[urq] ABT ignitionbox

Sat Sep 28 00:19:24 PDT 2013

Hi Pat
Thanks for this. I'm intrigued now, given my struggles with lengthy cranking starts - how can the ecu be modified to start faster? Does this involve unsoldering and replacing a chip or some other component? If it does, where can one obtain the necessary repacement chip/part?
Regards
Keith

'87 WR

Sent from my iPhone

> On 28 Sep 2013, at 08:07, "Patrick Carlier" <p.carlier at pandora.be> wrote:
> 
> The ecu will start sparking only if it has "seen" sync between the tdc sensor
> and the cam position sensor .
> TDC sensor is a single pin on the flywheel , cam sensor is the one window hall in the
> distributor . Otherwise it can't possably know where the engine is .
>  
> So in a worst case the engine would need two full revolutions of the crank before it starts
> sparking . This is also the case with later 20V and 20V turbo engines .
>  
> I don't know if the fuel pump relay is also affected by this  , but if the pressure accumulator and check valves
> are in good order , it doesn'  really matter if the fuel pump kicks in a bit later  .
>  
> Pat
>  
>  
>  
> ----- Original Message -----
> From: Keith Lloyd
> To: William Stedman
> Cc: Patrick Carlier ; audifans urq
> Sent: Friday, September 27, 2013 10:23 PM
> Subject: Re: [urq] ABT ignitionbox
> 
> Just re-discovered this: This is what the late Phil Payne said about mods to the Mac01 ecu for the WR:
> 
> MAC01 WR ECU "Chipping"
> 
> The easiest way to increase WR performance is to hot-wire (or "jumper") the fuel pump so that it always runs with the ignition on, and then replace the spring in the wastegate with a stiffer one.
> 
> This is DANGEROUS for two reasons:
> 
> The ECU is designed to cut the fuel pump if boost levels exceed the design maxima. This does not merely occur when a stiffer spring is fitted, but also if the wastegate control hose splits or becomes blocked at the manifold end, or if the wastegate diaphragm tears. Overriding the feature in this instance may lead to bodywork damage caused by flying bits of engine.
> The ECU will also cut the fuel pump if it cannot see engine rotation. This is an important safety feature - in a serious frontal accident the engine will usually stop and the last thing anyone needs is ca. 2.5 litres of fuel per minute being pumped enthusiastically into the (hot) engine bay.
> The MAC01 ECU is sometimes modified by "chip tuners" to permit higher boost levels than stock while retaining the "dead engine" cutout feature. The most common modification is via a resistor/Zener diode bridge on the manifold pressure sensor output. A 4.3v Zener diode is soldered across pins 1 and 5 of the manifold pressure sensor daughter board - marked end to pin 1 - and the connection between pin 1 and the motherboard is replaced by a 470 ohm resistor. Unscrupulous tuners have been known to charge seven or eight hundred pounds for doing this, while referring to the process as "chipping" and even telling their customers that the ECU has indeed been remapped - although this would be pointless because the MAC01 does not control either boost or fuel.
> 
> The effect of the Zener diode modification is to clamp the maximum boost level seen by the ECU to around 1.35 bar - the fuel pump cut-out function is disabled. Severe engine problems can be expected if the wastegate diaphragm tears, if the wastegate control hose splits, or if the fueling is inadequate for the boost levels being run. Note that the dashboard boost gauge - already an inaccurate device - will reflect the boost as seen by the ECU and not the actual boost level. This provides the best method for detecting a modified ECU:
> 
> Detach the hose to the ECU from the inlet manifold.
> Attach a bicycle or similar pump with a pressure gauge to the hose.
> Turn on the ignition - it is not necessary to start the engine.
> Pump up the system until the external pressure gauge indicates 1 bar or 14.5 psi relative pressure, i.e., 2 bar absolute pressure.
> Compare with the dashboard pressure gauge. A significant discrepancy indicates a modified ECU.
> To test whether the fuel pump cut-off has been disabled, start the engine, raise the rpm above 3000 and repeat the test. The fuel pump should cut out.
> Remove the wastegate cap (CARE - spring loaded) and check the wastegate spring for the stock salmon-pink paint marks.
> Question for you: does the "fast start" mod involve disabling the fuel pump cut out safety feature (i.e. Where the engine has to attain a certain number of revs before the fuel pump is activated). If it does not i'd be very interested in knowing how the fast start mod is achieved.
> Regards
> Keith
> 
> '87 WR
> Sent from my iPhone
> 
>> On 27 Sep 2013, at 15:33, "William Stedman" <wnstedman at gmail.com> wrote:
>> 
>> Yes the stock computer can be chipped as I have one from my old 10v. And some of the things are a Fast Start and Increased boost without running lean
>> Fast Start makes it so when you are starting the car it doesn't have to crank over so many times before it fires up, Just hit the key for 1 second and it fires up!
>> The addition of a zener diode will make it run lean at top end without fuel distributor mods!
>> 
>> 
>> 
>>> On Fri, Sep 27, 2013 at 5:06 AM, Keith <spotatashleys at hotmail.com> wrote:
>>> Hi Pat
>>> As I understand it, the stock ecu can not be "chipped" in the modern sense. The only mod that can and is made is the addition of a zener diode across a couple of pins (I don't know which but there are diagrams on the net) which has the effect of preventing the ecu "seeing" full boost. (normally if the ecu recognises that full boost is being exceeded        it cuts the ignition to prevent damage). Not "seeing" full boost means that if a stiffer waste gate spring is used then greater boost pressure can be achieved without the ignition being cut. The plus is that you can gain a power increase, the downside is that this of course can put additional unintended strains on components reducing longevity. I believe a 1bar w/gate spring (standard is I think 0.8bar) and the zener diode mod provides approx 220hp as opposed to the standard 200hp on a WR motor. Your friend could swap it in to his daily driver but I am not sure he would see any benefits without an accompanying stiffer wastegate spring but others may be better able to advise on this.
>>> Hope this helps.
>>> All the best
>>> 
>>> Keith
>>> 
>>> '87 WR
>>> 
>>> 
>>> 
>>> -----Original Message----- From: Patrick Carlier
>>> Sent: Friday, September 27, 2013 11:21 AM
>>> To: 'audifans urq'
>>> Subject: [urq] ABT ignitionbox
>>> 
>>> 
>>> A friend of mine got himself a wrecked urquattro .
>>> Strted to pull it apart , end he found out that the
>>> ignition box under the glove box has a sticker on it ABT .
>>> 
>>> So he wants to kow what power gain this box could offer , and if he
>>> can simlply swap it in his other urq wich is a very good daily driver .
>>> 
>>> I don't know but maybe someone on this list does ?
>>> 
>>> 
>>> Pat
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>> 
>> 
>> 
>> -- 
>> Thank You
>> William Stedman