W126 - Normal hissing or tank purge issue? - Page 2 - PeachParts Mercedes-Benz Forum

tinypanzer · #16 01-19-2010, 08:39 PM

Gentlemen,

Thanks so much for taking the time to post this picture and give some explanation. This should make my troubleshooting much easier. The reason I am convinced something is awry is because I have never had such an issue with my 300SE.

What an interesting contraption that splash bowl is. I love how it is designed to use the return fuel flow to create a jet that draws in fuel surrounding the bowl to aid in low fuel reliability. How neat.

Thanks again!

hookedon210s · #17 01-19-2010, 09:32 PM

Good luck finding the problem and let us know what you find. Mark

hookedon210s · #18 01-19-2010, 09:54 PM

One more thing: I don't know if you have owned your car for long or know its history but it seems this type of problem with 126 vehicles comes from sitting for months or years with partially filled fuel tanks which permits water vapor to accumulate and condense in the fuel tank. This leads to rusting of the inside of the tank and varnish/coke deposits. This can cause a multitude of problems and led to a now ventless fuel tank in my 1983 380SE and the problem referenced in post #6 found here. Mark

560SEL Doesn't Hold Idle,Sometimes It Idles Roughly But Stalls As Soon As I Tap Gas !

tinypanzer · #19 01-20-2010, 10:49 PM

You hit the nail on the head - I haven't owned the car very long and it definitely sat for quite a while. My indie showed me the "gas" that he drained out of the tank. It looked like vinaigrette that hadn't been shaken...... He put a new fuel filter in.

As advised, I've run several tanks of gas through it with a bottle of Techron in each. He told me to overdose it the first few tanks just to get all the old crud out of there.

I am starting to notice a bit of an intermittent miss at idle, and I wonder if there is any correlation as noted in that post you linked for me.

Man, where to start?

hookedon210s · #20 01-21-2010, 06:29 AM

Quote:

I am starting to notice a bit of an intermittent miss at idle, and I wonder if there is any correlation as noted in that post you linked for me.

Man, where to start?

I don't know what basic maintenance you have performed to date but always start with the easy stuff first like checking for vacuum leaks, replacing plugs, checking rotor, cap and wires, etc. My rusty tank issue was probably an anomaly. Mark

tinypanzer · #21 01-21-2010, 03:48 PM

Good advice, but I've already taken care of all that stuff. This motor just had an overhaul including ignition components, air plenum, injector cups and seals, timing chain, guides, etc......

Something else is going on.......

hookedon210s · #22 01-21-2010, 05:23 PM

Then I would start by looking for vacuum leaks. Mark

MDE3 · #23 01-25-2010, 05:42 PM

I have a 16V that is having fuel leakage problems out the fill cap..have replaced the cap with new so it is not a cap issue and seems to come down to over pressure inside the tank forcing fuel out of same. Does anyone know if the 16V tanks have the same arrangements as described above? This car did sit outside for a year while awaiting an engine transplant..and did have old fuel in the tank

I was wondering if spraying or squirting Techron up the vent pipe from the outside of the tank, followed by a blast of compressed air might serve to clean out the accumulated garbage. We have replaced the vent valve, purge valve (at the front under the hood) carbon cannister, most vent lines, fuel pump and screen, and pressure tested and smoke tested the tank outside the vehicle (tank removed)..Have run the car with an open elbow instead of the vent valve..which helped the situation, but was not a complete solution..had cabin fumes all the time...fuel system leaked at several places...which are all fixed now..except for leakage around the fill cap.