Motronic For The 1.6

[Terry1600 14]

pretty fed up with the constant faffing with the jetronic on my 1.6, its never right, is there a motronic setup that can be used on the 1.6 XU or is it a case of switching to DTA or Omex?

 

Cheers

[welshpug 1,661]

you could use the system from a 1.9 and get it mapped, 106 used mp3.1 on a 1.6 8v tu iirc, though im not sure if that could be made to work easily

Edited October 20, 2017 by welshpug

[Leslie green 111]

Would be cheaper to fix whatever isn't right on your own car and get it running right .

[Terry1600 14]

seems like its not getting enougth air when its cold, wont automatically hold a high idlle and then come down when warm, it holds a cold idle if i am gentle with it then when it heats up its goes up high, total opposite of what its supposed to do

[Leslie green 111]

I dunno how to fix it Terry but a lot of issues are caused by air leaks in old hoses like the sad valve ones etc which are now 25 years old if original and dirt in the throttle body stopping it closing properly etc ,there is a setup procedure in the haynes for setting the idle etc .maybe you have tried it already but it will only work if timing etc is right and no air leaks . Mine wouldnt idle and there was a bolt missing of the side of the inlet to hold the oil filler up leaning the mix among other things .

[DamirGTI 342]

Sounds like the SAD heater doesn't work , missing 12v feed or ground .. without the heater working it will not close the bimetallic disc in the SAD thus making high idling warm engine .

 

D

[Terry1600 14]

thats what i was thinking, so i tried blowing down the sad pipe when its cold and its open, i wait untill it warms up and i take the sad pipe off again and its closed.

[Gaz205 50]

seems like its not getting enougth air when its cold, wont automatically hold a high idlle and then come down when warm, it holds a cold idle if i am gentle with it then when it heats up its goes up high, total opposite of what its supposed to do

What rpm do you call high?

[Terry1600 14]

it will idle at between 800 and 1k, after a couple miles it will hold 2k, if i turn it down a bit on the idle screw back to 1k it wont hold anything when cold, have to turn it back up to hold 1 when cold where it will go back to 2 again

[Miles 331 1 Cars]

Block the SAD off for a test, Just means until warm you need some throttle, Wiring in another system unless you know what your doing is not cheap

[DamirGTI 342]

Go for a 15-20min spin , warm up the engine fully , when the idle peaks stop and with the engine running pinch the SAD hose going on the main AFM to TB air hose and hold pinched for a while with the engine running and listen - if the idle speed drops down it's the SAD not closing and need wiring fix in most cases . If it makes no difference SAD is ok. , closing , and it might just need cleaning and maybe an little adjustment for the cold starts (theres an 7mm nut at the back of the SAD , by slacking the nut you can move the SAD disc left or right making air bypass aperture bigger or smaller = more or less air at cold start thus higher or lower pre warm idle speed)

 

Had the similar issue in the past , it was the SAD not closing completely because wiring to the SAD heater element lacked 12v feed , just fixed the wiring .

SAD unit is mounted on the cooling system housing and uses both coolant temp. and heater element and needs both to fully close after warm up period .

 

 

 

D

 

edit : beaten by Miles !

Edited October 20, 2017 by DamirGTI

[Gaz205 50]

I think I have the same issue... Holds low revs when cold and starts fine around 1k but when warm holds 1400-1500 but my idle screw is fully in however the car runs and pulls fine, sad pipe test shows a slight drop in rpm. A timing adjustment did lower my warm idle speed at the loss of a clean pull through the Rev range. I replaced the Afm with no change, had the 02 mixture set up and no change to idle speed but improved drive ability. The common suggestions are un metered air flow and failed sad. Have you had your timing and Air / fuel mixture set up ?

[DamirGTI 342]

Ignition is , what makes the Jetronic system suck in most cases if you ask me ! fixing the ignition on Jetronic will make an nicely rock stable idle engine , just like Motronic one or similar ECU controlled system .

 

It's the dizzy , often the springs are off they're best after all these years and need just a little tweak (tensioning) and timing adjusting later (preferably by ear on the road) . Providing that the fueling side is OK and with all matching components , that the induction system is sealed with no leaks , ignition el. components in good working order , and engine mechanically sound .. if you still have unstable idle with all these checked and verified as OK. , try this with the dizzy to get stable idle (scroll down) :

 

http://forum.205gtidrivers.com/index.php?showtopic=169941&hl=

 

D

[Terry1600 14]

i need to fit another vacumme advance on it tonight as its just plugged for now as its leaking, ill give that a shot later and report back, cheers!

[Terry1600 14]

@ Miles, normally i get rid of the 8v after a week or two and fit gti-6 as whenever i get an 8v its always got issues. dont really want to change the engine as its clean and i cant be doing with the hassle. also i dont really want to be taking this one out to fit a trigger flywheel to run aftermarket ecu and all the other things it needs to fit a coilpack ect, trying to save effort and time but at this rate i feel like im going the long way around!

[petert 589]

I've done an aftermarket ecu conversion on a Jetronic using the dizzy as a trigger. It just requires removing/locking the advance mechanism and rotating the reluctor pins so they fire at approx. 70 deg BTDC, to avoid rotor phasing issues. Also removed the AFM flap. It then looks totally stock but has all the advantages of a modern ecu.

[Miles 331 1 Cars]

You can fit the Golf 16v Dizzy for a signal as well, direct fit