Hey everybody,

So yesterday I ran my 280 out of gas.. After rectifying that situation with not too much strife, I thought it was behind me. Next time I started up, it doesn't want to stay engaged. I give it gas, and it flutters and will stall unless I continue gassing it in neutral. I floored it over the Pulaski Bridge and it belched some smoke and ran well the rest of my ride.

This morning, same flutter. My assumption: That 37 years of sludge in the tank is now passing through the engine, and clogging something up.

While I hope this will be cathartic for the car in the long run, I'm wondering if I've made some critical mistake here. Should I be looking into something more closely?

Am I a candidate for a sea-foam treatment?

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1973 280 - 90,000 miles

A real fuel filter would be a start, what passed for one forty years ago, that little screen door affair that I think it NLA, at the carb inlet isn't good enough.
I put in one of these http://www.summitracing.com/parts/FRM-HPG1/
It's physically larger than it looks, but is a fine piece.
There is also a strainer in the tank, fuel flows freely so I haven't bothered with mine yet.

If you have sucked some crud into the carb, best way to get it out is to pull the carb apart and clean it, but that is perilous. I'd bet money it will not work right when it goes back together if it's been working right and un-molested for any length of time. Try serious doses of seafoam or whatever you cleaner of choice is as you suggested.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Hey wolf, thanks much for the help. I've located an aftermarket fuel filter running between the carb and the engine. It's clear, so I can see the filter is indeed gunked up and rust colored.

So this I what I'll change. Question: do you know where the fuel pump relay is fir our car? Or is it a fuse? I read that this should be disconnected, and after having started the engine and bleeding it dry, it's then safe to disconnect the filter.

Is there another fuel filter in between the gas tAnk and the carb? In the manual it seems there is...

Thanks man!!

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1973 280 - 90,000 miles

Fuel pump is mechanical on our car, is mounted low on the drivers front side of the block.
Stock, there is a filter in the tank, under that big socket looking opening in the bottom center of the tank, the other is at the inlet to the carb, at the big screw fitting.
If there is an inline one it's an add-on and better than nothing, but I still observed crud in my carb while running one of them, hence the big orange fram one. For the inline one, I've got them from the filter rack near the oil filters at autozone, they are specifically for some older vehicle, but are a basic inline single in single out filter, just match up the hose sizes. I ran a clear plastic one once, it warped from underhood heat.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

The thing that puzzles me, is that this in-line is post-carb and pre-engine. I also took a picture of an apparatus that the fuel passes through directly before going through the pictured filter. The filter is filthy now that I see new ones online. I found a Fram filter that looks very similar to the one i've got, a G1, but I wish I could just walk into a store and buy one rather than getting one shipped to me.

I have read up on the filter that sits in the tank itself. Sounds daunting to me, like the tank would have to be empty to change that filter... right?

I am going to go to out to the car now and see if I can identify the pre-carb filter you speak of.

thanks always. and feel free to chime in everyone else!

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1973 280 - 90,000 miles

evoldeal,

I would recommend putting a can of Seafoam in the tank, this stuff works wonders. Any gunk that is clogged anywhere will get burned off once you run the engine with a little seafoam. It burns much hotter than gasoline thus it burns off that sludge that often is caked in the engine. Dont be alarmed if you see a little smoke coming from the tail pipe...this is normal.

Good luck,


-Curt

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'66 250S (SOLD)
'72 250C (SOLD)
'92 190E 2.3 (SOLD)
'02 C320 Wagon (SOLD)
'04 S40 (SOLD)
'99 535i (Euro Spec)

Evo, that filter's done its job, shouldn't be too hard to find an replacement. In BK I'd try Danken Auto Parts on 196 4th Ave.

Yes, pull that plastic filter off and go to a good parts store, preferably not one staffed solely but sullen teenagers if you know what I mean.

In your photo of the funky apparatus, that is the stock fuel bypass valve. The early one's had a vacuum source on the bottom, during high vacuum as in idle or cruise it opens the side port and sends excess fuel back to the tank. Under low vacuum, like hard acceleration, it closes and delivers all available fuel to the carb. The later version was much the same looking but had no vacuum port, it's a neat little valve that does the same thing but functions as a fuel pressure regulator also, 2psi or so I think it is, over that it opens the return line. It's a neat little gizmo, that later one.

Your add-on filter comes from the fuel pump on the motor heading to that bypass valve, which has one line going to the carb and one going to the return back to the tank.
If that makes sense.

Ditto the seafoam, good stuff. If your new filter, which might be worth trying to get a clear one for the first shot, get's orange and cruddy again quickly, it will be worth thinking about some tank draining if not cleaning and sealing. Hope not though.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Thanks brothas!

I went straight to danken this morning, got the Fram G1 (wolf, it is a clear filter), and installed it right there. I'd say I got a 75% improvment right off the bat! No stalling, no anemic idle. Still a little flutter when I give it gas, but hey I've always had that problem.

Thanks a million for working through this and save me from having to limp the car into the mechanics and explain. I will ask him about the mysterious second filter, which I guess IS in the carb inlet. Besides for the one in the tank itself.

I'll keep a close eye on performance and the filter itself. Feels great to hae the car running again.

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1973 280 - 90,000 miles

I wouldn't be surprised if the original one in the stock inlet neck of the carb is gone, or the screen rotted out of it. It's just a little plastic affair with screen mesh. I bought a NOS one off ebay awhile ago I think is in my carb now, just as an extra. They are NLA new I believe.

Glad it cleared up for you. If you don't have to take the carb apart, don't.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K