[Mk2] [Turbo] Faulty Alternator ( diagnosed but wanted advice )

[JLW]

Hi Guys

Now as I have listed in my recent update on the car,
http://www.imoc.co.uk/forums/viewtopic. ... &start=280
after returning from its initial mapping session at Fensport, it was having
issues that I believed to be boost cut. Turns out it was a faulty alternator spiking
to 18v and my Link G4 Storm ecu having a 18v map cut was causing
the sudden cut outs on power.

Now my issue is that they mapped the car at the 16v that they then found it
running at after the mapping gear was re-installed. Surely as cars tend to
run lower than this they should have noticed this in the first place ?

My problem is, that I had to take a day off work, drive the 2 & 1/2 hours there
and back, costing a tank of Shell V Power, and pay for an hours labour to
diagnose / fit mapping gear the first time. Fair enough, however Adrian
mentioned that it will need to go back up there for 2 hours mapping, after
the alternator is re-conned to tweak the map back down to the correct voltage.

Here inlays my question. Does it really need mapping again ( Simon at YVS ,
my engine builder, doesn't seem to think so ) Because that means another day
off work and all the above, but with the added cost of two hours labour.

Im in the frame of mind to be asking for the 2 hours of mapping to be free of
charge as they surely should have seen that it was running high voltage on the
initial mapping session ?

I know this is more of a question of practice but I'm honestly stuck on how
to proceed, money is tight this month and I'm currently driving the MR2 out of
boost in this amazing weather as advised by Adrian.

to reiterate, does it need mapping again ? and if so, should I be paying ?

thanks,

Jordan.

[androo007]

In my opinion, the mapper should have noticed from BASIC pre-mapping checks that fundimentals are correct.

Were they legally obliged to and responsible? No.

Will they likely do it as a good faith item? Likely.

Does it need remapping? I don't understand why it would need mapping.

Fuelling wouldnt have changed
Optimum Ignition timing wouldnt have changed (i.e the spark wont be weaker / better / stronger).

Would I do the drive to double check everything if it was offered FOC? Absolutely.

Only because it was mapped with an error - even if it takes them 30 minutes for a check, it is then back to them for any other problem. Otherwise it's easy for them to come back later and say you knew wyou had a problem, why didn't you fix it after?

[SonicSW20]

edit - see Rob's post below!

[androo007]

The main thing I missed above the first time is that Fensport have told you to go back to have it tweaked.

Therefore you must do - otherwise they can wash their hands of you given any future problems.

Whether they charge or not is how you argue it and how they see it.

[C35Rob]

firstly.. yes, they should have known it wasn't right and should have contacted you to highlight any issues prior to tuning, rather than soldiering on regardless..

does it need remapping?

it certainly needs to be checked, this is where "road mapping" falls flat on it's face because it's stab-in-the-dark levels of accuracy, you can there-or-thereabouts get AFR's to a target level, but without steady state tuning on a dyno there's no way of optimising fuelling and especially ignition timing to generate maximum power and efficiency throughout the rev range in all driving conditions. anyone that says different is simply lying to their customers, or lying to themselves too.

(that's assuming lots of 'tuners' aren't just out there pulling timing, making global fuel corrections and screwing boost into things... which they are)

anyway, that's off on a tangent a bit.

so why does it need to be checked? fuel injectors behave differently at different voltages (known as injector lag vs battery voltage), apply 10v to an injector and it will take X time to fully open and X time to fully shut,



apply 18v to the same injector and that time will be different, as will every voltage in between and it isn't necessarily a linear slope either.. IF, and it's a big IF the injector data has been input into the ECU correctly then the engine will operate correctly at any voltage in its operable range.. if it hasn't been input correctly into the ECU (i.e if someone couldn't get, didn't know or just couldn't be ar$ed to supply the ECU with the correct data) then your fuelling may be ok at the exact voltage it was tuned at because despite not having the correct injector data you can kind of work around it by altering the base map (this is the wrong way to do it) as soon as you stray from that voltage your fuelling will be wrong.

infact, if it's the same software as the G4+ ecu, the injector dead time table only goes up to 15v....

obviously voltage will have a similar effect on the ignition system too, as in batt voltage vs ign dwell.. meaning it takes X time to charge a coil at 14v, less at higher voltage and more at lower voltage.. again, if these compensation tables are incorrect you could end up with a weaker spark than you need, or burning your coil out. there may also be an ign advance vs batt voltage table in your ECU (I can't remember which link you have tbh)

[SonicSW20]

firstly.. yes, they should have known it wasn't right and should have contacted you to highlight any issues prior to tuning, rather than soldiering on regardless..

does it need remapping?

it certainly needs to be checked, this is where "road mapping" falls flat on it's face because it's stab-in-the-dark levels of accuracy, you can there-or-thereabouts get AFR's to a target level, but without steady state tuning on a dyno there's no way of optimising fuelling and especially ignition timing to generate maximum power and efficiency throughout the rev range in all driving conditions. anyone that says different is simply lying to their customers, or lying to themselves too.

(that's assuming lots of 'tuners' aren't just out there pulling timing, making global fuel corrections and screwing boost into things... which they are)

anyway, that's off on a tangent a bit.

so why does it need to be checked? fuel injectors behave differently at different voltages (known as injector lag vs battery voltage), apply 10v to an injector and it will take X time to fully open and X time to fully shut,

Image Replaced With URL For Quote http://www.mre-books.com/sa135/images/sa135_55.gif

apply 18v to the same injector and that time will be different, as will every voltage in between and it isn't necessarily a linear slope either.. IF, and it's a big IF the injector data has been input into the ECU correctly then the engine will operate correctly at any voltage in its operable range.. if it hasn't been input correctly into the ECU (i.e if someone couldn't get, didn't know or just couldn't be ar$ed to supply the ECU with the correct data) then your fuelling may be ok at the exact voltage it was tuned at because despite not having the correct injector data you can kind of work around it by altering the base map (this is the wrong way to do it) as soon as you stray from that voltage your fuelling will be wrong.

infact, if it's the same software as the G4+ ecu, the injector dead time table only goes up to 15v....

obviously voltage will have a similar effect on the ignition system too, as in batt voltage vs ign dwell.. meaning it takes X time to charge a coil at 14v, less at higher voltage and more at lower voltage.. again, if these compensation tables are incorrect you could end up with a weaker spark than you need, or burning your coil out. there may also be an ign advance vs batt voltage table in your ECU (I can't remember which link you have tbh)

Interesting read

Edited / removed my speculative post as it's wrong

[JLW]

Hi Guys

Really respect and appreciate the feedback,

Rob I read your post, I took most of it in, but struggled on the finer points
lol, but thats me. I will 100% be taking it back to them though, thats one
thing I can clearly understand from that.

I personally will push for FOC on the map alterations, and will explain my case.

just to finally touch on this subject, will it be safe to drive up cautiously
once the alternator has been re-conned ? I'm assuming it will.

[C35Rob]

will be fine to drive off boost, feel free to give me a call if you want to chat over it mate, but the short story is it's their F up and they need to make it right

[JLW]

will be fine to drive off boost, feel free to give me a call if you want to chat over it mate, but the short story is it's their F up and they need to make it right

Thanks Pal, yeah I'm gonna whip the Alternator off asap and get it to the
local electrical automotive specialist to get it re-conned and then will call
and speak to Adrian. Its going to cost me to take a day off and spend the £50
for fuel getting there and back anyway. So I'm not going to be "quids in" !

[JLW]

Gonna whip the alternator off this week, any specifics I need to be aware
of when removing ?