Car is a 1988 with the 63L tank. I tried a couple shortcuts to fix my fuel starvation issue, a new filter, a new pump, etc… but nothing worked. I finally put on my big boy pants and spent the time and money it needed to get it done. My car was sputtering on 1/2 tank, so I assumed it was a bit worse than most. Here are the steps I did:
-
Drain and remove fuel tank. The fuel was “cloudy” while draining so I knew that wasn’t good. After removal, I opened every hole in the tank and removed every hose. I let it sit outside in the sun for a couple days to fully vent and dry. The cloudiness was from the form of oxidization that happens in a tank. It had a powdery feel inside the tank.
-
Pour 8 gallons of Apple Cider Vinegar into the tank. (yes, the same you buy at the grocery store). Not the clear stuff, but the brown. Its an old hot-rodders trick. Tape up all the holes and swish it around as best you can. I even drove around with it in my truck for a day to help clean it. When I poured it out, it was nasty dirty.
-
Rinse the tank with lots of water in every direction you can until its all clear. Let that drain for about 1/2 hour.
-
Dump a gallon of acetone in the tank and swish around. Dump it out. Tank will be dry in a minute or two. After all the above, the tank was incredibly clean inside. I made sure it had vented and then taped up all the holes so no debris would find its way in as I worked on it.
-
Using your favorite vendor (I used Pelican Parts) replace all the lines that supply the system. All the curly-Q ones etc… I kept the old ones for my track spares if ever needed. Buy a couple fuel filters. One for the car, one as a spare.
-
I then did the 2 pump conversion. The low pressure pump that goes in the drivers side of the tank comes out of damn near anything pre 1988. (I used Pelican part number 16141179415M9). I plugged its return side line with a small length of hose with a tight fitting bolt and a couple hose clamps. Its pump side now feeds the return port of my primary pump. After removing the original sender from the drivers side, I used a sharp pair of tin snips to remove 1/16th of material from one of the lugs on the tank to allow the pump to fit in. Others have filed that notch. The primary pump I used was Pelican number 16141180233M82 It has 2 tubes. One gets fed from your newly installed low pressure pump. The other feeds the car.
-
Wiring was “simple.” The right side prong wire on your existing pump gets spliced and goes to the right side prong on the additional pump. Same holds true for the left. I went to Radio Shack and found some small connectors that worked on the new pump. At some point I would like a BMW pigtail to wire in instead.
This conversion took approx. $600.00 as I purchased all new pumps and fuel lines. Not counting drying or cleaning time on the tank, plan on spending approx. 6 hours of labor time doing it.
I am only currently running the original sender from my passenger side pump, meaning my fuel gauge is not accurate. That’ll be a winter project.
When all was said and done, I added 5 gallons to the empty system and ran on track for 25 minutes with no issues. Before the conversion it sputtered with 8 gallons. The track I run is primarily right turns. This was a major improvement.
I combed a ton of forums here and on e30tech and R3Vlimited to learn about this. A big thanks to jlevie, ranger, and cwbaader as at some point I’ve put their knowledge to work on my car through things they have posted.