acquired a megajolt set up for a mate to fit on a zetec engine he's planning on running 45's on.

cut a long argument short he's saying he doesn't need a throttle position sensor i'm saying he does.

surely to make use of it's mapping it needs to know where the throttle is relative to the rpm etc?

if i'm wrong i'm not fussed i'll happily be corrected but he was being smug about it so i'm hoping i prove him wrong!



cheers
john

To get the best out of the megajolt it needs a TPS to indicate engine load to create a 3d map.
Without one it will be possible to run but only on a rev based 2d map, which wont give the same throttle response and driveability
Paul.

I have just started looking into megajolt, which I plan to fit onto a brand new 2.0l Zetec. Looking at the website, Version 3.0 of MJLJ is now available, and you are now able to build with either a TP Sensor, or an internal MAP sensor. Im not sure what this is lol, but That might be why he's saying he doesnt need a TPS?? While theres a convo open regarding Megajolt can someone confirm for me that this will work with my engine?

IIRC Megajolt v3 requires either a MAP sensor or a TPS. v1 and v2 only had MAP. You can't use both so it's 2d only. TPS components are cheaper and easier to get than a MAP sensor.

See:
http://www.picasso.org/mjlj/?q=node/500
for details.

TPS for performance, MAP for fuel economy is a rule of thumb I've heard for ECU's.

On webers I presume fuel economy isn't his first concern so you can probably call it an honorable draw

p.s. I've seen them on Zetecs
p.p.s MAP is a Manifold Absolute Pressure sensor i.e the big oval-ish plastic component. Which needs a tube to the inlet manifold. It does the same job as the vacuum tube does mechanically on a distributor.



[Edited on 30/8/06 by iank]

Megajolt is ideal for fitting to zetec , with either bike carbs or webers.
Map can be used with multicarbs but needs the vacuum lines pluming in correctly and a damper fitting , TPS is probably best for ease of fitting and set up.
Paul

Iv got megajolt on my zetec. Piece of pee to get up and running. Im using bike carbs and iv made a bracket to connect the TPS to the throttle linkage. TPS is much easier to set up for multicarb'd engine, For a map sensor youl need some sort of swirl pot to even out the vacuum from the 4 ports.

For a pair of DCOE's you really need a Throttle Position Sensor (TPS) to indicate engine load. You can rig up a MAP sensor, but it's a load of hassle for not much return. On a single carb system a MAP sensor makes much more sense.

As said, you could run MJLJ without any engine load sensor, this would be equivalent to running a distributor with no vacuum advance, but there really seems little point in doing this. Part throttle economy and driveability will suffer in the same way it does with no vacuum advance.