Hi Here I am with another question. I have a 91 mk2 with 1.8 digi head, 2.0 bottom, 4 branch manifold and 268 camshaft. does the sport camshaft change the way timing should be set? I have a strobe lamp, do I still put the timing on the mark? last time I tried it, it ran very rough so I advanced it "by ear" untill it ran smoother, but now I have pinking with light throttle. besides that the car pulls great, the spark plugs are very clean. [edit] don't know if it matters, but the car starts a bit hard, it turns about 6-7 times and sometimes the engine surges for a couple of minutes when idle (mostly when cold)
I would set the timing properly. Remeber to disconnect the blue plug and block the pipe out of the isv with a screwdriver or something. The car then needs to be revved past 2250rpm three times (can't remember why but to do with ECU). The correct setup procedure is on here somewhere and its important nothing is left out so have a read incase i've forgot. Once you've done that I'd advance it slightly be ear like you have. If it's pinking you should be using as high an octane fuel as you can (especially as they should run on 98RON anyway)
'It depends' Your engine will need a bit more fuel than a standard one, so what have you done to give it more fuelling? It should run on standard ignition timing, but if it's not getting enough fuel, you won't get the most out of it. As said above, you want to run it on decent spec fuel too, rather than standard unleaded.
I am only using 98-99 octane fuel, and yes I know the procedure for setting the timing. as far as I remember, before installing the sport cam the engine started very easy (about 1-2 turns) but still I am not convinced this has to do with the cam. the story is a bit longer: I had some problems with the last 2E block (some inside knocking) and swapped it with another one with less mileage, and also rebuilt the gearbox. when I put it all back together, I also installed a 268 camshaft and put all the timing marks to line up. engine started the first time and had to slightly adjust the dizzy to sound ok. can "playing" with the afm lead to pinging? I did my mot about a month ago, and the guys there wanted to adjust the CO reading, but they could not get it lower than 5 (normal should be about 1.8) and when I left the garage the car was running like crap (too lean I guess) so I turned the afm screw clockwise to about it's original position, then the car worked better.
On a std engine leave the ign timing std, on a mine with a gs1h cam i was advised to set it a few more degrees advanced 7-8ish. worked just fine for me suck it n see, but remember you cant tune it 'by ear' with the digi managment it has to be done the proper way, see my digi tuning guide.
If your CO2 wont go down past that with the hex bolt all the way in the AFM is probably due for swapping. I wouldn't think this could cause pinking as this is primarily an ignition timing issue, usually you retard timing to stop pinking.
These are the problems you get when you replace the engine with a larger capacity unit and update the camshaft to one that could increase volumetric efficiency at different to stock load/rpm conditions, when still using the controls for std 1.8 engine. Haynes setting procedure does not apply!!!! I had similar issues when my 8v engine was updated to a 2litre. Having analyzed the STD fueling curves from the digifant ECU, the conclusion was they were quite shocking. It was also observed that 2litre 8v conversions seem to have more static compression that 1.8 units. This influences the where the dizzy must be initially set for starts, which in turn makes running performance sluggish. With the dizzy set where the vehicle feels a bit more lively (resulting in crap start), you may find that there may be slight det at 2-3K rpm and sometimes at 5k. Chips make the fueling slightly richer at certain points but generally overall AFR control is still not acceptable. The poor lean AFR at certain points in the rpm sweep at WOT, may influence the detonation as explained above. For MOT my CO was a tad higher than when running the PB engine and I am sure yours would become worse due to increased idle fuelling to suit the overlap in your camshaft. It is for these reasons digifant was junked on my case and I switched to a standalone. Now my car can pull-away from 15mph in 5th gear with no detonation, Pass the MOT without fiddling with idle fuelling and accelerate from a standing start to 60mph in about 7.5secs. All from a STD 2.0 8v.
I've been in that car ^^ and I have to say that for a 'standard' 2.0 8v it's superb - Pulls really well from low down, all the way up, and revs over 6k no problems. If you need an immediate 'solution', backing off the timing a smidge might help the starting (although it could be a combination of a tired starter and a higher compression engine) and reduce the pinking, but you probably want to get your knock sensor checked too. After that, you either need to get the car on a rolling road, or use a wideband AFR meter to see where it's running rich or lean. You can't do much about the ignition side without going for megasquirt, or other standalone management, but you if it's running lean, then an increase in fuel pressure (changing the regulator on the end of the fuel rail) should help. I've been told that squeezing the standard regulator in a vice can up its pressure, but I've never tried it myself. You'd need to do it between two sockets, to protect the pipes, I'd think.
Another solution for starting is to obtain a MK3 8v starter as these are gear reduction units and output more starting torque. I did this to my 2.0 8v to allow me to run more global ignition advance when on digi.
the knock sensor is a new hella one, I got it last year and was bolted in at 20 Nm with a torque wrench, my guess is there are no problems there. could an adjustable camshaft sprocket help in any way? maybe I need finer tuning than the dizzy can offer. I am planning in the near future to get the TT digifant chip, maybe some thins will change then. i'll be back with updates. so what conclusion do we have in the end? that swapping a 1.8 block for a 2.0 with digifant injection is not such a good ideea? I also have a 2.0 head laying around, will that change the way I can set the engine up (I am reffering to the part with the static compresion and the fuelling problem)
mine ran just fine, but I guess a GS1H cam isnt as lairy as a 268? Not sure on the specs. I also fitted some vaux creme injectors, from a 2.0. only mildly uprated over std but seemed to work well. main reason i fitted em was they were nearly new, not because I knew exactly what I was doing
Sounds like you followed the correct procedure for fastening the knock sensor. But this does not change the mapped parameters for spark. May help detection if it is not doing so already. Adjustable cam gear would influence torque curve, but it still cannot cure mapped fueling requirements. American TT chip is calibrated for rubbish US spec fuel, not really "good" EU blends. It may address the some typical AFR holes found in a WOT sweep of a digifant II controlled engine but it still will need to address the spark tables calibrated a smaller engine with less compression dynamically. And engine that works "fine" to some may not mean that it is running optimum and I am still yet to see an STD engine 8v 2.0 conversion in a MK2 on digifant accelerate to 60 in 7.5secs and return 37mpg. A performance 268 camshaft in your application requires tailored control of fuel and spark angle if the engine is to output torque as it should. If you cannot achieve this level of control then in my opinion you are wasting time with desktop calibrated chips or worse yet OE control modules for totally different engines.
the 268 camshaft is also from Techtonics. if I get the TT chip, the worst case scenario is that I would have to get an US spec ecu, from what I understand. meanwhile I tried more adjusting and it seems to work a little better (less pinging) better idle but still it starts like sh*t when cold. when it's up to temp, if I shut it down and start it up again it goes instant. about the mpg... I can get it up to 35-40 on the motorway, in 5'th gear with 70-80 mph
