| Author | Message | ||
     Edward Mckinley Experienced User Username: ed_mckinley Post Number: 58 Registered: 10-2019 |
My 1989 Corniche II blew the fuse in block 2 B5 (fuel injection) the other day. It seems this has happened before as the previous owner had installed a mod taking the wires from the back of fuse block and installed an aftermarket fuse holder for the 20 amp fuse. I have owned the car for over 10 years and never had an issue until Friday when the fuse blew and melted the fuse holder. I read on an older post that RR had recommended this as a repair for fuse blocks that weren't making good contact but it seems there should be more to this story. It appears this fuse powers the engine run sensor but I wouldn't expect that component to cause this type of failure. Time for a replacement fuel pump? Any ideas would be most appreciated. Thanks Ed | ||
| michael vass Frequent User Username: mikebentleyturbo2 Post Number: 795 Registered: 07-2015 |
Yes I've seen this mod but I'm sure it increased the rating to 30A. Mike | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 59 Registered: 10-2019 |
I guess I'm wondering why the car runs great for 11 years and then one day draws enough amps to fry the fuse. Perhaps some kind of restriction has developed causing the fuel pump to over-work? | ||
| michael vass Frequent User Username: mikebentleyturbo2 Post Number: 796 Registered: 07-2015 |
I think you'll find it actually draws 20A and the fuse runs hot and eventually gives up. Mike | ||
| Alan Dibley Frequent User Username: alsdibley Post Number: 388 Registered: 10-2009 |
"Idle thoughts of an idle fellow." 20 Amps suggests a big DC pump motor (240 Watts) - a significant fraction of the maximum alternator output, and about 1/3rd of a HP. Can the pump really consume 240 Watts as a running load and stress a 20Amp fuse? I know the pressure is high but the flow is relatively small. On my fuel-injected 1988 Citroen CX25 GTi - 2.5 litres - the fuel pump is supplied by a feed with TWO heavy gauge connectors direct from the battery post terminal WITH NO FUSE !!! (unless there is some device inside the pump??). A DC clamp meter on the wiring shows 4.8Amps idling. Too difficult to measure it under power. An engine about three times the size might use about 14 Amps idling(??), and 20 Amps is reasonable with a bit of throttle, so a 30Amp fuse seems sensible. So what - Any thoughts? Or who cares? Alan D. | ||
| michael vass Frequent User Username: mikebentleyturbo2 Post Number: 797 Registered: 07-2015 |
Hi Alan You're right, but on this fuse is also the ignition system , pump and other stuff . This pump also runs a constant 6 bar of pressure so is working hard. Mike | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2579 Registered: 09-2004 |
Unfortunately Alan is not correct having owning a GTI turbo and the prestige!! From past rare experience the GTI has the live feed from the ignition switch to the ECU that controls a relay live to pump, maybe a double type relay. The ground earth is carried out by the other connection on pump. As for Edwards fault I would first check fuel filter flow then check flex type fuel lines for internal restrictions, due one cause maybe to the E10 especially if car is not used all the time. Horrid fuel! | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 60 Registered: 10-2019 |
I don't see any wires going to the tank so I'm guessing it does not have the pre-pump. I don't know if my car SCAZD02A9KCX29169 would not have been fitted with one or if it was removed by the previous owner. I plan to drain the tank and check to see what the inlet looks like, I believe there should be a filter in the tank | ||
| Alan Dibley Frequent User Username: alsdibley Post Number: 389 Registered: 10-2009 |
Hi Patrick Re Citroen CXs, of course there's a relay, otherwise the fuel pump would run continuously, but there is NO FUSE - which was the point I was making. Sorry everyone, for sending the thread off-topic. Alan D. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2583 Registered: 09-2004 |
Alan, I picked up on the two heavy connectors from the battery post with no fused implying something was in the pump! I explained the relay energized from ignition and the pump is controlled by the ECU. Off topic but keeping the brain active  | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 63 Registered: 10-2019 |
I removed the fuel line going tank to pump and removed the retaining ring to inspect the in-tank filter (UE 21840). The picture attached shows the condition. Obviously I'm going to replace it along with the main fuel filter. As this filter got dirty the pressure increased until it just pulled itself apart I'm guessing.  . | ||
| Edward Mckinley Experienced User Username: ed_mckinley Post Number: 64 Registered: 10-2019 |
Perhaps you all already know about this site but I found it helpful for substitute part numbers https://www.fuelfilter-crossreference.com/convert/BOSCH/71039 . |
