MK2 1.3 engine into MK3

monkey2004 · Post by **monkey2004** » Wed May 11, 2005 10:36 pm

going back to engines the mk2 1.3 is a carb lump with no cat or lambe sensor also it has a mechanical fuel pump where as the mk3 has a cat lamba sensor but is fitted with a eletric fuel pump would the 1.3 need the mechanical fuel pump or cud i just leak the eletric 1 up

and where r the ecu on the mk2 and 3 polos cos i think i got 2 change all that stuff to.

amstrange1 · Post by **amstrange1** » Wed May 11, 2005 11:11 pm

If you need to replace the Mk3's engine, do just that - keep the Mk3's injection system and exhaust (with cat) all in place. You can use the exhaust manifold and downpipe from the Mk3 on the Mk2 head. Leave the mechanical fuel pump in place on the Mk2 head, but don't connect it up to any fuel lines. Use the electric fuel pumps and fuel injection system already on the Mk3.

monkey2004 · Post by **monkey2004** » Fri May 13, 2005 10:19 pm

oh rite wud the air fuel mixture be rite cing as the bores wud be bigger?

amstrange1 · Post by **amstrange1** » Fri May 13, 2005 10:29 pm

Like I said before, you'd be better off using a 1.3CL ECU and SPI unit from another Mk3 for that reason. Would probably run on the one litre one though.

Tahrey1043 · Post by **Tahrey1043** » Fri May 13, 2005 11:46 pm

yeah, over this way, i'm thinking unless you were to run it in quite cold climes / at high speeds with a high-flow intake at high revs it should probably be able to cope with adjusting the fuelling to cope, at least until you could get hold of a 1.3 injector (and ecu..???) that would be able to cope with such running conditions.

thats what the lambda sensor and all is there for after all - to keep it in the economy / power / emissions sweet spot no matter what, without the problems of running lean / rich that come from a choke-based setup. (granted a chip will run it a bit richer, to move towards the power end of that spot rather than the slightly leaner economy end, but hey...)

the specs even on the 1.0 injector look to be a bit in excess of what the engine can actually use, but i bet it's probably not a good idea to run it (ie the injector) flat out for very long or to push the limits of potential lean burning at high rpms. (there's at least one G owner here who can testify to what such a problem means i'm sure, and my own piston ringage is possibly due to a similar fault but on the temperature side of the equation)

amstrange1 · Post by **amstrange1** » Sat May 14, 2005 1:21 am

Tahrey1043 wrote:thats what the lambda sensor and all is there for after all - to keep it in the economy / power / emissions sweet spot no matter what, without the problems of running lean / rich that come from a choke-based setup. (granted a chip will run it a bit richer, to move towards the power end of that spot rather than the slightly leaner economy end, but hey...)

The lambda is only used for mixture adjustment at idle and part throttle. On full throttle a fixed fuel/ignition map value is used according to engine load conditions signified by the throttle potentiometer position and hall sender signal (Alpha-N style management if you're interested! Digifant/jet is Speed-density). Adjustments are then applied to this value in accordance with air inlet temp and coolant temp information.

So basically on full throttle the one litre setup may be running a little too lean - regardless of the injection unit's capacity, it will be limited by the map in the ECU.

Like I said, use a 1.3 ECU and SPI unit...

Tahrey1043 · Post by **Tahrey1043** » Sat May 14, 2005 3:24 am

fair enough then, you're the man with all the know-hows

i was mostly thinking along the lines of needing the car up and running ASAP though ... if you stuck a wooden block to the back of the throttle to stop you demanding too much of it you could get away with it whilst sourcing an injector & ecu. didnt really think it'd be a great long term idea

amstrange1 · Post by **amstrange1** » Sat May 14, 2005 10:32 am

Tahrey1043 wrote:i was mostly thinking along the lines of needing the car up and running ASAP though ... if you stuck a wooden block to the back of the throttle to stop you demanding too much of it you could get away with it whilst sourcing an injector & ecu. didnt really think it'd be a great long term idea

It'll run for sure, just how well is a bit of a lottery. It might be fine, but then again may run too lean to be safe - but for the sake of Â£30-Â£50 worth of scrappy bits it's probably not worth the risk.

monkey2004 · Post by **monkey2004** » Sat May 21, 2005 7:00 pm

ok so wat if i us all the mk2 engine with the carb? is there an ecu on a mk2 polo e reg?

Tahrey1043 · Post by **Tahrey1043** » Sat May 21, 2005 8:16 pm

i doubt you'd find a ferrari from that year with an ECU mate

far, far too old. even the entire ignition system should still be mechanical. quite amazing it has an auto choke, really.

watch out you don't get a formel-E carb either, unless you're actually on an economy lick. the jet's smaller and so it cant push through as much fuel as an ordinary carburettor might when at full throttle or choke - it can be changed for normal sized one but may as well have it proper from the start. (am i getting my era right? i'm sure the formels were around the C-to-E reg years)

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Sun May 22, 2005 3:28 pm

some continental polos had ECUs by the equivalent of C reg. The NZ was available by then (its in my rangers book anyway). No RHD mk2 has injection has standard though, and therefore no ECU.

monkey2004 · Post by **monkey2004** » Wed May 25, 2005 11:13 am

looking at the mk2 there is no ecu so 4 times being i use the 1.3 with the carb maniford on it. it has a mechanical fuel pump which i cud use but the mk3 is allready fitted with a electric one which wud be best?????

hopefully later on i can get hold of a multi point injections manifold and ecu to put on the mk2 engine but thats later!!

amstrange1 · Post by **amstrange1** » Wed May 25, 2005 11:50 am

You could use just the electric lift pump - but you'd need some sort of fuel pressure regulator. The alternative is to swap the heads over too so that you can use the Mk2's mechanical pump.

The easiest and cheapest way to do things I think is to get the Mk2 engine running on the 1.0 injection system, and just take it steady until you buy a 1.3 ECU and SPI unit. I think Karl on here has a 1.3CL ECU for sale for about Â£25, and I could probably sort you a CL SPI unit for about Â£15 + P&P after the weekend. Alternatively, 86c (Steve) on here will probably have both parts in stock.

Tahrey1043 · Post by **Tahrey1043** » Fri May 27, 2005 12:14 am

yeah, the lamdba sensor (assuming you keep the injection engine's exhaust system) should keep it from running (very*) lean and knackering your pistons / rings / valves etc so long as you don't try anything extreme with it. pretend you're running it in until you can get the right kit... i.e. try to live with only half power!

or just keep the carb on of course and live with the different foibles and characteristics it has. you might like it after all

* as it's kind of a homeostatic system it will probably be running a little leaner than normal, maybe not much, but holding steady on that side rather than dead in the middle (preferable) or just going waaaay out of line (which it otherwise might). if you cant find the parts straight away and you're not adverse to a little outlay on components and some soldering it might be worth your while rigging up a mixture checking/tweaking circuit as i've seen described here before.... a multi-LED graph style readout of what the lambda sensor output is (somehow calibrated that in the middle is the "ideal" mixture), and a zero-up potentiometer fitting between it and the ECU that you can manipulate to artificially richen the mix if the display shows it edging towards the vindaloo end of the scale. Something like that it was - originally to prevent piston destruction on unruly chipped G40s.

amstrange1 · Post by **amstrange1** » Sat May 28, 2005 1:18 pm

The lambda would only protect it on part throttle and idle conditions, the rest of the time the ECU works from fixed fuelling maps according to air inlet temp, rpm and throttle position. TBH, I doubt you'd have any problems running it on the one litre setup, but with the ready availability of the correct 1.3 items I personally wouldn't risk it.