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[rog]

My 2012 Bullet B5 EFI keeps blowing one of the three 20 amp fuses. Using the wiring/circuit diagrams produced by Scalyback and Steve Thackery I've identified the fuse as the one that protects the power relay and hence the ECU and fuel injection system as the lights and horn etc work ok and the reg/rect is working perfectly. The problem has occured 3 times and although a new fuse will blow if it is replaced immediately, a replacement fitted some hours later always seems to be ok! As the sidestand switch/relay is a known problem area (and is linked to the power relay) I tried disconnecting the sidestand switch and the bike did over 300 miles before the fuse blew again. At the weekend I borrowed a multimeter with a 100amp scale and connected this in place of the fuse. When the ignition is switched on the fuel pump pressurises the the fuel system and the MIL light goes out as it should after all the sensors etc have been checked. However, when the fuel pump is running the multimeter shows nearly 40amps. When it stops and the MIL goes out, the meter only reads about 1 amp. If the fuel pump is disconnected the meter reads about 10 amps until the MIL goes out whereupon the reading falls back to 1 amp again. With the engine running the meter reads about 39 amps most of the time but it does hunt occasionally, sometimes giving a higher reading and on one occasion it fell back to 10 amps briefly. Having been unable to find any obvious wiring problems I'm wondering if the pump itself is at fault, but I don't fance forking out for a new one just to find out! Anybody got any other ideas, or experienced a similar fuel pump problem?

[jefrs]

Stating the obvious but fuses blow because something is drawing too much current. The diagrams are confusing. Some show three fuses, other four. Sometimes two fuses are shown in series which is wrong, a mistake in the diagram. I found the Scaleyback diagram reasonably accurate for my 2014/15 C5 EFi apart from the fuse values. The big fuse I found to be on the charge circuit (clue) but when it blew the MIL went out (clue).

I traced the fault to the three bulbs in the instrument - low-fuel, MIL and illumination. Two had blown but the third had managed to short the system which was blowing the fuse. You may not have the same fault but I doubt it is the ECU (it would be working at all). It could be the battery (NB). If the battery is charging at what? 39 amps then that is wrong. A dead cell can short out and draw huge currents on charge: battery test time, check electrolyte and cell volts.

Bulb failures were due to poor quality oem fitment, oem fuses were also corroded, replaced the lot.

You need to trace the circuit with your meter looking for a short. Something will be drawing more than 20A i.e. less than 12/20 = 0.6ohm (near enough short circuit).

[jefrs]

typo (it would not be working at all)

[jefrs]

The side stand merely dumps volts to earth from a relay, it's not the side stand switch but could be a relay especially if oem.

Your bike is not old enough to develop a serious fault with the alternator but due for the oem bulbs, fuses and relays to pack up. Some of the indian spade connectors are a bit on the thin side and could have come loose enough to short something. The headlamp casquette is a right old plumber's nightmare inside.

[rog]

Thanks for your thoughts jefrs. I hadn't thought about a blown bulb so i'll check these tommorrow. As for the wiring and connectors, I'm slowly working through them but haven't found any nasties yet.

[Michael]

Common places to check... Behind headlamp - loads to go wrong there! Tail light wiring loom - it gets wet and/or rubs through and causes problems. Spade connectors everywhere, but especially on relays. The switchgear can fail too - check for signs of heat damage to the loom. You don't want to buy a fuel pump just to check... your one seems to be working, but have you checked the cost??!!!

[jefrs]

These problems are usually simple to find. The fuel pump is worrying, 40 amps is about 500W, good grief. Can you disconnect the pump and run it straight from the battery through the ammeter? The pump should not run continuously, on my C5 it has a 15A fuse there, they appear to be slow-blow i.e. they may take more than their rated value briefly. Or it may mean they changed the pump on the later model.

[jefrs]

Other thought, the ammeter you borrowed may well not be calibrated. Such things are known to be way out on readings.

[rog]

You are spot on jefrs - the meter is miles out. I couldn't get my head around 40 amps - it just didn't make sense. I decided to chance my own meter, the highest range of which is 20 amps, and guess what, the reading with the fuel pump running was only 4-5 amps . I'm now starting to go though the wiring and connectors more methodically as the intermittent nature of the fault suggests that is where the problem lies as both you and Michael have suggested. I've have already found three wires worn through on the wiring to the rear light cluster (thanks Michael)and I'll keep plodding along until hopefully I can report success!

[jefrs]

According to my users manual "Classic 50 Owners Manual 2015.pdf" (which /is/ different to the indian one and corrected from the one in the booklet), juice for everything except the starter goes through the big fuse (15A on mine) and then that branches to the 10A ECU fuse (always live then) and the IGN Switch. From the IGN (now switched) it branches to the Lighting 10A FSE and the Signalling 10A FSE (which is indicator flasher unit, horns, low-fuel sensor, front and rear brake switches). That makes four fuses, three 10A which all run through the 15A in series.



I will check as I fit the Autotune tomorrow but I thought there were but three live fuses and three spares, I may be wrong: I will be checking as I do need to connect the AT-200 box to a switched IGN-ON +12VDC, the nearest likely suspect is the back of the 'Signalling' Fuse.

I may be able to check my fuel pump current on a Fluke if the connectoid is convenient, if.