Hi,
I am looking at building one of these to fit to my MK2 ford fiesta 2.0 zetec conversion using the standard ford injection.
I`m not exactly sure what version I have to build to run the mjlj on this engine setup, any pointers ? im a bit confused with the map sensor / tps options etc..
ta
Newbie Q`s :)
Moderators: JeffC, rdoherty, stieg, brentp
The current version of MJLJ
The current version of MJLJ is 3.0
MJLJ will do a 2-D ignition map - advance vs RPM only
MJLJ will do a 3-D ignition map - advance vs RPM and MAP
MJLJ will do a 3-D ignition map - advance vs RPM and TPS
You can't have a 4-D MAP (advance vs RPM and TPS and MAP) !
If you want 2-D, you don't populate the TPS or MAP sections of the PCB
If you want 3-D TPS, you populate the TPS section of the PCB, supply and fit a TPS on the throttle actuator and wire it to the MJLJ connector
If you want 3-D MAP, you populate the MAP section of the PCB (including the MAP sensor itself), supply and fit a vacuum pipe from, typically, the manifold to the MAP sensor inside the MJLJ case.
For the MAP and TPS sections of the PCB, see the last but one link on the following (but note there is no picture of a populated TPS section):
http://picasso.org/mjlj/?q=node/495
MJLJ will do a 2-D ignition map - advance vs RPM only
MJLJ will do a 3-D ignition map - advance vs RPM and MAP
MJLJ will do a 3-D ignition map - advance vs RPM and TPS
You can't have a 4-D MAP (advance vs RPM and TPS and MAP) !
If you want 2-D, you don't populate the TPS or MAP sections of the PCB
If you want 3-D TPS, you populate the TPS section of the PCB, supply and fit a TPS on the throttle actuator and wire it to the MJLJ connector
If you want 3-D MAP, you populate the MAP section of the PCB (including the MAP sensor itself), supply and fit a vacuum pipe from, typically, the manifold to the MAP sensor inside the MJLJ case.
For the MAP and TPS sections of the PCB, see the last but one link on the following (but note there is no picture of a populated TPS section):
http://picasso.org/mjlj/?q=node/495
Thankyou for the reply, Just
Thankyou for the reply, Just one question tho...
MJLJ will do a 3-D ignition map - advance vs RPM and MAP
MJLJ will do a 3-D ignition map - advance vs RPM and TPS
Is there any advatage or difference in using MAP or TPS ? or do I need a specific one for my engine setup ?
thanks
MJLJ will do a 3-D ignition map - advance vs RPM and MAP
MJLJ will do a 3-D ignition map - advance vs RPM and TPS
Is there any advatage or difference in using MAP or TPS ? or do I need a specific one for my engine setup ?
thanks
Well, it seems to be a
Well, it seems to be a matter of some debate which is best, IMHO.
Traditionally, manifold vacuum is used, which is why 'old fashioned' ignition systems had a vacuum advance ie a pipe from inlet manifold to distributor to advance the timing when there is more of a vacuum in the manifold.
On more modern engines, there is not always a good take off point for a vacuum, so throttle position is used to advance the timing - driver pushes throttle, therefore is requiring more engine power, so advance is increased to assist this.
I'd say (my $0.02) that if you have a good point to take off a vacuum (which is an average across all cylinders, rather than say a single throttle body), then use MAP. Otherwise TPS.
Traditionally, manifold vacuum is used, which is why 'old fashioned' ignition systems had a vacuum advance ie a pipe from inlet manifold to distributor to advance the timing when there is more of a vacuum in the manifold.
On more modern engines, there is not always a good take off point for a vacuum, so throttle position is used to advance the timing - driver pushes throttle, therefore is requiring more engine power, so advance is increased to assist this.
I'd say (my $0.02) that if you have a good point to take off a vacuum (which is an average across all cylinders, rather than say a single throttle body), then use MAP. Otherwise TPS.
MAP
I would say go with a MAP sensor based setup as it's a more accurate way of measuring actual engine "load".
Unless you have very aggressive cams that prevent a stable vacuum reading, then you should go TPS.
Also- individual throttle bodies require a mini-plenum in order to attain a good MAP sensor reading, additional work.
Turbocharged engines- I would *always* recommend MAP, as boost pressure can vary wildly for a given throttle position.
Brent
Unless you have very aggressive cams that prevent a stable vacuum reading, then you should go TPS.
Also- individual throttle bodies require a mini-plenum in order to attain a good MAP sensor reading, additional work.
Turbocharged engines- I would *always* recommend MAP, as boost pressure can vary wildly for a given throttle position.
Brent
Thank you for your replies,
Thank you for your replies, I now understand a lot more than I did 
As for the CPS, I take it I can use the existing one on the zetec ?
As for the CPS, I take it I can use the existing one on the zetec ?