LS7 ECU E38 Issues

[3Dee]

I have a horrible feeling of De-Ja-Vue at the moment!

OK, my Car was away getting a bespoke exhaust made a couple of months ago, and prior to this it would start fine.

Since I had it back, I have concentrated on taking the engine and all that good stuff out to redo the bulkhead and check everything possible for IVA.

All is back now, and fitted, looking nice and pristine-like!

Then I got to testing the engine ciruit - ign on, and...

... the LP pump starts - CHECK
... Throttle Blade Clunks - CHECK
... HP Pump? ...Hey! Where are youuu? ..where's that 5 second burst to build the presuuuuuure? - GADAYAM! Not a peep!

... So for two nights I have been up to my arm-pits in wiring, tracing tracing....and found this so far:

HP pump will work if connected to LP pump relay to test - so the engine side and pumps are OK
Feed to the relay ... +ve good as is ground, and all wires secure and in correct place.
The HP Pump relay is fed to pin 85 from a + feed (12v) from the ECU Pin 50 (from memory) - none of this has been disturbed.
Checked continuity from Pin 50 on Plug to relay - (good)
When ign switched on...no momentary +ve feed from pin 50 at all - Nothing! No voltage, Nada!

How the heck can this happen to me?

Any ideas before I take an axe to the whole thing?

I guess the only way of telling if the ECU has gone awol is to try to find someone who can plug and test? (this is the second damn one - first was faulty from supply - but this one was working...)

Who can do this for me quickly? Any one know?

Any help would be appreciated....before I lose my mind!

Cheers

[cito quod fortis]

PM sent Keith

[Storer]

It does sound like the ECU is not sending a feed so is faulty.

Can you get hold of another to try?


Paul

[Steve_D]

Does the ECU produce a +12V at that pin or 0V ie earth?

Steve

[UltimaCH]

Keith, try and hangle Mark to lend you his ECU as I believe he is down the road from you...

[356Speedster]

Yep, I'm just down the road.... but I've got an E67 ECU

[3Dee]

356Speedster said:

Yep, I'm just down the road.... but I've got an E67 ECU

Typical Mark! your so o-b-t-u-s-e ain'tcha! Thanks all the same old chap... and YES, it IS likely you will beat me to IVA the way things are panning out for me!



Mr D - this is showing 0 volts, and I would have expected 12v for about 5 secs to prime the HP circuit, dropping back to zero - well, that is what it used to do!

So - either I can find someone that can tell me what to test (just in case something is not connected and signalling the ECU to NOT fire up, or I find another E38 to try, or get mine tested....I don't care which... but I need to do something... otherwise this car will become the MOST expensive ORNAMENT I have ever owned! ...and it won't even fit on my mantlepiece!

Edited by 3Dee on Wednesday 8th August 08:55

[356Speedster]

Sorrrryyy Keith! Dave will have the same ECU as me too, so that's no good either. Agree with you that there should be an HP prime from the ECU so it sounds like something is amiss.

I'd keep trying to get a loan E38 to drop in there to prove the point before you need to have yours looked at. There must be someone else locally that's got one you can try...

[3Dee]

Talking to someone today that happened to mention that he thought the HP Pump relay to ecu feed should provide earth to the relay not provide feed! He says most do that!

..so that got me 2 & 8ts and wondering if the relay is wired wrongly! Can anyone verify what should pin 50 from the ECU be doing?

Doesn't explain to me why it used to work and now it is not!

and totally fed up!

[3Dee]

Surprising how many people think the E38 grounds pin 50, but I got it checked, and indeed on a working system unlike most other ecus, this pin provides a +ve 12 supply to the relay! So... back to the drawing board...

..will check all connections, plug in my trusty Rev2 app and see what gives...
..then hot-wire the HP pump and see if it starts....

[pilbeam_mp62]

Is it possible that whilst you have been taking out and then putting back the engine, you have disturbed some of the work that you did when you did this ?

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[3Dee]

pilbeam_mp62 said:

Is it possible that whilst you have been taking out and then putting back the engine, you have disturbed some of the work that you did when you did this ?

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Unlikely - it is more likely that I have missed a connector, or I have a wire somewhere that is now open-circuit, so this is where a process of deduction is my only option...

...but I don't know enough about the inner working of the ECU to be sure what the logical steps should be... Bu££er!

Still - if I ever get to the end of this, I can say I learned a heck of a lot about ECUs! ..but then cos I am old, I will probably forget what knew within a week!

[3Dee]

So last night I decided to get tough with my prodigy!
I marched in to the garage and checked all the connections and then when I realised all was as it should be...

... I "R-i-g-h-t! I have had enough! You miserable little ...car- thing! You had better start - or I will beat you to an inch of your life!"
..switched on the ign... and ...Whaaaat? Both Pumps sprang into life

...ehh?

Hit the starter.. and as if nothing was ever wrong the damn thing started without a murmur!
I wiggled things again...but it wouldn't go wrong!

I DONT UNDERSTAND!

Thanks for your help ...but I am none the wiser!

Seems that doing a Faulty-towers actually works sometimes!

[MarkWebb]

See emails

[Storer]

It must have been a connection somewhere, most likely an earth.

Anyway, onwards and upwards.


Paul