The V8 Owners Forum -

What is the trigger wheel arrangement?, the standard GEMS one in the flywheel?

Chris.

Its a 3.9 rover with trigger-wheels.com wheel on the front running a ford sensor.

It came with a diyautotune loom, the one where all the wires are actually printed onto the wires.

That loom had VR input a single wire which was shielded - so i used the sheield as the -Ve on the sensor.

Just noticed on their site now that he shows it as twisted pair with a shield - I wonder if that is my problem?

Updated loom:
http://www.diyautotune.com/catalog/1239 ... b1d15f8b7b

Any signs of a tach signal problem looking at it with MegalogViewer? It's one of these things that may work just fine - or not. But I'd only ever use a good twin screened cable - that is what Ford used with EDIS.

DaveEFI wrote:Any signs of a tach signal problem looking at it with MegalogViewer? It's one of these things that may work just fine - or not. But I'd only ever use a good twin screened cable - that is what Ford used with EDIS.

Not sure i follow you - the screen shots are showing a duff tach signal.
I dont know how the toothlog should behave when you rev it - hence the posted screenshots. Phil Ringwood's docs say look for additional or missing teeth in the log - i'm not seeing that. Just a decay and randomness to the heights.

All original files are here:
http://mez.co.uk/westfield/problem/

Along with a text file explaining each one:

first go.msl
First ever start up log, running 36-1 wheel. Fuel only. Dizzy
@761 seconds the eratic speed is seen.


hold at 1200 steady.msl
Holding at around 1600rpm, showing a clean signal at this RPM.
Wideband warms up from 504 seconds onwards.


On dizzy hold steady.msl
From 3751 seconds onwards, we bring the revs up into the problem area and hold it there.
Eratic speed evident.


trigger log on dizzy.csv
1-22 are normal running at less than 2000 rpm.
25-29 and records 44 to about 51
Basicly anywhere it drops lower and the single ones get higher are when we see eratic revs.

regards,
Eliot.

Sorry - this thread seems to have jumped around a bit.

You're using a VR sensor direct to MS? Have you tried any adjustments?

http://www.megamanual.com/ms2/pickups.htm

Had a quick look at your pics and it appears to be missing either the last tooth before the gap or the first tooth after the gap.
Either way its going to be alignment of the sensor to the wheel.

Its not resetting, which is good.

I would start with screened cabling all the way from the VR sensor to the ECU, ground the screen at the ECU end only!!

Also ensure the VR sensor is perfectly central to the wheel, I have had quite a few where they are slightly off center, this causes issues. Also ensure the sensor is 0.75mm from EVERY tooth.
Do another tooth log and see how that looks.

And let that be a lesson for you, next time buy an ECU from me
thanks
Phil

Eliot wrote:Its a 3.9 rover with trigger-wheels.com wheel on the front running a ford sensor.

It came with a diyautotune loom, the one where all the wires are actually printed onto the wires.

That loom had VR input a single wire which was shielded - so i used the sheield as the -Ve on the sensor.

Just noticed on their site now that he shows it as twisted pair with a shield - I wonder if that is my problem?

Updated loom:
http://www.diyautotune.com/catalog/1239 ... b1d15f8b7b

I remember reading recently that they/DIY have upgraded that shielded wire recently,maybe they was hearing of problems with your kind earlier loom type,bound to of been a good reason i would imagine.

Or use the standard GEMS sensor. I have used it with MegaJolt and it works just fine.

Chris.

This is on my mates westfield, not my P38 or Dakar (both of which run edis!).

Should the shielded wire for the VR sensor be twisted? - Maplins microphone cable isn't. I'm not sure if the triggerwheels or polevault stuff is either:

http://www.polevolt.co.uk/acatalog/Screened_Cables.html
http://www.trigger-wheels.com/store/con ... uk/d9.html

Elliot,
drop me a mail with your address and I will send you a length of the stuff I use in my looms.
I dont think thats the issue though, its not helping, but I think its alignment of sensor to wheel, but you do need screened cable,
Phil

Thanks Phil.
The cable is screened - its just single core. So i used the screen as the negative from the sensor.

Ideally it wants to be twisted and screened. The screen is connected at one end only, and the two twisted wires are the sensor connections.

Chris.

Just had a thought, swap the wires over on the VR sensor, that will give the same fault you have thinking about it, as the cross over would be further away if the phase is out,
Phil

Ok live reports from my mates garage.
Started by realigning the sensor - this moved the problem to about 4k rpm.
So I then swapped the VR sensor wires over and we now have a clean tach signal Well done phil - dead on the money.

Reconnected coil packs and still seems good as well. Now need to plumb the radiator back in so we can bring it up to temp and see how things look on the wideband.


We have also scored a Snap-on 5 gas analiser - needs collecting and calibrating - but we will be able to see exactly whats going on once we have it.

Wouldnt ignition timing be all wrong if the wires are the wrong way ? It would be seeing the wrong edge of the signal every time ?
Some ecu's wouldnt even recognise the rising edge as a trigger when wired the wrong way round

That's why those bar graph scope readouts dont make any sense to me. There simply isnt enough information. ( and I'm not slagging, because My DTA is exactly the same )

if the polarity was wrong on a full scope image, it would have been immediately apparent