[cookie79]

I am a new member who has recently purchased a 1979 450SL. I purchased the car approximately 200 miles from my home. 150 miles on the trip home the car died while I was traveling at 70 MPH. After pulling to the side of the road I tried to start the car. It would turn over but not start. I continued doing this over a period of thirty mintes. Each time the engine came closer to turning over and starting. At the time the tow truck arrived the engine turned over and started.
The next day the car started and is running smoothly, but I have no confidence in driving this vehicle for an extended time.

My questions are:

Has anyone else experienced such a problem?
How was it solved?
Could this be a vapor lock problem?
If it is a vapor lock problem, what is the cure?

Looking forward to reading your opinions.

Thanks,

Cookie 79

 

[Digmenow]

Cookie, this happened to me last summer as I was crossing the Wilson bridge from Maryland to Virginia. I had the car rollbacked to my indie's shop and of course, it started right up. Claude thought it was the fuel relay, located up behind the glove box. He removed the two clips (screws?) that hold the glove box in place and replaced the relay. $200 later, I was down the road and have never experienced the problem again (fingers crossed). Hope this helps.


BTW...when it's running, do you hear a buzzing or loud humming coming from the rear of the car?

 

[ussun]

I had that happen to when I bot mine but it was raining and..... Just before my friend showed up it started. Never happened again. I told my indy mach and he said when it totally fails he'll find it but it never did. Welcome to the world of SL but keep driven it they love that and post some pics

 

[C230Kto380SL]

Hey Cookie,

& welcome ..

Each time the engine came closer to turning over and starting. At the time the tow truck arrived the engine turned over and started.

Looks like your first maintenance job will be the fuel system.

Get the tank drained, I'll bet there's a lot of sludge in the bottom of that sucker, change your fuel filter and have the fuel pump and the rubber hoses down there inspected while you're at it. any leaks in this area will starve the engine of fuel even if the tank is near half full - that was my experience.

 

[mbslns]

To answer your question on vapor lock, fuel injected cars typically do not suffer vapor lock because of the higher fuel pressures. Fuel is applied via pressure at the injector instead of by vacuum at the carb venturi.

 

[daryn]

Fuel injected cars can indeed get vapor lock as did my mom's del sol. If the gas in the fuel lines evaporates you get vapor lock, boo! You gotta let the car cool down and try again. I heard someone in the desert say something about insulated fuel lines but because this problem has never afflicted me(knock on wood) I cannot offer much advice.

 

[mbslns]

I don't know about my mom's car, since it's been 30 years since I've driven hers, but fuel pumps in an injection system push fuel (cool) from the tank past the injectors and return it to the tank. No place for vapor to stop in the system except for the short line from fuel rail to the injector and that should be pushed out in a couple of cycles while cranking.

 

[cookie79]

Dig,

Thanks for the reply. I'll give that a shot. I did take the car out this past week for a 60 mile test run. No problems. Maybe next weekend a 90 mile trip. As to the BTW question I do not hear any humming or buzzing from the rear. If I did what, would that mean?

 

[cookie79]

Took it on a 120 mile round trip ride. No problems. Would that mean that the fuel lines are not the problem?

 

[Digmenow]

Dig,
As to the BTW question I do not hear any humming or buzzing from the rear. If I did what, would that mean?

A loud buzzing coming from the rear of the car is an indication that the fuel pump's days are numbered. Louder equals worse. Sounds like you're ok.

 

[cookie79]

Cookie79 1979 450 SL photo

I had that happen to when I bot mine but it was raining and..... Just before my friend showed up it started. Never happened again. I told my indy mach and he said when it totally fails he'll find it but it never did. Welcome to the world of SL but keep driven it they love that and post some pics

This is the newly purchased 1979 450 SL.