Tom Harper

That makes sense about it coming out of the water, I never thought of that! No, I wouldn't call 11.5 too rich either (maybe a little) but i do like to tune a little leaner than most but with less timing. it makes similar power but with more room for error if something goes a bit wrong. But no, 11.5 isnt too rich really. But maybe something happened to cause it to go over rich? Looking at your map i notice there is no adjustment for iat's. I always like to pull timing after about 40degC on boost but it depends a lot on the setup, but with your temps varying by over 20deg on boost it would have been good to have some adjustment. Im sure you're aware that a hotter charge is less dense and therefore requires (theoretically) less fuel. this could have caused a rich condition out on the water, when compared with it on a dyno with possibly lower iats. It would only need to dip into the 10's before i would get concerned about the amount of fuel, and thats not too far from where you were. its difficult to say without more data tho obviously. Theres a few random peaks and troughs on that map though. It still seems like a lot of timing to me but then ive always been very conservative with that. but espescially with the 98 octane (RON?). but you're right, that should have showed as knock or deposition on the plugs and should have left pitting. I doubt it was anything to do with the charging issue, ive had these ecu's on cars with batteries that have gone flat many times, and just jumped them off or charged them and had no issues. I even put the charger on backwards once in the dark and got lots of sparks! no issues though, still runs fine. I did once fry an injector chip in a g4, down to a peice of electrical tape coming unstuck due to having been contaminated with petol causing a short circuit (should have used heatshrink!). This was instant and permanant though, the injector stuck open, it ran on three cylinders and dumped fuel in the exhaust for a few seconds while it was restarted. But the nice people at link were kind enough to point me in the right direction to find a replacement chip and its fine now. Since you have tested the ecu since the failure I doubt that it failed.

It still looks like a rich failure to me. The lack of pitting confirms this really. Pitting would show on lean detonation, but pre-ignition from being too rich would only show as melted edge. The theory behind it is that an overly rich mixture causes carbon buildup under the ring, which then lifts or pinches and causes oil to get by. this then massively lowers the octane rating of the fuel in that cylinder and then you end up with pistons like that. Ive got a honda engine (2.0) in my workshop now, that someone else tuned (lots of timing, lots of fuel) which looks exactly the same. ZERO pitting, even on the affected piston. just a melted edge, 1/4 of the way round and melted rings in the affected area. there was no shortage of fuel here either. Obviously it depends a lot on fuel used and compression ratio etc etc, but that log looks to me to be quite a lot of timing for what must be a small bore engine at moderate revs (correct me if im wrong, but im guessing its a bike engine or similar and not race fuel/meth). And the high iats wont have helped much. Also, why does the boost pressure fluctuate without any change in revs/tps? I think it may be that it was just pushed too far for too long, and no single component was to blame.

When a piston goes like that it tends to be pre-ignition rather than detonation (which would show as pitting throughout), and can often be a sign of a 'rich' failure, rather than a lean one. might help you ttrack it down.

Glad im not the only one having this problem. To be honest, the way we have taken one particular car now, anything up to 30 tables would be more like it. Or to put it a better way, each and every feature 'should' be able to be used at the same time, like most other ecu's out there. I feel this is the only thing holding back link from total market domination and would have thought it would be higher on your priorities list, but I understand you are more than busy. I really do think it would be in your best interest, even from a financial standpoint. We are making do for now and Ill still recommend your ecu's over all others but it would be nice have more functionality. The code to lookup the tables must be there, so surely its just the space taken up by the actual tables? I know I for one would gladly take, for instance, a substantial decrease in internal logging capacity. Say 50%? I know the old honda ecu's used to manage with just 256k, and they used to fit many tables onto that. 2mb would mean lots of room for tables, wouldn't it? I understand how each lookup section would need to be re-written though, i dont envy the task. But it would get you more supporters. Tom Future Racing Developments Ltd

More than 12 tables are required. On a link plus g3 upgraded to g4 the amount of tables (and therefore features) are reduced. This is a step backwards and Im starting to wonder if the upgrade was worth it. Surely its only a few 10s of Kb? 20 or even more would be more like it. On the car in question we are going to have to either delete anti-lag or individual cylinder 3d maps, where previously both could be ran simultaneously with more besides.

It would be nice to have more than just 2. Currently, if you have traction control (RPM or groundspeed versus slip) and oil pressure shutdown (oil pressure versus rpm) thats it. It would be nice to have another one or two for other things, safety features are always nice. AFR versus boost or water injection flow versus boost for example.

Hi, on this subject, I see MAF listed as well as MAP in the load axis selections for GP PWM outputs. Would it be possible to wire in a sensor with a 0-5v output into the MAF input and use this for controlling an output, and if so, where would you wire it in on a link plus g3? I dont see it on the diagrams (load input 2). Thanks, Tom.