced plugs (they were really fouled) and wires. Checked the spark - no longer intermittent.

Tried to start but still no start. It backfired a couple of times so I was thinking that timing was off. My thought was to check the timing belt.

Pulled off the upper timing belt cover and found the belt really loose. I aligned the mark on the camshaft and checked the crankshaft - it lined up as well. Couldn't see the alignment on the intermediate shaft pulley so I took off the distributer cap and checked the rotor - it was positioned between 1 & 3. This told me that the intermediate shaft was off.

Pulled the crank pulley and the lower timing belt cover and it was obvious that the intermediate shaft was off 2-3 notches. After unloading the tensioner bearing, it was shot which explains why the belt was so loose.

Cause of the problem found. Now just have to wait for the parts and put it all back together.