Gromit Posted May 31, 2008 Share Posted May 31, 2008 Hello All, I've just about finished my veg oil conversion and have run into a bit of a problem. I'm just trying to get it to run on diesel at the moment. The fuel has been replumbed so that the diesel side looks like this: The return line only returns to the veg tank (via the return valve) while flushing after switching from veg to diesel. In normal operation, the IP is basically drawing from the spill rail return as well as the diesel supply. The problem is when trying to prime it there was air in the supply to the IP, which I traced to the return line from the IP. I disconnected the return from the supply valve and it primes fine and runs without out air in the system. Reconnecting the spill rail and the air is back. I've checked the return pipework and there are no air leaks. So to my question; is there some way the that IP itself could be introducing air into the spill return? Any idea where to look? The IP was reconditioned about 2 years ago. Cheers for your input. Looks like I'm not going to be running on veg just yet Quote Link to comment Share on other sites More sharing options...
Gromit Posted May 31, 2008 Author Share Posted May 31, 2008 I've been reading up on other people's problems with air in a looped return line and it seems to possibly be caused by partially leaking seals in the IP. Is there such a thing as an air bleed valve that would automatically purge the air from the return line? I don't really want to have to overhaul the IP again Quote Link to comment Share on other sites More sharing options...
white90 Posted May 31, 2008 Share Posted May 31, 2008 When I had the diesel veg system the probs were just down to clips not tight enough once purged it was important to not run out of diesel from the separate additional tank but once running all remain well. is it a home brew set up? Quote Link to comment Share on other sites More sharing options...
Gromit Posted May 31, 2008 Author Share Posted May 31, 2008 This is the diesel veg system. If I remove the banjo on the return from the IP, the pipework is airtight. Reconnecting the banjo, with new copper washers, and there's air coming in from the IP itself. Quote Link to comment Share on other sites More sharing options...
white90 Posted May 31, 2008 Share Posted May 31, 2008 spill returnn pipes ok? I'll look out the paperwork if I still have it I removed the entire system from my 90 Quote Link to comment Share on other sites More sharing options...
Gromit Posted May 31, 2008 Author Share Posted May 31, 2008 spill returnn pipes ok? Yep, when I removed the return banjo, the spill pipes were still connected. I blocked the banjo, and sucked on the supply No leaks. Reconnected the banjo and I can hear the air bubbling through the system. Quote Link to comment Share on other sites More sharing options...
white90 Posted May 31, 2008 Share Posted May 31, 2008 Diaphragm under the FIP cover ok? Quote Link to comment Share on other sites More sharing options...
Gromit Posted May 31, 2008 Author Share Posted May 31, 2008 Diaphragm under the FIP cover ok? Thanks for the suggestions so far Can't actually get the top screws off the FIP with out damaging them . I've a boost gauge which shows all is normal and the fuelling seems to increase with boost. Not sure whether that confirms the diaphragm is ok or not. Quote Link to comment Share on other sites More sharing options...
white90 Posted May 31, 2008 Share Posted May 31, 2008 can't see how air is getting in there otherwise the screw=large screw driver and a small hammer to tap them around I replaced all the screws with Torx bolts. when I commissioned mine I put a 12v feed onto the purge solenoid to keep it open to bleed the air it soon emptied the aux 22l diesel tank back into the main tank have you checked there is diesel still in the red tank? Quote Link to comment Share on other sites More sharing options...
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