2 Row Vs 3 Row Mi16 Ecu's

[dino20vt 3]

Keep seeing snippets mentioning two and three row ECU's, whats it all about?

 

Cheers

[kyepan 291]

3 row has knock sensor, later 3 row also has cat and llamda sensor

[Simes 248 2 Cars]

3 row has knock sensor, later 3 row also has cat and llamda sensor

 

ECU ending with 355 is the early 3 row with the knock sensor.

 

2 row is Motronic 4.1

3 row is Motronic 1.3

[Miles 331 1 Cars]

You'll be hard pushed to Find A Lambda equiped Mi loom and ECU, I;ve never seen any 405's with a CAT (1.9's that is)

[Tom Fenton 1,526]

I owned one for a time, 3 row ecu with knock and lambda, it was in an early 91 405Mi16 1.9 with air con too.

[pugman211 0]

You'll be hard pushed to Find A Lambda equiped Mi loom and ECU, I;ve never seen any 405's with a CAT (1.9's that is)

 

Are they the 3 row ecu's that end in 161??? If so i've got one of them. Well, i know the engine is ouf of a 405 and has a lambda sensor on the loom.

[GLPoomobile 958]

Presumably a 3 row ECU has the pins arranged in 3 rows, as opposed to the 2 row arrangement of a 2 row ECU.

 

I bloody hope I'm right with that or I'm going to feel a right twat!

[pugman211 0]

yes, thats the difference between a 2row and 3 row. Other than i heard the 3row has a slightly better map than the 2row (not confirmed before i get shot down) lol

[dino20vt 3]

3 row has knock sensor, later 3 row also has cat and llamda sensor

 

So do knock sensor equipped cars have a dizzy like a 2 row?

[Anthony 1,000]

So do knock sensor equipped cars have a dizzy like a 2 row?

All 1.9 Mi16's use a dizzy cap/arm setup.

[Simes 248 2 Cars]

Are they the 3 row ecu's that end in 161??? If so i've got one of them. Well, i know the engine is ouf of a 405 and has a lambda sensor on the loom.

 

Like I said in an earlier post the ones with a knock sensor end in 355

[Anthony 1,000]

Like I said in an earlier post the ones with a knock sensor end in 355

That's correct for non-CAT 3 rows (end in 354/355) but the CAT 3 row ECU's have a different part number (end in 158/161/167 according to Petert's website)

[dino20vt 3]

All 1.9 Mi16's use a dizzy cap/arm setup.

 

How is the timing changed (ie advanced/optimised) if it has a knock sensor and normal dizzy set up?

Edited April 9, 2009 by dino20vt

[Anthony 1,000]

How is the timing changed (ie advanced/optimised) if it has a knock sensor and normal dizzy set up?

You're confusing a distributor with a distributor cap/arm.

 

All a dizzy cap and arm does is point the spark towards the correct cylinder. An Mi16 does not have a distributor, and ignition timing is set by the ECU.

[dino20vt 3]

Im with you now, I didnt realise a 16v just had a cap, whereas an 8v valve has a distributor which can be manually twisted to alter the timing as well as the vacuum to alter it whilst running, a 16v is controlled by the ECU? What about 2 row without a knock sensor?

Edited April 9, 2009 by dino20vt

[Anthony 1,000]

Im with you now, I didnt realise a 16v just had a cap, whereas an 8v valve has a distributor which can be manually twisted to alter the timing as well as the vacuum to alter it whilst running, a 16v is controlled by the ECU? What about 2 row without a knock sensor?

All 1.9 Mi16's have proper ECU controlled ignition timing

[dino20vt 3]

So the idea of a knock sensor is similar to that of bob weights and vacuum advance on an 8v?

[Anthony 1,000]

So the idea of a knock sensor is similar to that of bob weights and vacuum advance on an 8v?

No, a knock sensor detects knock (pinking) and retards ignition timing to prevent engine damage.

 

The function of the bob weights (advancing ignition with engine speed) and vacuum advance (advancing ignition under part-load / cruise conditions) is controlled by the ECU based on the ignition advance map. The ECU takes input from a number of sensors - e.g. crank sensor (rpm), AFM (load) - and referencing that map, fires the coil to give the correct amount of advance.

[d-9 0]

So the ecu doesnt have bob weights in it?

[dino20vt 3]

No, a knock sensor detects knock (pinking) and retards ignition timing to prevent engine damage.

 

The function of the bob weights (advancing ignition with engine speed) and vacuum advance (advancing ignition under part-load / cruise conditions) is controlled by the ECU based on the ignition advance map. The ECU takes input from a number of sensors - e.g. crank sensor (rpm), AFM (load) - and referencing that map, fires the coil to give the correct amount of advance.

 

But if it has no knock sensor, what tells the ECU to stop advancing the ignition?

[Anthony 1,000]

The amount of advance for a given engine speed and load is pre-determined. For example, the full load (WOT) map might look something like:

 

2000rpm = 20 degrees

3000rpm = 25 degrees

4000rpm = 30 degrees

5000rpm = 32 degrees

6000rpm = 30 degrees

 

The knock sensor is quite primative and is only reactive - ie it can only reduce advance for the pre-determined amount. It's there mostly to protect the engine for example if you have a bad tank of petrol that's low octane, and would other pink and potentially damage the engine. On a primative system like an Mi, the knock sensor doesn't gain you any power.

 

In the above example, at 6000rpm the ECU would fire the coil at 30 degrees BTDC, and on a good tank of petrol the knock sensor does nothing, so it carries on with 30 degrees advance. However, you do the same again with a bad tank of petrol, and when the ECU fires the coil at 30 degrees BTDC, the knock sensor detects pinking, and the ECU retards the timing until the knock sensor no longer detects pinking, which might be say 28 degrees.

 

Make sense?

 

Might be worth having a look on something like Howthingswork.com and seeing what it has to say about ECU's and ignition timing on there, as it's bound to explain it better than me.

[dino20vt 3]

No it all makes total sense mate, cheers, I get it now! Basically a 2 row without a knock sensor will just pink. Am I right in thinking more modern ECU's are adaptive and learn what fuel you use so the knock sensor is also used to improve performance?

 

 

So:

 

2000rpm = 20 degrees

3000rpm = 25 degrees

4000rpm = 30 degrees

5000rpm = 32 degrees

6000rpm = 30 degrees

 

are hypothetically programmed onto the ECU from the factory or when the ECU is reset (like I did on my Fiat Coupe) but the advance values are upped and upped till pinking is detectected then knocked back slightly so optimising performance?

[welshpug 1,627]

on the old Mi16's its pre-set, on the later 2.0 they self learn to an extent

[DrSarty 90 1 Cars]

Saying a knock sensor 'improves performance' is probably not a very clear way to put it.

 

It's a measure to try and prevent something detrimental from happening, rather than making something which happens normally happen better.

[BackStreetRacecars 3]

Presence of a knock sensor and a lambda mean that the settings for fuelling and ignition are at their optimum working tolerances, It being a closed loop system meaning it can always adjust fuelling and ign to suit engine load and rpm... Whereas dizzy/rotor arm- non lambda and knock sensor systems are open loop- meaning their settings for rpm etc are set values...... maybe I'm just reiterating other peoples points... but I wanted to be included!!!!