John McM

Found it by tapping the SXT button. I like the auto map function with the wide band sensor. It sounds like a task for tomorrow, then I can remove the sensor.

robt964

Auto map does not equal maximum power :-)
Often engines like a little more fuelling in the high rpm high load sites.

John McM

I thought it only mapped to 4,000 rpm. I'll check again. I like the idea of an interim optimized map until I get to a dyno.

robt964

>I thought it only mapped to 4,000 rpm

That would be rubbish. Nope it does the full range

John McM

I've just completed a 2,000km road trip through fast winding roads. I'm getting significant popping and banging with occasional flames out the back (according to cars following me). Before I do any mucking around with the ECU map I'm going to check the throttle travel to make sure the ECU is getting an appropriate signal. Possibly its telling the ECU its more depressed than I think it is. I did do a lazy fix on the idle microswitch when the mechanic returned the car and that may be upsetting it. The fun never ends.

robt964

"Possibly its telling the ECU its more depressed than I think it is"

What do you mean by this? The ECU only sees the throttle at idle and WOT. The rest is driven by the MAP sensor.

I'm assuming the popping/banging is only on overrun?

John McM

I didn't realise the ECU only sees the throttle at idle and WOT.

Yes it's the overrun, particularly at revs above 3,000. It's going to blow out my secondary exhaust and burn my new paint at this rate. Is there anything I can adjust for the overrun?

alexjc4

Sounds like you've not got overun fuel cut enabled.

John McM

ECU has a number of parameters but I can't see an on/off toggle. The parameters are TPS % on and off (both set at 78%), rpm on/off (set at 2,300 and 2,500 RPM) and delay of 200ms.

I see Robts map has the same settings. If the system doesn't use TPS then there's really nothing that appears to need adjustment here. This may be the nail in the coffin for this system unless there's something I have missed. I have no interest in burning the bumper on my new glass out respray.

Anthony Hutt

Still having issues with my spc. Will need to spend further $$ for a rollin dyno tune. Its running too rich and pops thru the gears under moderate acceleration. Its also jittery in the 1900-2200rpm range in 4th &5th. Noticed a cloud of blue smoke when starting up following a 15 minute stop after a 30 minute run up the freeway. Bumper also covered in soot .

John McM

Anthony, I get no popping under acceleration, just on overrun.

Please keep us up to date with what you find on the dyno.

For me this is the end of this current install.

I no longer frequent the track as often as I did and my other C4 is a joy to drive on a standard ECU in a more normal rev range. That plus I followed a normal ECU car for 2,000km on a road trip and he barely had a smudge of soot. My car looked like it was a diesel.

Enough is enough. As I have said before IMHO this is not a turn key solution for a standard 964. I have already spent enough time on it, know my AFR is ok, but where to go to next and to what gain? The popping and sooty exhaust are not normal.

I will run it one more time at the track and see if I have a perceptible performance advantage over a normal ECU. Unless it's demonstrated to kick butt it will go on the shelf.

John McM

Better exhaust pic. Btw the ducktail dirt is an oil leak not the system. A car following me said I had flashes of flame on the overrun.

evoderby

Hi John,

Really impressed with you fitting the kit and having a running engine within a 5 hour time frame. Sorry to see the lengths you have to go through to get the i's dotted and t's crossed after the initial euphoria of having a running engine and rock solid idle....the very basic nature of the SC manual and lack of hotline support not being a great help in that respect.

On the subject of your rear bumper being covered in soot: one thing that strikes me is you mentioning running 0.8 lambda at idle running towards 0.95 @ 3500 rpm. A lambda value of 0.8 or 11.75 AFR is turbo wide open throttle territory at best, dumping loads of fuel to cool matters.

I see really no point in the above on an NA car, especially at idle, as all it leads to is bore wash and sooty exhaust gas/poor emissions. I'd aim for lambda 1 or 14.7 AFR from idle throughout the medium throttle / high vacuum rev range, and something like 0.87 lambda or 12.8 AFR at wide open throttle.

The above are generic guidelines. Experience in tuning these engines might improve running characteristics by diverting from these values by the odd %. You say you fitted a Steve Wong chip in the past, perhaps you could use this in a Motronic equipped 964 and perform some wideband data monitoring at different revs / loads to get a benchmark to map against. Be it in closed loop mode, or you behind the keyboard.

That is, unless you have an experienced dyno operator at hand who really knows how to get the most out of our aircooled engines. And even then I would expect some on road testing / adjustments to be made to optimise transitions, dail out hicups etc. to perfect things.

This is exactly the problem with mappable Ecu's, there are many many ways to get things wrong. The not exactly intuitive menu structure of the SC computer not helping things here for the unitiated.

I do think you've come a long way and it would be a shame to terminate the project at this moment in time without doing some proper closed loop auto tuning based on solid AFR figures to aim for. And as a next step work on the overrun/flame spitting situation from there, which should be a simple fix once the proper table to set temporary injector shut off has been identified.

Good luck!

John McM

A local 993 owner installed a G4 Link system a few years back and said he spent a lot of dyno time getting it to work properly.

I didn't want the same experience and that was the idea of buying an off the shelf mapped ECU where the manufacturer controls the injectors, map sensor choice etc.

When that didn't work as hoped I thought that Robt's map would give a better result but his settings are not that dissimilar to mine.

I appreciate the motivation to continue but my continued preference is to apply a known working map on what is a standard engine than spend $$$ on dyno time. Reversing all of this will take an afternoon. I'll pass the batten to others in the hope someone will have a breakthrough.

evoderby

Ok, I did some quick digging on past threads. Geoffrey (9m's North American partner who does the 9m motec conversions over there) comments on the 964 naturally aspirated engines making most power at lambda 0.88 or 12.9 AFR.

He also mentions that a stock chip on a stock engine is richest at max torque to gradually lean out in the mid 13's towards redline.

Since a standard narrow band lambda sensor is only capable of providing reading very close to lambda 1, it is not surprising that in closed loop mode (anything but WOT) the motronic aims to establish 14.7 AFR from idle all the way throug the rev range at part throttle.

I'll state again, running 0.8 lambda at idle is rediculously rich!!!!

I understand the disappointment of the map supplied not performing close to optimum. Given the fact that Rob's map is performing well on his engine and is quite similar to your's maybe there's another problem like a faulty temp sensor causing the Ecu to constantly run cold start enrichment, perhaps the vacuum line to your fuel pressure regulator is split/blocked causing overfueling.

All stuff that reverting back to motronic won't rectify in itself.

I guess when you've had it you've had it and no words anyone else can say will change your mind. Best of luck!