Heitmann

iTrader: (1)

I know this setup is more or less overkill on a std. car, but nevetheless I decided to go for it, since my dizzy was quite tired, and I liked the look without the dizzy.

But I am having an annoying misfire (feels like fuel cut) at excactly 3000rpm. It is very intermitent, and its only when car is hot that it occours. But I can drive along for many miles, without any problem, then suddenly it will occour, and keep doing it until I get to just above or below 3000rpm - it is infact that sensitive.

At some point I thought it was related to the gap between sensor and trigger, but changing the gap didn't cure it. Although it did move the misfire from 2500 rpm. to the current 3000 pm. - but I am at the absolute minimum of gap now - so gap is not too big.

I did also notice that the trigger was not centered excactly below the sensor (off by about 3 mm.) but having rectified that, so that it now sits excactly below the trigger hasn't helped either - still 3000 rpm misfire.

I still have the original dizzy setup fitted and it works faultless, when I change the wire arround.

Its timed up excactly as the original phase sensor.

question....
this sensor I am told is not very sensitive to 100% crrect timing, but could it be that the signal from the cam trigger setup is not the same as the original setup, because of the greater lump of metal moving past the sensor compared to the small trigger on the original setup. Could this make the phase signal more "lasy" and not a clear voltage spike for the ECU to read?


I really can't figure this out - so any input would be highly appriciated

thanks

daz1968

Was it a new sensor fitted when you did the conversion and are you 100% sure it is correct one and in full working order. As can't be electrical if you swap wire to distributor and it works ok. I would try another sensor if sure it is timed and gapped correctly

JamesH

iTrader: (21)

Have you tried speaking to whoever supplied it?

Heitmann

iTrader: (1)

thanks - good call, but unfortunately I have already tried brand new sensor

Turbosystems

iTrader: (5)

what ecu are you running L8?

Heitmann

iTrader: (1)

thanks - but bought second hand, so not really an option
Although I really can't see that the kit I have bought differ noticably from the other kits.

Would be good to hear from someone who are using this kit or someone who knows if the theory about the bigger metal lump making the voltage spike different to the standard setup - really can't think of anything else that would cause such a misfire at excact same rpm

foreigneRS

AFAIK the phase sensor is not needed after startup anyway

Heitmann

iTrader: (1)

appriciate you input - thanks
but I can confirm that it is indeed needed (unfortunately)

copy paste from www.bigturbo.co.uk :


so the timing shouldn't be critical, but something is not right for sure.
I should add that the rev. counter is bounching when this misfire occours. (pointing at phase or crank sensor issue) but again with standard phase sensor setup - no problems encountered.

daz1968

I have had odd misfires when it's not timed correctly to crank position. Do a double check make sure it's in right position. Other than that I can't think of anything else

whizzisat114

iTrader: (2)

Try re routing the ht leads
im sure i read someone had a missfire and that was the cause

Heitmann

iTrader: (1)

Sorry missed this one

Correct running L8

Heitmann

iTrader: (1)

Thanks for the suggestion Its pointing at 12 o'clock when the std. trigger in the dizzy is pointing at the phase sensor. Besides the larger size of the trigger I am wondering if it makes a difference if I timed it at leading edge or trailing edge instead of centered.

Thanks but I would be surprised since when switching to the std. setup the "misfire" is gone.
It is too violent to be a normal misfire - feels lime fuel cut. Also the rev counter needle wouldn't jump if just normal misfire

Thanks for the offer - I have another set I could try - but seriously doubt it because the fault is gone whenusing std. setup

Turbosystems

iTrader: (5)

tried these zetec cam sensors used on the escort cossie works cars in the 90's had the same problem you are having
seems to me the weber ecu doesn't like them just stick it back on the std one
it is only a phase signal for sequential injection
The l8 has the ability to work without a phase signal at times, working out exactly when it can do this correctly is a bit like knowing what a women is thinking lol
It can actually start without a signal monitoring battery voltage
unfortunately it can only run for so long before it decides fuck it I'm divorcing you lol

We tried all sorts to get them running reliably even with the help of the mighty Steve Philips Mr pectel himself we gave up
My advice is just stick it back on the stock phase sensor

Heitmann

iTrader: (1)

really apriciate your input - and fully agree that the sensible thing to do was just to leave the standard setup plugged in....but it has become a bit of an obsession.

does this theory sounds plausible:

the original trigger in the dizzy, is very thin and is "leaning" towards the turn of direction.

Whereas my cam trigger is "leaning" away from the turn of direction.

So in theory the original setup will give a sharper and more sudden voltage spike, whereas the cam trigger in my setup will build up the voltage spike slower due to the fact that it sences the rising edge of the trigger for longer.

so I am considering as a last resort to machine it thinner and give it a sharper edge.

does it make an sence at all what I am trying to explain..

Turbosystems

iTrader: (5)

we were using genuine works ones and they didn't work either
we gave it up as a bad job
they reckoned that they had no problems with them on the works cars
we couldn't get any of them to work reliably on the weber ecu
Good luck lol

Heitmann

iTrader: (1)

Thanks

foreigneRS

makes perfect sense. try it.

nixon_2wd

Functionality > Looks

How often are you stairing at your dizzy? Seems to me like its been a lot more now that youve actually removed it!
Go back to the dizzy and drive the car properly..

foreigneRS

why take a backwards attitude to something? if it can be improved, it should be. the ignition system is all important.

just because people don't fully understand the sensors and ecu doesn't mean that they should tell others not to mess with it.

Heitmann

iTrader: (1)

I bet they didn't fit it to the WRC cars because of looks....or a lot of others cars. If I can make it work it should actually be more reliable than the standard setup, because it is not located in the dizzy. Try making a search on here for for phase sensor problems. The amount of money spent on phase sensors for cosworths cars must be huge, simply because the wiring is prone to corrosion, and the sensor gap has to be very precise.

functionality over looks you say....that would be quite boring if all cars looked the same, no custom paint jobs, no nice alloys etc. etc. I beleive I have stated the reason for trying this setup at the top

my view too

Stu @ M Developments

iTrader: (12)

Phase sensor input is a very critical input with regards some timing strategies within the ECU firmware and can be particularly sensitive when the size of trigger is changed due to the backlash in the valve gear. When you say you have WS, what age is the driver? We revised the firmware many years ago to account for a similar issue at 3000rpm, although it wasnt to do with relocated PS, it was to do with hysteresis when calculating crank rotation speed.

Its this same speed signal you are now interfering with... so I wonder if its affecting the WS driver dwell change over? Can you get me a close up picture of the driver board please so I can confirm what firmware it has? Its a long shot, but its free upgrade so worth a stab.

Heitmann

iTrader: (1)

Thanks Stu - so the theory about the size of the trigger being the somewhat the root of the problem, could be correct.

I beleive that the kit was bought from you back in 2008





many thanks for the offer about upgrading - would not expect it to be free, since it is not really the std. setup being faulty.

let me know how I should proceed - if the pictures confirms your thoughts

Brettski mk2

iTrader: (3)

Pmed you
coil pack that I used was only for mock up and was no good but you will of tryed that I bet?

Heitmann

iTrader: (1)

No worries mate

never used the coil anyway (had one already, and this had seen better days lol )

- thanks for the heads up though

Stu @ M Developments

iTrader: (12)

Hi mate,
That little "2" on your board next to the "V1.1" signifies that you are already on the latest firmware I am afraid, so your going to need to look at the trigger more closely, sorry.

Heitmann

iTrader: (1)

god damn - I was hoping for an easy solution there
thanks for checking this out for me mate - and for your kind offer

cheers

foreigneRS

might be worth contacting RP Labs as they know a great deal about these things. send an email FAO: nikola and say nick off passionford sent you. i'm sure they'll try and help you out if you send pictures of your trigger etc

Turbosystems

iTrader: (5)

the easy solution is to run it on the std phase sensor
they only need changing maybe once every 10 years lol
it is the way the weber works that makes it sensitive to crank and phase sensor signals
Have you tried scoping the std signals at 3k and then scoping the zetec cam sensor at 3k and comparing the 2
The reason the sensor was moved was to remove it from the noisy dissy with the ht kv bouncing around
you are on wasted spark so you have solved this issue
perhaps your wasted spark plug leads are causing rf interference at the cam sensor
you could try twisted pairs as that is the latest way of doing it
you could also try screened cable for the sensor not earthed at either end

Heitmann

iTrader: (1)

You are right they are very helpfull and knowledable at RP
Have been in contact with them actually, in paralel with this thread and they advised excactly same thing as Stu did (before it was clear that I was on latest firmware already). thanks for the heads up though


I have indeed considered if scoping would give me a better picture of the difference in signal (voltage power, how steep the voltage spikes are, duration og the spike etc.) - but don't have the equipment to do it

your suggestion that HT leads could cause interference with the signal is interesting (because that would save me from another inlet cam remove/install job. lol)


So my plan is:
Try Tonys suggestion about HT leads.
If no luck, I will have the trigger machined, so the surface area of the trigger is slimmer to give a signal (voltage, spike duration) similar to the original.


will update this with my findings

thanks to everone who has contributed so far - much apriciated

Turbosystems

iTrader: (5)

or alternatively just plug THE STANDARD ONE BACK IN that works fine

Heitmann

iTrader: (1)

a small update

I have modified the cam trigger to have a smaller trigger area with the purpose to give a voltage spike similar to the original setup.



I have driven the car with the new trigger, and so far it works fine.
still to early to conclude anything, as the fault was very intermittent, so wouldn't appear on every run.

but so far, at least it looks like I have not created any other faults lol

my theory is that this cam trigger setup is often used together with other engine management than the weber marelly, and therefore perhabs better suited to receive the signal from the bigger cam trigger. Perhabs this could be the cause (if my new modified setup is working that is )

It would be great to hear from some of the folks that actually sell these triggers, and to hear if they have had troubles using this together with weber marelli

Heitmann

iTrader: (1)

Just an update for anyone interested (and for anyone searching for this topic later on)

the new setup, with the modified trigger is still working faultless.
I have run the car now at 3000 rpm for prolonged periods. I have gently accelerated past the 3000 point and decellerated (really tried to provoke the fault) but none as of yet.

I have no backup data to prove that anything has changed in the signal (I didn't scope the old trigger before I modified it) so I can only conclude based on how the car drives now.
So far I am a carefull optimist and cross my fingers that the modification have really solved it for good.