Hi All,

I have this idea to upgrade the fuel pump system on a 75 164e to a pre pump type as used on the 78 and newer 240 cars. The car has long standing issues with hot start, vapor lock and poor running with low fuel level. I tried a differnt main pump with no symptom relief. Thinking Volvo had a good idea with the pre-pump, especially the higher output version on the B230 cars to assist that main pump, which costs a lot to replace BTW, I can fix the symptoms of a bad pump by upgrading.

The issues I see are:
tank to main pump outlet location, on tank for 164, in sender on 240
main pump location, on tank vs on body
fuel filter location
fuel guage calibration 10 volt stabilizer vs 12 volt, and different resistance on senders as well
tank venting, very different on newer cars.

solutions:
Use tank, sender, pre-pump, main pump and fuel filter bracket from a newer 240 car.
Only issue not solved is the venting, I am having a bit of visualizatioin problmes with it. Perhaps a 78 or 79 car has the same venting, but different feed??

Anything else to add?

Thanks,
Tom Durkin
Portland, OR

Well, I have determined the different venting methods is the stumbling block for this upgrade/ modification. The newer cars use the cap for the venting, both overpressure and vacuum. The problem is the filler necks mount different. So for the time being, I have reinstalled the tank and the car is back on the road.

I flushed the injectors with 3 volts opening the solenoids. lots of gunk coming out, I hope this may help the hot starts issues.

Thanks for all the comments.

Tom

Maybe I was just lucky, but all the time I drove my 75 164 I never experienced what you describe. I thought the single pump setup was great as I never had a problem. I have a 82 245 and I had to replace the prepump after 8 years. I am not sold on the two pump setup. IMHO you have some other problem that you need to find. I did have to take out a needle valve on the outlet side of the pump when It became stuck shut off the gas to the injectors. I just left it out and car ran fine for years.

I have thought of this very solution to problems I've had with the 122E. My concern is the volume the pre-pump pumps (get that?). Would you have to have an overflow for the pre pump, too? Also, will the prepump fit into the tank? I know the 122 tank is too shallow, but haven;t ever looked at a 160 tank.

Why wasn't venting already necessary? I thought all tanks had to be vented. Just wondering. I need to add a vent to mine and run a line to a charcoal canister or something. I'm currently having the leaks fixed that served as vents before.

Demonic Tronic. That's too funny.
--
Justin 70 1800E, 66 122E

Another old time solution to vapor lock was wooden clothes pins on the metal gas lines. The wood absorbs heat - safely, and also creates turbulance around the line.

Good luck

Kent
1972 -164E
1955 - T-Bird
1968 -1800S
In order of priority

Clothes pins, I like it.

I have the tank out already, looked in for more debris but is clean.

will do more research on the venting systems, new vs old.

Tom

Before you go to all the trouble, it may be best to check the rest pressure on your D-Jetronic system. The hot start and vapour lock conditions can be caused by a ruptured fuel pressure regulator diaphram, which does not leak enough to show up on a running test, but will show up when the pump is off on a hot shut-down. Some mechanics in the 80's actually drilled small holes intentionally in the diaphram in an attempt to solve the hot start problems, which of course ruined the regualtors.
Fuel pump check valves can also fail.
They don't call it Demonic Tronic for nuthin'.

Rest Pressure stays at 20 psi for over 45 minutes.

The fuel filter placed above the pump is an issue for me as well, removed the pump outlet hose to discover debris on the check valve. This gravity drain back makes me want to relocated the filter to level or lower than pump location.

Tom