My car just stopped while going up a hill and would not restart. A mechanic told me it was probably the ignition coil or the ignition control unit. I replaced the ignition coil, the cheaper of the two parts, and my car still didn't start. From the posts in the forum, it sounds like it could be the fuel pump relay. Can anyone tell me where the fuel pump relay is on an 86 420 SEL? Does anyone have any advice on what may be the problem?

 

it is very easy to check both of those problems.

you only need to unplug #1 igniton cable, put an old spark pplug on it, ground it, then crank the engine to see if there is any spark. make sure the crankshaft position sensor is okay. this signal goes to ignition module.

fuel....put a fuel pressure gauge on it. it must be above 3 bars.

the fuel pump relay is somewhere near the firewall.

 

I had to replace both fuel pumps on my '86. I put about 1/4 cup of gas in the intake, and it started momentarily, so I knew I had ignition and it was lack of fuel. I guessed it was the fuel pumps, and was correct. I should have checked the relay first, as it cost less to replace. I was going to replace the pumps anyway, in an attempt to prevent inconvenient failure. Replace the filter while you're at it.