My dad has an '86 420 SEL which starts and then dies. He read on other forums online that it might be the fuel filter, which turns out it'snot. It might be the fuel pump, which I read you have to get 2, or it mught be the fuel relay pump and I would like to know where the relay pump would be located. We looked, but couldn't tell which one it was. It died at my Grandmother's house and he had the mechanic look at it to see if it was the fuel filter. We were hoping it was, but the filter is practically new. Anyway we had my Grandmother's car and took it back over there to see if we could find the fuel pump relay. No luck, but my dad started the car and it started right up. We made it home and then he tried to start it again and no luck. Maybe it will start agin when the engine's cold. Hope someone can help here. Thanks.