2.5V6 to 3.0 conversion - ECU compatibility problems - Alfa Romeo Forum
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(Post Link) post #1 of 36 Old 07-08-13 Thread Starter
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2.5V6 to 3.0 conversion - ECU compatibility problems

Here is the story:
My 2.5 V6 CF2 removed, 3.0 in.....i was told that my old 2.5V6 ME 2.1 ecu might be used, only software must be changed. Old wire loom, 3.0 injectors, using old engine sensors except knock's....... was about to start the engine last night and strange fault codes appears.....
Injectors 3 and 6 - checked wires - OK, did FES injector test - ok.....still not trying to start the engine and wired original 166 3.0V6 CF2 ECU that friend of mine give me for checks - no injector faults, no fan, rev counter and relay errors as well.
Today i turned the engine for first time after full rebuild, started immediately, perfect rock solid idle, but throttle response was very slow, injector fault lights on the rev counter.
Removed injector 3 and 6 while engine on - there is change, so they work.
I was offered very cheap ECU from 3.0V6 CF2 but it was automatic gearbox, and i'm not sure if it can be reprogrammed.....my mapper said that maybe there is different pin-out and hardware......
Is there any chance to preserve my ecu - i compared 156's and 166's pins on eLearn and they seems exactly same.
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Rear Wheel Drive Mid - Engined Alfa 156 3.0 V6 '99 - trackday car
Alfa 156 2.0 TS '00 - daily car

Fiat Coupe 20VTurbo, GT2860RS,
water-meth injection 120cc, custom manifold, 3" Downpipe, FMIC - entertainment car

Last edited by Speedmaster; 07-08-13 at 15:02.
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A few months ago, my dad and I did the exact same project for a customer. We used the 3.0 engine from a 166 (226ps) and fitted it in a 156 which had a 2.5 engine (190ps). What we did was:
- Intake runners & manifold from a 3.0
- Injectors from a 2.5
- SMF from a 2.5 (3.0 already has DMF)
- Exhaust manifolds from a 2.5
- 2.5 ecu

Car ran and is still running perfectly. On our first start, we used 3.0 beige injectors with 2.5 ecu, and car didn't run smoothly. It had 2500rpm idle and was very jerky. If you want to use bigger injectors from a 3.0, you need to chip tune it. And if you want to use 3.0 ecu, you also need it's immobilizer, because it will not start without it. IMHO it is not worth the hassle, because you will not see any benefits from simply changing the ecu, and what power gains you expect from tuning it, you will also achieve with the 2.5 ecu...
As for bigger injectors, bosch beige 219cc injectors are nice, but stock yellow 189cc are good for 280-300ps (depends on the duty cycle), so I doubt you will even reach their flow limit on a N/A engine...
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Well i'm not having problems with remaps so far, almost 3 years only doing trackdays.
Injectors itself not a problem, i use 3.0 injectors(tested and cleaned) with GTA cams and runners.
Problem is that 2.5 ecu is hard to use with 3.0......
PS - immo was removed years ago and it's not the case......
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I did the opposite to peruccy - 3.0 motor from 166 into 156 2005 (facelift interior) - 156 ECU worked fine - we did no modification that side - car runs strong!
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Ordered 166 3.0V6 ecu from eBay few days ago, will see what will happen....
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I used the 156 2.5 V6 ecu, ran ok as it was, then drove the car to the mapper (squadra tuning in the netherlands), ran even better afterwards.
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Quote:
Originally Posted by Cuore_Sportivo_155 View Post
I used the 156 2.5 V6 ecu, ran ok as it was, then drove the car to the mapper (squadra tuning in the netherlands), ran even better afterwards.
Sorry if i sound silly, but you mean that you started the 3.0 engine with 2.5 ecu with previous software, and just afterwards did the remap????
If yes, i could try this.....what i did was sending my 2.5 ecu and friend's 3.0 ecu to the guy that did my remaps, he copied 3.0 soft to 2.5 ecu, and that's happen......
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yes, it started with 2.5 software, and ran ok, but of course we didn't trust open loop running, so no full throttle blasts...
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I am STILL running 2.5 Software - 134 wheel kW - not very far off 3.2 power
https://www.alfaowner.com/Forum/attac...p;d=1363589761

video-2013-03-16-156SW30.mp4 Video by gertiefalie | Photobucket
I have fitted BMC filter, full exhaust replacement to decat and free-flow and induction pype resonators removed for power mods - I have fitted Q2, braided brake hoses, slotted brakes, trackday grade pads and Eibach ARB on handling mods

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interesting, it should run quite lean as the real cylinder displacement is bigger than that calculated with. But it seems to be corrected by the lambda feedback. Good to know the ECU is smart enough to recover from the situation


well, no, the injection is based on MAF reading, so it injects correct amount of fuel, but just reports higher load value (because of lower displacement). Smart, smart thouse are


I guess you can see load value upto ~114% on diagnostic at full throttle

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Well many thanks for your feedback, i'll return my old modified for 3.2 cams software and with wideband Innovate lambda will report back what's happen.
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You have wideband lambdas connected to the stock ECU? Chmm, interesting. That's I was thinking about, but haven't found howto yet.
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I ran my 3.2 Gta engine in my cf2 156 on standard 2.5 management for 2 years. I then bunged it into a cf3 156 and ran it again on standard management for 2 years.

They both went fine, vey well in fact. The cf2 made well over 270bhp on a a rolling road when I first built it, No cats, at all and not much in the way of scilencers either...

I've also done similar 3.0 conversions and had no problems with the standard ecu being able to cope.

In each case I used 3.2 and 3.0 injectors respectively. I did try 2.5 injectors in a 3.0 cf3 and felt it was running a little lean.

I also ran a wideband innovate lambda and data logger unit (LM1). I tried to wire it into one of the cf3 lambda feeds but it produced the mcsf problem.

The wideband feed from the lm1 worked fine with the cf2 management though.
 
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Quote:
Originally Posted by yan.ko View Post
You have wideband lambdas connected to the stock ECU? Chmm, interesting. That's I was thinking about, but haven't found howto yet.
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Originally Posted by Chris155 View Post
The wideband feed from the lm1 worked fine with the cf2 management though.
Yes, almost 3 years wideband on my car, wired to C-32 ecu pin, works just fine.....
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Speedmaster, can ECU work with wideband? So you can see the AFR over the diagnostics?
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Quote:
Originally Posted by yan.ko View Post
interesting, it should run quite lean as the real cylinder displacement is bigger than that calculated with. But it seems to be corrected by the lambda feedback. Good to know the ECU is smart enough to recover from the situation


well, no, the injection is based on MAF reading, so it injects correct amount of fuel, but just reports higher load value (because of lower displacement). Smart, smart thouse are


I guess you can see load value upto ~114% on diagnostic at full throttle
not quite... the injectors are changed aswell from 2.5 to 3.0 versions. not sure anymore how much bigger they are, but with 2.5 injectors you'll reach the limit around 220-230 bhp.
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2.5V6 CF2 7626715 0280150702 EV1 150g/min @3bar
2.5V6 CF3 60664640 0280156039 EV6 137g/min @3bar
3.2V6 CF3 60665644 0280156038 EV6 172g/min @3bar

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Well, the question is what injectors (and MAF) are Chris and Gertie using with unmodified 2.5V6 ECU.

If non 2.5V6 ones, then the mixture calculation is really messed and lambda correction has hard days putting the mixture right
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Standard maf and 3.2 / 3.0 injectors. The ecu reads the lambda(s) and has sufficient scope withing the fuel trims to compensate for the bigger injectors.
 
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Speedmaster, can ECU work with wideband? So you can see the AFR over the diagnostics?
You can't just plug a wideband lambda into a cf2 ecu. You need a processor to convert the signal into a narrow band feed it'll understand.

I used an innovate lm1. It has an output that you splice into the wiring loom. (I cut the connection block off and old sensor and used that)
 
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Quote:
Originally Posted by yan.ko View Post
Well, the question is what injectors (and MAF) are Chris and Gertie using with unmodified 2.5V6 ECU.

If non 2.5V6 ones, then the mixture calculation is really messed and lambda correction has hard days putting the mixture right
I went from CF2 2.5 V6 to CF2 3.0 V6 injectors
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We ran a 3.2 engine in a 156 V6 CF2 and used the original 2.5 MAF and 3.2 injectors.

We also ran a 3.0 engine in a 156 V6 CF2 and used the original 2.5 MAF and 3.0 injectors, I can't remember if they were CF2 or CF3.

Neither reported any errors.

Yan.ko is there a problem with load values going over 100%? Will the ECU retard timing more than if it measures the load at 100%? Presumably it can be remapped so that load values remain in the normal threshold?
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Well, no, it's not a problem. This is actually how ECU treats turbo/supercharged appliances.
Internally the engine load is represented by injector opening time (pure and filtered). And all maps are based on this.


Btw. anyone ever tried Spartan Lambda Sensor from 14Point7?
http://www.14point7.com/Support/Soft...ser_Manual.pdf

Not sure if it always simulate λ=1 voltage on the brown line, or translates actual AFR to the narrowband voltage.

EDIT
Eh, I should read properly, brown is fixed to the λ=1 voltage. But it's way to go, just have to find lambda linearisation map, modify it and wire green to the ECU.

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156SW 1.9JTD: GTB2060VKLR turbo, performance cam&head, WM injection, 6speed Q2 gearbox, 4p Brembo brakes, 2.5" stainless exhaust, FMIC, upgraded sensors, lowered & stiffened suspension, own remap
GTV 3.0V6 24v: C30-94 charger, short gearbox with Quaife ATB, big 4p Brembo brakes, SMF, lowered suspension, custom freeflow equal lenght x-pipe quad tips exhaust

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Quote:
Originally Posted by Chris155 View Post
You can't just plug a wideband lambda into a cf2 ecu. You need a processor to convert the signal into a narrow band feed it'll understand.

I used an innovate lm1. It has an output that you splice into the wiring loom. (I cut the connection block off and old sensor and used that)
Hi , after reading a couple of threads , and facing the oportunity to buy a dead 156 V6 I did and swaped the dead engine with a 3.0.
Problem is it's a CF3 .
I'm running 100% 2.5 peripherals and the 3.0 engine. Engine is strong but it doesn't seem as strong as it should.
I would like to buy a wideband to check AFR , and the best bet I think would be to replace the 2 lambdas in the manifold before the cats.
My main question is how to emulate the original lambdas accurately? I can't find a datasheet to replicate the 'curve' in the innovate controller analog output.
Also , are the lambdas the same for front and back differing only in the lenght of the connection (it makes sense in my mind).

If I find a remap must be done due to open loop AFR , should I get hold of 3.0/3.2 injectors first?
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Quote:
Originally Posted by drpancho View Post
I would like to buy a wideband to check AFR , and the best bet I think would be to replace the 2 lambdas in the manifold before the cats.
My main question is how to emulate the original lambdas accurately? I can't find a datasheet to replicate the 'curve' in the innovate controller analog output.
Zeitronix Zt-3 : Wideband Controller and Datalogging System

The Zeitronix Wideband kit is a peach - It has a programmable narrowband emulator output. You also get a 2" display that you can fit in your dash.

I have one of these in my race car. When I took my car for dyno tuning - the guy at first worked off his own AFR, then saw the Zeitronix is as accurate as his own AFR, and used that for the rest of the tuning effort

Last edited by Gertie; 03-08-15 at 11:47.
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