Fuel smell? Will my car catch on fire?

[JeffreyNMemphis]

Hello Friends,

My 1973 280SEL 4.5 had a very noticeable fuel smell. The mechanic that works on my Porsche thought the car might be running very rich, but he doesn't work on the old Mercedes so he couldn't help. A shop that I found took it in and said the injectors are leaking and that I should replace all eight (0 280 150 36) at $200.00 each plus seals ($1700.00 plus labor). Ouch!

I took the car back and decided to try and DIY. I found two new injectors for $160 each from a garage I know (He was happy to get cost for them). The valve covers are leaking, so it is hard to tell if the grime around the injectors is derived from oil or gasoline. I sprayed carb cleaner around the injectors and used the air compressor and a tooth brush to get it clean and dry. I figure this way, if there is something leaking it should look like fresh oil or gas and I can say for sure which one or both.

While I had the air cleaner off, I looked at the cold start valve. Two of the three hoses connected had cracks, the other was loose. Could leaking hoses from the cold start valve be the source of gas fumes?

I replaced the two cracked hoses and tightened the other one.. The fuel injectors are clean and dry, will check them again tomorrow for evidence of leaking. Hopefully, I won't have to replace the injectors.

[t walgamuth]

Yes. And replacing them could have saved your car from a fiery death!

If the car runs well, I would not replace any injectors.

YOu should be able to tell raw gas smell from unburned gas smell coming from the exhaust. One is a fire hazard (your leaky hoses), the other will simply cause poor performance and perhaps waste gas and foul your plugs.

Tom W

[GaryF]

Get a length of fuel hose and some clips and replace all the rubber parts of the fuel rail under the hood. Also if the injectors have the original short fuel hoses that are crimped on they are probably leaking so either get the replacement kit or make your own from short lengths of hose. While you have the injectors our also replace the rubber seals. There's lots of info on this board about it.
The whole job wont take more than a few hours or cost very much.

[Tomguy]

The injector hose on this car has fuel at 30PSI. A burst hose could (and has many a time) mean the death of a 3.5 or 4.5.

Replace all the rubber lines, including ones from the rails to the injectors. Injectors rarely need replacement, unless they're cracked and leaking from the body, rusted from non-use, or damaged from impact. Use EFI hose - NOT fuel hose - for this, it's meant for more pressure. The gas smell will go away.

[pxland]

I would also check the return line coming off of the back of the fuel rail. It may look okay, but when I squeezed mine it seeped fuel.

[JeffreyNMemphis]

Hello Friends,

Thank you all for the replies...

I drove the car 75 miles today after changing the hoses, no fuel smell at all under the hood, no evidence of fuel leaking from the injectors either. I plan on replacing all of the rubber hoses in the very near future.

[meltedpanda]

one of the first things I did on my 450, replaced ALL the rubber I could get to, cheap insurance.....

[Mark DiSilvestro]

And when replacing the fuel-injection hoses (with fuel-injection hose) be sure to use fuel-injection hose-clamps, either the original factory clamps or new ones. The typical autoparts store worm-type hose-clamps may cut the new hoses.

Happy Motoring, Mark