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I've got a 72 1800ES with fuel problems. My mechanic thinks it might be a corroded pick up line in the tank but we recently replaced the fuel sending unit and the tank is nearly spotless, including the brass filter at the bottom so I don't think that's the cause.

The car runs perfectly on a full tank until I use about 15-20 litres (4-5 gallons) of gas, then it runs like air is getting in the system or as though only pulses of fuel are getting to the injectors. The more I try to run it with less than 2/3 of a tank, the worse it runs. This happens with every tank of gas for the last year.

The only exception to this rule occurs when I have a full tank of gas but the engine is very hot. For example, I recently drove about 100 km (60 miles) out of town and filled up before I left. The car ran perfectly for the first 45 minutes then started hesitating intermittently. It's like the fuel supply goes off for a second, on for a second, but surprisingly the car almost never stalls. In this case, I pulled over and let the car cool down for 10 minutes and it ran perfectly the rest of the way.

To summarize - the car runs like crap with less than 2/3 of a tank or when it is very hot. Any suggestions?
 

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Hi Bolnobolus, Sorry I have no possible explanation/ solution, but thought this might be a good place to throw out my issue too. I also have a '72 ES that has not run in 18yrs. I replaced spark plugs, oil, fuel, fuel filter, battery and it will turn over. A well regarded Volvo mechanic and restorer inspected the whole car and said it needed a fuel pump replacement and would likely start. I pulled the fuel pump and it was full of gas and it would spill from both ends. Does anyone know if this would be evidence that the pump is fine (as well as the fuel tank and lines at least up to the pump)? If so, am I at the replace the fuel line stage (I couldn't smell or see and gas when I pulled the fuel rail before the injectors.
 

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I would also consider plug wires, cap, rotor, and points is it has not run in years. With the fuel pump, I would connect the line in from the tank and then crank the car to see if it is pumping fuel out to the engine. Have a way to collect the fuel that comes out. If it has sat for 18 years I would drain all the fuel from the lines and tank and put in fresh fuel. The carburetor is likely to need rebuilt as well.
 

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It is fuel injected, so how does that change things? I am wondering if the lines might be plugged? Should the output from pump look like a dribble, or a steady stream, or should it have some strong force behind it? As I said, I got no indication that fuel is getting to the rail on the engine, so i hadn't gotten to the ignition part yet, but that will definitely be in my mind if I get the fuel up that far ( I am guessing it the pump is working and the lines are clear, the fuel should come squirting out the rails?).

BTW I have the car on Craigslist for $2K to see what happens, but will continue to tinker and see if I can get it working better with relatively little cost.

Thanks
 

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It would be a steady flow. If you can confirm that then you know you have fuel to that point and can tackle from there. With it being FI you would contend with the injectors. You may want to see what you can do to clean them.

Hope this helps.
 

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Human nature is to expect the worst...

I'll explain my solution to a similar problem.

My '73 ES has suffered from lack of use over the years. In storage for 3 years sorting out a divorce, busy work schedule, crappy roads that limit my diving enjoyment. 2 years ago my 1800 started to mysteriously stumble, hesitate, no power, etc. It would however come around after sitting for a while and run normally for a bit. I would also hear the fuel pump running noisily when this occurred.

First step was to change the fuel filter. No effect. Then bought a fuel pressure guage. Drove around with the stupid thing poking out from the back of the hood for a while and then it finally happened again. Fuel pressure dropped when the car ran poorly. Bought new Bosch fuel pump, and filter. No effect. Damn. Had a friend's shop drain the tank and they they suggested cleaning the strainer and using fuel system cleaner since there was crud in the bottom of the drain plug. No effect. Drained tank again, still lotsa crud. Found it was worse when driving 'vigourously'. New strainer and filter (again) more cleaner. No effect. Removed fuel sender and found corrosion on upper half. Ran my fingers inside the top of tank and found more crud. Fit new fuel tank.

Problem solved.

I always stored the car with the tank filled, used fuel additives, and kept an eye on things. The tank looked clean and shiny through the sender hole but every time we removed the lower drain plug, there was dark brown residue. This was stirred up with acceleration or cornering and plugged the strainer. When the car was shut down, the crud fell off the strainer and it ran OK for a while. Since the tank is baffled, cleaning was not really an option so I bought a new, replacement tank.

Persistance and money will fix anything.

Volvo 1800ES pictures from classic cars photos on webshots
 

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I'll explain my solution to a similar problem.

My '73 ES has suffered from lack of use over the years. In storage for 3 years sorting out a divorce, busy work schedule, crappy roads that limit my diving enjoyment. 2 years ago my 1800 started to mysteriously stumble, hesitate, no power, etc. It would however come around after sitting for a while and run normally for a bit. I would also hear the fuel pump running noisily when this occurred.

First step was to change the fuel filter. No effect. Then bought a fuel pressure guage. Drove around with the stupid thing poking out from the back of the hood for a while and then it finally happened again. Fuel pressure dropped when the car ran poorly. Bought new Bosch fuel pump, and filter. No effect. Damn. Had a friend's shop drain the tank and they they suggested cleaning the strainer and using fuel system cleaner since there was crud in the bottom of the drain plug. No effect. Drained tank again, still lotsa crud. Found it was worse when driving 'vigourously'. New strainer and filter (again) more cleaner. No effect. Removed fuel sender and found corrosion on upper half. Ran my fingers inside the top of tank and found more crud. Fit new fuel tank.

Problem solved.

I always stored the car with the tank filled, used fuel additives, and kept an eye on things. The tank looked clean and shiny through the sender hole but every time we removed the lower drain plug, there was dark brown residue. This was stirred up with acceleration or cornering and plugged the strainer. When the car was shut down, the crud fell off the strainer and it ran OK for a while. Since the tank is baffled, cleaning was not really an option so I bought a new, replacement tank.

Persistance and money will fix anything.

Volvo 1800ES pictures from classic cars photos on webshots
BHart

What did the new fuel tank cost? The reason I ask is we have a place here in Oregon, Oregon Retinners. http://www.retinners.com/. We have had many fuel tanks that are not available any more, or the repop tanks wont fit correctly and have used them to restore the original tank. They do a great job.

I know its a little late, but some good info to write on the wall for the next time.
 

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The tank was new from VP Autoparts and was $500+USD.

It fit well, had all the internal baffles, the mounting holes lined up, external fittings all there but there was no provision for an in-tank strainer. Made something up myself (not concours :mad: but there you go)
 
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