relays in footwear.

[ewan221]

One is fuel pump, what's the other one ? And are they both same part number.
Oh and found what was draining battery - was the alternator so new one of them ordered!

[pwd95]

You have relays in your shoes??

Sorry couldn't resist...

Metal relays are both the same. The new ones are brown. Can't remember what the other one is for now either.

[QBee]

pwd95 said:

You have relays in your shoes??

Sorry couldn't resist...

Metal relays are both the same. The new ones are brown. Can't remember what the other one is for now either.

The other one is for the ECU. I am not 100% convinced that they are the same, but anyway if you do have a fuel pump relay issue, swapping them over by transferring the problem to the ECU relay may well give you the same symptoms and fool you completely. Better to get a spare pair of relays for the test - they are only about a tenner each.

PS, ducking hell (yes, I had a Nokia phone once ), predictive text can be a real pain

[spend]

The 'other' one is the MAIN relay, that switches everything on ~ you need the injectors powered up separate from the fuel pump during 'priming - cranking - start - all running cycle' if you think about it.

The fuel pump relay also powers up the purge valve and other periphery (on the 'extra' pin out ~ so a std relay can be used to run just the fuel pump to test/get you home in emergencies)

In short you need a twin make/break relay in the main, but a single make/break (nick horn/lights relay) should run the fuel pump temporarily (albeit less purge valve + lambda but enough for testing & limp home mode).

[QBee]

Thank God for that - a man who knows. For clarity and our/my future reference Dave, are the two footwear (see what i did there?) relays the same as each other then, or is the fuel pump relay different to the main one?

[ewan221]

Bloody auto correct ! Ha Ha

[shake n bake]

The alternator was draining the battery or not charging? I've just had a series of alternator/battery issues and think I know the system pretty well now! :-D

[ewan221]

it was sucking battery dry !

[spend]

QBee said:

Thank God for that - a man who knows. For clarity and our/my future reference Dave, are the two footwear (see what i did there?) relays the same as each other then, or is the fuel pump relay different to the main one?

They are the same, both twin make & break relays with diodes... but as I said any twin make & break + single make & break (in FPR) will allow car to run, hence I've always advised having a twin make & break as spare as it will work in most positions to get you home (except for the 70A ignition relay)... & IS essential to get you home if the main relay fails (or swap the FP relay to main & put a single make/break in the FPR ie steal horn relay as emergency IYSWIM).

Note use proper relays as default ~ the information I am giving is so you can hopefully test & get home if either fail. TBH there would probably be nothing wrong with putting diodes in the loom and using common non-diode/diode relays if you so wished.