Hi Everyone,
I just purchased a 1972 280 SEL with 4.5L V8 from a woman this past week. The car has been sitting in a garage for the 19 years, unmoved! Today, I did the usual to try to get it to start. I siphoned out the old fuel and put in new 93 octane gas, put in new oil, put in a new battery, changed out the spark plugs. The engine would crank over, but wouldn't start. When putting starter fluid into the intake, the engine would start for about a second, but never fully start or idle. I'm thinking that there is a fuel delivery issue. When I turn the key to the first position, I don't hear the fuel pump kick on, and the gas that I siphoned out of the tank (19 yo gas) was red! Also, the fuel gauge is stuck on E, even though I put 5 gals in the tank. So I'm thinking the problem is:
1) Fuel screen in gas tank is clogged by debris
2) Fuel pump is dead
3) Fuel pump fuse or relay needs to be replaced
4) Fuel injectors are clogged
5) Fuel filter is clogged

I'm still waiting for my service manual in the mail. So, in the meantime, anything else I might want to think of?
Thanks,

1) probably true.
2) probably true
3) Check that power is going to the fuel pump using a test light before writing off the relay. Fuel brakes down into varnish and will seize a pump.
4) Check 1,2 first
5) Replace it regardless


You'll need to drain the tank and not syphon it. The drain tan k is right at the bottom of the tank. Fuel breaks down into water and varnish mix. The red that you see is rust. The rust will build up and clog the strainer so remove it, drain the tank and then replace and put new gas.

If the pump does not move, then it's probably dead from sitting gas. Start there.

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With best regards

Al

Agreed with Al's responses.

I am doing the same with a 71 300sel 3.5 that was garaged for 30 years in Brooklyn.

If you need a fuel pump i was able to purchase a new for $228 which is cheap. Send me an email at kmukherjee10@hotmail.com and i can send the info.

Remove the pump from the car. If you do and gas comes out of the line for the inlet to the pump, drain the tank out and then you should remove the plug to get the rest out.
Carefully try to clean the pump, if you think you won't be able to then have someone locally in a mechanic's shop clean it for you... You may not need to replace it, they are pretty durable especially when all they did was sit.

FWIW the wire to the pump relay itself may be bad - the seperate thinner wire that connects to the (+) terminal on the battery. Make sure it's making good connection.

If you can verify the pump and you replace the filter, and verify you have 30PSI at the fuel rails under the hood, then you need to clean the injectors. Make 100% sure you replace all the under-hood fuel hoses with EFI hose ASAP, or you will cause a catastrophic engine fire as 30PSI of fuel spurts everywhere.

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

Those pumps can be cleaned with brake cleaner. They come apart into three parts with two seals. You will either need to replace the seals or wait for the to dry out as they will swell from brake or carb cleaner.

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With best regards

Al

I would bet that you have rust in the tank, unless it was completely full while it sat. So, recommend that you pull the tank and have it boiled and coated (or replace it), or you'll be looking at clogging problems very soon after you get it running.

Good luck with the car!

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Stabil, is curative, as well as preventative.If you have some time, I would do as these guys say, but I have found that if you add an excessive amount of Stabil to a system, it melts the varnish/crud, and gets things flowing again.
I had a Jeep,CJ5, that I bought, and facing downhill, in my driveway, it would not get fuel.I replaced the pump, took off the fuel line, at the pump, and no flow.
I went to a long term auto parts store,that the owner drives a 53 Chevy, and asked what to do.He said put in a quart of Stabil, and let it sit for a while.
I did, and left the fuel line off , at the pump.After a day or so, it began to drip, and in a couple of days, it broke loose, and ran the tank out.
The problem you have, is that it is hard to get the stabil circulated into the pump.
I bought a 380SEL, that had sat for around 15 to 18 years, and wound up replacing the pump, to get it going.
A word of caution, and something I never would have dreamed of = The 380 sucked the transmission filter into the transmission, and messed up the transmission.
I would change ALL the filters, and especially the transmission filter, and fluid, before attempting to drive.
I would then run a considerable amount of Stabil, for quite a while after you get it running. (Several tank fulls)
I realize not everyone is going to think the Stabil works, but I am positive on this.Whatever keeps the varnish from forming ,(preventative), works on varnish that has already occured,(curative).It will greatly clean up your system.Good luck! Mark

So, here is an update on what has happened so far. I finally decided to just have the car towed to a pretty reputable mechanic that specializes in vintage Mercedes. He has gone through a thorough (but extremely slow) process to get the car running so far. First, he replaced the fuel pump, and now the car is running, but misfiring and has a really rough idle. Next, he is going to check out the points and trigger points. Also, now that the car is running, he tells me the transmission doesn't work. When he puts it in gear, it gives a slight hesitation, and then nothing. Its been almost 3 weeks, and that's all he's come up with so far. I'm getting kind of antsy and this guys seems to be in no hurry to get any of this done. I'm starting to wonder how much of this stuff I can do myself. Should I bring this thing home or is it to complicated to do on my own?

You'll find out quickly (if you haven't already) that it will cost you a small mint to get this car running and drivable and in a roadworthy, reliable condition if you have people work on it for you. If you're mechanically inclined, you can do all that stuff yourself easily. I bet the transmission is just in dire need of a good top-off (if not a good flush, filter change, and then top off).

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

first thing do a search on here and you will find the answers you need about your probs with the car.such as rough idle. prob a vacuum leak or oily trigger points. etc. if you have some mechanical abilities and tools and a manual you can prob do it yourself.or just give up and give it to me!

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1972 280 sel 4.5
1986 xr4ti
For any given large, complex, hard-to-understand, expensive problem, there exists at least one short, simple, easy, cheap wrong answer.

In my opinion, the car is in general too complicated for someone with little mechanical and/or MB experience to do more than basic service on. You're basically trying to revive a patient that's been in a coma for decades. Not a job for a 1st year med student. Let the guy get it going, and if he's a good guy maybe he'll tell you what jobs he thinks you can do and what he thinks he should do. You're going to get to know him (or another mechanic of your choice) pretty well before you're done.

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1987 W201 190D

To clarify my post... I think you can learn a lot as you go, and you'll get to the point where you CAN do a lot of this yourself. But I don't think it is wise to start until the car is at a decent baseline condition, or you have a lot of guidance from someone with a lot of experience.

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1987 W201 190D

If you "get" the basics of the system, there's no reason that you can't do the remaining troubleshooting and rehab. It's not rocket science and there are plenty of posts from guys who have resuscitated D-Jet cars.

You need to invest in the basics like a Mityvac, fuel pressure gauge, engine stethescope, multimeter, and timing light. I highly recommend a low-end CO tester (like Gastester), plus a decent set of hand tools.

But if the trans is trashed, it may not be worth going any further with the car.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

So, I finally decided to bring the car home after three weeks at the shop and hardly anything done. I just now started the car, has a very rough idle, needs constant gas in order to avoid stalling. If I push the pedal to the floor, the rpms go up for about 3 seconds, then you hear a popping coming from the air intake cover (where the holes are), and the car begins to stall again. Not sure if the air temp sensor at the air intake works and there is a rust hole in the lid of the air intake, which is probably a big vacuum leak. Is it solely a sensor issue, or idle speed, or electrical, or vacuum issue?
Next, I actually tried driving the car on my street, the transmission does work, but there is a major power issue, the car starts to struggle past 10 mph or when going up hills, especially struggles in reverse. Seems like there is major resistance going in reverse.
Third, the brakes have major issues, the pedal will hardly budge with even the toughest force, and takes some serious distance to stop the car even from 5 mph and in neutral, even longer if i leave it in drive. Possibly the brake unit or just need to bleed the system?
Seems like the power steering works good, so that is a plus. I'm waiting for wireset, gaskets and trans filter in the mail, going to flush the trans as soon as i get it, going to do oil change tomorrow. Appreciate all your help, guys!

Major vacuum leak will cause some of those symptoms if not all.