manifold pressure sensor

[yankeedoodoo]

Continuing problems getting my pectel ecu correctly mapped. Some friends seem to think that without a manifold pressure sensor it can't really be a 3D system. When looking @ available systems it doesn't appear to me (an admitted mechanical dolt) that any system attempts to utilize that bit of data. 3D mapping and aftermarket ecu's are only just starting to be used here and it is my opinion that you lot are far ahead of US in this area (no need to enumerate other areas where you also exceed in this brief forum) and that my amigos may be mired in 2D or older, more crude injection systems as offered here. But, I am unable to refute their belief that that data is critical owing to the fact that I a mechanical simian. What am I, we or they missing in the thought process? I VERY much appreciate any light which can be shed upon my intellectual darkness. Thank you, lets have some pints in the future: your land or mine!

 

[oilyhands]

There are three common ways to assess load on the engine (the third dimension of 3D), manifold absolute pressure , airflow metering/sensing and throttle position. Many after market systems simply use throttle position via a throttle position potentiometer and assume that for any given throttle position at a particular engine speed the airflow will be the same; this is probably a fair assumption. Other systems which use MAP or AF use the throttle position data for identifying transients such as acceleration and deceleration.

 

Try here for fuller explanation.

 

Oily

[AMMO]

Yankeedoodoo

 

The fuel injection systems I am most familiar with are the Weber Marelli ones fitted to motorcyles. These are a bit old hat now as they are Eprom driven but were ahead of their time and still give very good service. Used on Ducati superbikes to win quite a few AMA, World and British Superbike championships in the past. Also used on a quite a few road bikes and a was originally a car ECU that was adapted to bikes. They run very sweetly if correctly set up. These rely on a throttle position sensor to establish if you are on the gas or not, or indeed how fully open the throttle is. Depending on revs and throttle opening your ignition timing varies quite a lot. The problem you are having may be due to the fact that the ignition map is not correct. Anyone can set the fuelling based on CO or Lambda readings but fully understanding the ignition requirements is another matter. Some of your bad fuel consumption problems may be due to the ignition timing not being advanced enough on the overrun. It is not abnormal to see figure of 50 to 60 degrees advance. Also if the ignition at low rpm is not correctly set you will need more fuel than neccessary to stop the engine stalling.

 

In my opinion if you have a throttle position sensor you do not need a MAP sensor. An atmospheric pressure sensor is essential for good running at high altitude. I think the Pectel T2 has this built in to the ECU (should have a small hole in the casing). Are you anywhere near mountains? Is the so-called "adder" for atmospheric pressure enabled? This will add or remove fuel dependant on atmospheric pressure. If you go up and down mountains funny things can happen. I know this from supplying Eproms for Ducatis to customers in California that didn't have this facility enabled from the factory.

 

Hope you get it sorted. You have a good piece of kit. Just need someone to set it up for you. I don't think you would have any less problems with another brand quite honestly. These things are only as good as the people that work on them.

 

 

AMMO