Are you sure it's vapor lock? I was under the impression that the problem is more prevalent in the early FI e12's (70's 530i etc) because those in particular had cooling problems. Just never had it in my carb'd cars?
Vapor Lock/Electric Fuel Pump
- Thread starter Steven
- Start date
Michael, I should have kept the musical horns "Boys & Girls Together" "Hi-Low-Hi-long low" & "All as a Harmonic Haaaeeeuuuhhmmm"
Hey Peter, not sure if this was directed towards me but if it is, no I am not 100% sure. I thought I'd drive it more and see if it keeps happening. It hasn't but I am also not driving it when super hot out. One thing that has been bothering me is the car has a slight surge when driving at low speeds, like 30mph in third gear say, or when winding out 2nd a bit at sustained say 25mph. A lot of the speed limits are either 25mph or 35mph around town and it can be frustrating driving those speeds as the gears & motor don't seem to like driving at sustained low speeds.
It's kind of hard to explain, it is a very, very slight surge. Once I give gas and run it up to speed it runs fine, or at higher speeds. I was sitting in bed thinking maybe the issue isn't vapor lock, and maybe the Pierburg is starting to go? Not pulling all the fuel it should when not giving a ton of gas. Would that be a "tell?" If so, I will switch to an electric pump, when/if I do that, does anyone know where to get the plate to seal off the mechanical pump? I did this on the Bavaria but it was many years ago now and can't remember where I got that. I'll install the pump in the trunk near the gas tank and Chris mentioned changing out the fuel lines, which isn't a bad idea as they are most likely original and may have pulled some sediment up from the gas tank. I'm still mouse brainstorming here looking for suggestions from the big brains. What's weird is, other than those to times getting fuel starved while driving, and the slight surging at low speed, the car drives great and pulls nicely (for the 3.0L).
I doubt the pump is starting to go and an electric pump will still push through your mechanical pump and fuel bowls can’t empty out that fast. The 2002FAQ Store has those block off plates. I would guess that you are getting too much gas in one of the carbs, maybe a bad float, carbs not synchronized is another possibility
