jad Posted March 6, 2012 Share Posted March 6, 2012 Hi Guys I recently bought some clear fuel pipe to see if my fuel was draining back/air was getting in. I know I have a leak from on top of the fuel filter, from either the banjo bolt or bleed screw. I will be replacing the copper washers this weekend as they have been crushed one too many times. However ignoring this leak when I turn my car off the fuel pipe from the fuel filter to the injection pump slowly fills with air. The air is coming from the top of the filter where the leak is when its running as there are no bubbles coming from the injection pump end. I cannot see however where the fuel is draining out... There are no damp patches around the injection pump or the pipes going to the injectors. The timing case is bone dry. I also cracked the injectors off and the speed of draining did not change. At one point I took the fuel cap off and my mate said the level dropped in that tube a couple of cm's. The car runs well in general. It can be a bit lumpy at idle and when it gets cold it can be very lumpy when starting until its warmed up. It also tends to missfire, worse when cold until its been running for a short while. I recently changed the head gasket and thermostat, when it overheated (not too badly but got up to 95. It used to stay at 81 all the time). Faily sure this was due to the thermostat but wanted to remove the head anyway. The head gasket had a crack in it and one of the cylinders had been blowing into the no 6 head bolt cavity but not into the coolant or oil system. I put a proper Elring head gasket on of the correct hole size. I am fairly sure most of the irregular running problems at startup rom cold and its uneven idle also sometimes when warm are due to the fuel problem, but am not sure where to start. as I dont know where the fuel is going! Can anyone give me a idea of where to start? Thanks for your help and feel free to ask any questions of things I can check to provide more information. Jad Quote Link to comment Share on other sites More sharing options...
mat2495 Posted March 6, 2012 Share Posted March 6, 2012 When I had something very similar to this it turned out to be the connection to the sender on the top of the tank. I hadn't tightened it fully post chassis swap, and while it wasnt leasking fuel, air could get in. I would start with the leak at the fuel filter though. Quote Link to comment Share on other sites More sharing options...
jad Posted March 6, 2012 Author Share Posted March 6, 2012 I will fix the filter leak at the weekend. Its not too bad, on the last tank I got just over 32mpg but after a long run fuel runs down the heater cable and onto the rocker cover. The thing is though the filter is higher on the bulkhead than the injection pump so while that is filling with air where is the fuel going if there is no visible leaks at the engine end? I am pretty sure the tank connections are tight. Im not usually one to not doing things up tight enough..... cheers Jad Quote Link to comment Share on other sites More sharing options...
Paul Woodward Posted March 6, 2012 Share Posted March 6, 2012 I suspect when the engine is off air is leaking in at the top of the filter and the fuel is draining back to the tank. Quote Link to comment Share on other sites More sharing options...
ian_s Posted March 6, 2012 Share Posted March 6, 2012 it will just be draining back into the tank, nothing to worry about. Ian Quote Link to comment Share on other sites More sharing options...
jad Posted March 6, 2012 Author Share Posted March 6, 2012 what through the injection pump? Jad Quote Link to comment Share on other sites More sharing options...
ian_s Posted March 6, 2012 Share Posted March 6, 2012 Through the pump, and also back along the return feed to the tank. Quote Link to comment Share on other sites More sharing options...
Gremlin Posted March 7, 2012 Share Posted March 7, 2012 I also seem to have the same problem, but it only happens if my tank is nearly empty. No leaks anywhere. it runs good and strong. Till now i have not found the cause of this. If i keep it over a quarter of the tank, then its all fine. Checked all the connections to no avail, the problem is not that annoying yet, so it will stay as is, but someday i need to get doen to find the root of whats causing the fuel to drain back to the tank. G Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.