SDL fuel issues..........the trip from hell........ - Page 2 - PeachParts Mercedes-Benz Forum

auspumpen · #16 06-07-2009, 12:35 PM

Has anyone installed an aux. electric lift pump that can be used after a filter change or in an emergency like this? I'm thinking of one that allows fuel to flow through unrestricted when it's not running, but will kick in for some additional ummph when needed--like the little Facet pumps. The 60x engines seem to be prone to fuel starvation issues that can take a while to resolve once air is introduced to the system.

pawoSD · #17 06-07-2009, 03:29 PM

From my calculations the 617 passes about 1/3-1/2 gallon per minute of extra fuel at idle through the return line.....more if at higher rpms.....I checked this by putting the return line into a bottle for a bit when running my engine.....

I'd assume a 603 should move about the same? Perhaps check the amount of fuel it is circulating and if it is minimal its probably a real weak lift pump.

Hit Man X · #18 06-07-2009, 04:21 PM

Well to non-603 guys, the IP self bleeds so all I can think of is the lift pump at this point in time. Is this the '87 or one of the '86s? Perhaps the cat is overheating under the car?

And lol @ the $4700 fuel tank, you can get aftermarket tanks that hold more fuel and that are made of plastic for maybe $1k.

Brian Carlton · #19 06-07-2009, 08:36 PM

Quote:

Originally Posted by Hit Man X

Well to non-603 guys, the IP self bleeds so all I can think of is the lift pump at this point in time. Is this the '87 or one of the '86s? Perhaps the cat is overheating under the car?

It's the '86........no cat. But, it's a fuel issue.........nothing else is possible.

I don't see how it can be anything other than the lift pump or the tank strainer............and the sudden onset without any prior symptoms tends to eliminate the strainer.

Hatterasguy · #20 06-07-2009, 08:41 PM

I forget, how do the fuel pumps on these cars work? Diaphragm? Impeller?

probear · #21 06-07-2009, 08:50 PM

Quote:

Originally Posted by Brian Carlton

It's the '86........no cat. But, it's a fuel issue.........nothing else is possible.

I don't see how it can be anything other than the lift pump or the tank strainer............and the sudden onset without any prior symptoms tends to eliminate the strainer.

Simple test. Just take a small container of good diesel and connect under the hood at the tank lead in. You might want to save a portion of the fuel if you need to pursue the 'bad fuel' route with the oil company.

jcciem · #22 06-07-2009, 08:57 PM

I thought the '86 and '87 were identical, both had the trap oxidizer. When factory recall was complete the trap oxidizer was removed and a catalytic converter was installed underneath. I had the same symptoms in February, ran nice cold, but the warmer the engine and exhaust system the slower it crawled. Eventually I had a no start condition, somebody here directed me to the test bolt in the exhaust manifold, removed it, the car ran fine put it back in no start or run. Replaced the catalytic converter, runs nice since. If the '86 and '87 are not identical, disregard everything above.

'87 300SDL 260,000
'94 SL500 49,000

Hatterasguy · #23 06-07-2009, 09:04 PM

I wonder if its water? Brian did you pour the filter into something clear? I wonder what the fuel looks like?

When I had water problems with the VW and SD they acted similer. Ran like crap until you let them sit a bit. Than the water would settle and the filter would flow well for a bit.

Before throwing parts at it, I wouldn't rule out a bad load of fuel. Those little stations can be hit and miss.

Fulcrum525 · #24 06-07-2009, 09:08 PM

I was about to say..... as far as I can tell no station on the Merit sells diesel.... I always make a point to ensure that I have 1/4 of a tank before i'm on it.

Look at the bright side, at least it happened on a Saturday and not while you were on one of your business trips.

Hit Man X · #25 06-07-2009, 09:20 PM

Quote:

Originally Posted by jcciem

I thought the '86 and '87 were identical, both had the trap oxidizer. When factory recall was complete the trap oxidizer was removed and a catalytic converter was installed underneath. I had the same symptoms in February, ran nice cold, but the warmer the engine and exhaust system the slower it crawled. Eventually I had a no start condition, somebody here directed me to the test bolt in the exhaust manifold, removed it, the car ran fine put it back in no start or run. Replaced the catalytic converter, runs nice since. If the '86 and '87 are not identical, disregard everything above.

'87 300SDL 260,000
'94 SL500 49,000

'86 Federal had no Trap and no cat, '87 did either way.

Brian Carlton · #26 06-09-2009, 01:06 AM

Quote:

Originally Posted by Palangi

When my 240D was acting like that, it ended up being the lift pump. Lift pump rebuild kit by a Bosch shop fixed it. Problem was caused by rust flakes. A surprising amount of krap can get by the prefilter over 20 years time.

I believe the prize will go to PP.

Tested the pump today. The spec is 5 oz. in 30 seconds as measured via the return line (thorough the secondary). Due to plumbing problems, I decided to test the output of the pump directly without the limitations of the secondary.

After 30 seconds, I found exactly 2 ounces in the glass jar.

So, the vehicle would run under very low power conditions..........but, any real demand and the engine would lose all fuel.

I also found the secondary to be not quite full...........yet again.

Parts ordered.

kerry · #27 06-09-2009, 08:29 AM

Does there have to be an air leak in order for the secondary to be less than full or is the IP pulling a vacuum in the secondary?

awsrock · #28 06-09-2009, 08:43 AM

My secondary is only half full as of late, while the engine is running. When off, it will fill up and only have the small bubble sitting at the top. I think it might be the cause of my somewhat rough idle..(new motor mounts in the winter, as well as injectors..)

Anyway, I bypassed the fuel thermostat for the summer, since I could tell that it was leaking a little bit, and that did not help the idle conditions very much, if at all. Power for me seems fine, although the difference between 3/4 throttle and full is pretty hard to tell. This could be from torque converter slip, or perhaps we have a similar problem?

I'll be keeping an eye on this thread to see what you come up with; at the same time, if I happen to figure it out first, I'll let you know!

kerry · #29 06-09-2009, 08:59 AM

Quote:

Originally Posted by awsrock

My secondary is only half full as of late, while the engine is running. When off, it will fill up and only have the small bubble sitting at the top. I think it might be the cause of my somewhat rough idle..(new motor mounts in the winter, as well as injectors..)

Are you sure you're not referring to the primary? How can you see inside the secondary while the engine is running?