Hi All,

First posting. Have done some Googling re MBE ecu's & a lot of links point me to Locostbuilders so I'm hoping someone here can help me make sense of some MBE ecu configs.

My area is IT/Computer support but have a good mechanical knowledge. My buddy has 2 rally cars, one running a 2L Ford with a MBE 967ECU & the other has a Toyota 1.6 4AGE with a MBE 956E ECU both running on twin 40 Webers. He asked me to take a look at the ECU configs as he has some timing issues with both. Both are fairly basic set up with crankshaft sensor, coil, shift light & rev limiter. There is no TPS on either. I've taken a copy of both configs & just trying to get my head around them on the laptop.

Ford first - With no TPS in play, I reckon only one SITE on the ecu is in used for ignition advance. Showing him the graph, it looks like the last site, site 15, has the correct advance for all the rev range. Delving deeper, I see that the TPS voltage is set to Min 5V & Max 5V which leads be to believe that is is just using the last site (15). Does this sound correct?.

On the Toyota, again no TPS, but the Min is set to 0.49 & max to 0.71. Not sure what site is in use here but the first one, 00, looks like the most likely.

Both cars are running fine so no need to do a whole lot just maybe a few timing tweaks. Just trying to get my head around this setup.

Thanks in advance,

Tim
Ford first

If there's no tps fitted, you need to look at the throttle upper/lower limits and upper/lower defaults.

So for example you may have settings of lower limit 0v2, upper limit 4v7, and the upper/lower defaults are normaly set the same for example 4v3. With no tps connected it will be outside the limits so will then use the default value. Cross reference this value to the throttle index map for the site number(row on the tps v speed ignition map). Normally that would be 15, but not always!.

The values you've found of 0v49 and 0v71 are probably the tps idle setting values and aren't used if there's no tps fitted.

Ian

Hi Ian,

Many thanks for your comprehensive reply. That makes perfect sense on the 967ecu in the Ford. Can't remember the exact figure but upper limit is about 4.8 so I guess it would then use the last site 15.

On the other 956 ecu, I'm still a bit confused. Upper & lower limits are the same on both ecu's but on this one, it's definitely using site 0 as by adjusting the advance on this site causes the engine to pop back thru' the carbs. Basically, the 2 ecu's have the same upper & lower limits but the 967 is using site 15 & the 956 is using site 0.

Thanks,

Tim

The upper and lower limits are the fault levels, if outside these values then the ecu uses the default value. With no tps fitted then the value set in the lower default setting is substituted for the tps value.

You need to look at the lower default value, not the lower limit.

It's quite possible that site 0 is being used with no tps fitted, but it would normaly be 15.

If you've pulled the chipfiles from the ecu's, e-mail them to me and it'll only take a few seconds to tell you what's what.

ian at oddified dot freeserve dot co dot uk

Ian

Many thanks, Ian. E-mail sent.

Tim

Thanks Ian for all the comprehensive details you sent me.

You're a genius.

Tim