yea, im ready to give up on this, i spoke to vince at stealth and got a much better reply, hes going to setup and remap mine for me but its 250. not sure the engines worth that. i was looking at the kent details on the site. did you set your cam at 110 degrees on the crank or did you just do yours at tdc? tsr site says this is fine for 1.8-2.1 so i cant see it being that. thanks again mate
who ever said check my alternator, i should of done it sooner but didnt think about it. maybe/maybe not the reason for my probloms, but it was giving out 17volts cold and 16volts when it warmed up. co 1.6 hc 2350 lambda 1.16
mike, i havnt swapped it yet, my mates got a spare alternator for me tomorrow so il try it out. was thinking it might be why i got 5.82volts on the idle swith plug instead of 5.v. but 17.03v at the battery and just over at the alternator cant be good for the sensors or injectors. altough i got it almost to a comfotable drive. i zeroed the pulley as advice from vince but the car felt flat as anything. so i advanced the cam a very very small amount as i was thinking to take up the retard from head skimming and such. and it seems abit better. ignoring the hc as im putting it down to overlap atm. what should i be aiming to get co and lambda wise with everything plugged in and idleing as ready to drive, i,e mot time. i think mine is sat at about 1.6 co and 1.18 lambda. am i right in thinking if i advance the ign timing lambda goes more rich whilst co stays the same? how much extra advance should i be able to get out of this saftly on 97/99 ron fuel? and itll go to vince once im sure everything is as it should be and just needs setting up. but i really want to go back to 2litre, or would love 2.1 before i go with remapping due to the price. is it worth remapping a digi? thanks guys
can any give a brief rundown on how the fuelling works on the digi, how does idle mixture effect the rest of the rev range etc. thanks
Agreed...Vince knows his stuff & your engine will definitely benefit from some RR time, rather than a screwdriver tweak here & there, & questions upon questions on here!. No offence intended It will be money well spent IMO
I'd think that the voltage regulator problem must be throwing out all the ECU readings from temp senders and the like. As for ignition timing vs lambda, I'd have thought there wasn't a direct relationship, but I'm willing to be educated otherwise!
I been reading too much. A dis ign engine book states a list of air feul, co and lamda and it says the figures would mean nothing without optimised ign timing. And if no one wants to answer my questions then feel free to look away. Id like to get any probloms sorted first cause vince is 100 miles away. And i wouldnt of been happy if i was told sort your alternator and come back. Thanks everyone for the help. Sorry i dont keep my questions simple
trouble is finding optimum without a dyno is v tricky. standard factory values get you somewhere close but only way to optimise for your particular setup is seat of pants testing. and this is a nightmare with mk2s due to position of dizzy. not so bad when dizzy is on end of camshaft as you can go for blast and keep pulling in making small changes to ign with easy reference to where you started. but with mk2s you really need timing gun to know how much advance youre adding which obviously isnt practical at side of road. sounds like your setup would def be worth a trip to stealth but like you say.. no point spending setting up a car with an underlying fault.. hopefully alt. will solve things
but then how does ecu know whether youre at 4k or 6k? always assumed afm controlled fueling right through rev range
right, if anyones interested. seems that putting my pb fpr and injectors on seems to have cured most of my jerky issues off idle upto 4200rpm,, just i cant seem to get the co down with the blue sensor disconnected so i set it to 2.4 co @ 1.1 lambda with the sensor connected. was bogging abit upto 2k but i had 95ron in, 50 v-power today, had a bit of spluttering coming onto the carrigway but then it cleared and seems much better. seems to be linier trough the rev range, i dont seem to feel when the cam comes in, should i? and are they riseing rate fprs on these or fixed? and... if i hadnt done all this asking questions, i wouldnt of got it running aswell as it does without asking on here, so thanks to everyone that helped me out. if i hadnt asked i would of drove 100 odd miles, to be told you got something wrong, i cant do anything with that, sort it out and bring it back. so thanks again. i know when somthing isnt right, its just hard to pin point it without knowing possible things to check. not many people around that know the mk2s well anymore, not around london anyway that i know of. so the forums been a great help. just like ukmkivs when i k04ed my mk4. the treads are still helping others, just like i do when i open my inbox to 4 emails asking what parts i finilly used to do it and i reply to them all..... sorry for the rant oh yea... thanks again
have you changed the sensor? there are plenty of people around your area, and there will always be people on here to make suggestions.
interesting.. so afm becomes redundant over 4k? wonder if holding it at 4k would allow you to calibrate afm ie setting to fully open at 4k should help airflow over 4k
if you set it as it VW intended (Rubjonny Digi setup) then its fine on a standard engine, once you start modifying it will require more fuel. mmost 2litre conversions work fine, but if you looked at AFR's it will be pretty lean.
so is it really a problom setting co without disconnecting the sensor? and would it be worth me going a cpl clicks back on the afm, im running rich low down but i guess id be running lean at the top?
OK. First of all you are changed the engine beyond the factory control settings by replacing the camshaft. You will have overlap which will hurt come MOT time as you will need more idle fuel, to keep the engine ticking over. Most of the idle fuel will end up out the exhuast which cause HCs and CO reads beyond the MOT thesholds for your model year. At WOT digifant is mapped lean with dip to slighty richer mixtures at 4K rpm then heading out lean again after. The spark tables held on the cache of the CPU and calibrated to match this with offsets from the knock system. At WOT the AFM load/speed calculation is offest richer and more retarded with a WOT switch. AFM load/engine speed table without the switch is used for after coming out of idle, partload up to the WOT switch activation. Idle load is via the idle switch which is the same input as the WOT. At idle your spark is retarded from base and your mixture is enriched from base. Further offsets to this mixture can be applied via the AFM bypass or by tweaking the flap spring tension. Unplugging the coolant temp and crossing the 3000rpm puts the engine in open loop mode to allow for basic fixed settings such as fixing the global spark table, CO mixture and idle speed. These settings where all the VW service techs needed to know in order to get any 1.8 digifant vehicle running as the VW intended. These specfic settings are not applicable when the engine is modified as in this case with an air path enhancer i.e. a camshaft. To enable improved, starting optimum pullaway, cruise and WOT performance, from an engine as yours, you may need to look to a SEM system else you would end up with more trouble than it is worth. In my opinion getting even a stock 2.0 with PB head and so on, to run on an ECU calibrated for a lower compression 1.8 is not the correct way of doing things. It will start and run the engine yes, but with the crude mixture curve ( and possible spark adjustment) just explained above I cannot see how this is optimum. Putting high performance components just makes control requirements greater, beyond the purpose of the factory ECU.
