Fuel pump pressure

[mnahon]

I am helping a neighbour, Christian, to get his 1965 230SL back on the road. The car has been stored for about 15 years, and  Christian has finally decided the time has come to recommission the car. The car is in the Eastern Townships, about an hour out of Montreal. I visited it a couple of weeks ago and there's a lot of work to be done. Christian has hired a mechanic to do the work, who has a lot of experience working on cars (various, British, American), but not specific to Mercedes. He's already done a lot of reading on the Pagoda group and he's a full member. He's asked me to post some questions since he's more comfortable in French than in English.

The first question relates to the fuel system. It sounds like the car still has its early tall fuel pump, and the fuel tank may (or may not) have beeen changed to the larger tank. He's measuring only about 5 psi fuel pressure, though he's done a volume flow rate test and he seems to be getting sufficient flow rate (about 3 liter per min).

- is there a way to visually check whether the tank is 65 liters or 80 liters?
- did the early pumps have lower pressure than the later pumps, or were they all expected to produce 15 psi?
- how should the bypass be set up and could this affect the fuel pressure if it's not correctly set up?

We're essentially trying to figure out whether the low pressure being measured is normal; or maybe due to an incorrect setup; or indicative of the need to change the pump.

Thanks

[Vander]

If the spare tire is mounted vertically in the trunk, and not horizontal. I do not believe the 82 litre fuel tank would fit.

Has the fuel tank been removed and professionally cleaned? That is the very first thing I would do waking up a car from 15 years.

[mnahon]

Thanks Vander,

Yes, it is a vertically-mounted spare, so it would be great if I could get confirmation that that precludes the larger tank.

I'll double-check on what they've done to check/clean the tank.

Meyer

[Benz Dr.]

You can install the 82 liter tank in all but the vertical mounted spare 230SL's.

[mnahon]

Thanks Dan,

So that confirms the car probably still has its original fuel pump and fuel tank.

They've also confirmed that the tank has been cleaned and repaired as needed.

Meyer

[rwmastel]

Christian has hired a mechanic to do the work, who has a lot of experience working on cars (various, British, American), but not specific to Mercedes.

Is it difficult finding a mechanic in that area experienced with older Mercedes?

[mnahon]

I can vouch that it's quite hard to find anyone knowledgeable in older Mercedes around here. I do a lot of the smaller scale stuff on my car myself, and last time I needed larger scale work done, I drove the car to Dan Caron's, which is about 600 miles away.

[rwmastel]

Unfortunate that there's nobody available local.  Maybe that's a business opportunity for you or other mechanically experienced members here?!?

[ja17]

Try temporarily pinching closed the return fuel line from the injection pump to the tank. If the fuel pressure goes up past 15psi your by-pass could be the problem. If not check to see if your fuel pump has the screen in the intake fitting of the electric fuel pump. Clean it if so.

[Benz Dr.]

I can vouch that it's quite hard to find anyone knowledgeable in older Mercedes around here. I do a lot of the smaller scale stuff on my car myself, and last time I needed larger scale work done, I drove the car to Dan Caron's, which is about 600 miles away.

Sorry about the distance but we enjoyed having you over. Probably time for a visit, yes?

[mnahon]

Thanks for the tip Joe, I'll pass it on.

Dan, by all means, I've been thinking you should move closer. Kidding aside, you did such a great job last time, the car is still running great. The list of small things is starting to get longer though because I haven't had time to deal with them.

Rodd, my guess is that there may not be enough older Mercedes around here to warrant someone setting up shop here. I could be wrong. When I did a search for Pagoda group members in Quebec, which is a large area, I only came up with about 10.

[rwmastel]

Rodd, my guess is that there may not be enough older Mercedes around here to warrant someone setting up shop here. I could be wrong. When I did a search for Pagoda group members in Quebec, which is a large area, I only came up with about 10.

Time to get those 10 members out to some cars & coffee or other local shows to promote the Group!