5 replies to this topic

[jackmason]

Ok, so for some time ive had Megajolt installed on my car and its brilliant, it really is!
 
Initially i connected up the MAP (Manifold Air Pressure) sensor up the inlets to give me the load reading so i could adjust the ignition map. I then had the car dynoed and apparently due to the Camshaft (Kent 276) and the length of the inlets (6in) it wasn't getting an accurate readings so they put a 2D Map on it.
 
The cars been fine with this map for ages but the entire time ive used it, ive always thought. "Im sure i could get a bit more economy and drive-ability out of this"
 
So ive decided to connect a TPS (Throttle position sensor) to the weber, wire it into the megajolt and see if it helps.
 
Ive spent some time looking into this on various forums searching "Fitting a TPS to weber".
 
You can buy a TPS Kit specifically designed for the Weber but at £60-80 for a TPS and some brackets i thought ide give it ago myself.
 
My friend rick has donated his MPI TPS  but it means i need to try and fit it to the carb the same side as the throttle linkage making things tricky.
 
Getting the TPS to fit
The spindle on the MPI thottle body is 8mm, with a flat on the end. The Weber spindle is (Acording to one website) 7mm with a 1mm pitch. Ive measured the pitch and can confirm that, but are yet to find the correct thread size as the 7mmx1 Die i borrowed didnt fit onto the spindle end.
 
Anyway, ive had my friend turn this adapter up

 

At the moment it doesnt have the flat on the end as i need to tighten it onto the spindle then mark where to grind the flat.

 

I originally thought the spindle has a 1/4 UNF thread so the adapter was tapped to that but im wrong and am trying to find the correct size.

 

Anyway, here are some photos of my carb.

 

Green dot and arrow = Positions which the TPS bracket will attach to

Red Arrow = Nut on end of spindle which the adapter will replace

 

Yes it very dirty and for some reason im always getting the fuel leaking out the filter end of the carb.

 

This is roughly where the TPS will sit once fitted

 

Will try to update this when ive done more work, its also on the Essex Mini Club forum which will be the most up-to-date as im always on there

[jackmason]

Got it all sorted last night.

 

Most of the work was done by my friend dave

Tapped the adapter out with an M7x1 Tap, It still didnt fit onto the spindle properly but went on enough to tighten.

 

I also noticed that i wasnt getting full throttle. This shows the cause of the problem. (Circled red) I needed to take the edge back to the green line.

 

 

 

Dave made my the bracket up and with some tweaking we got it fitted without it fouling on the linkage.

 

Also made up a loom which is about 3 times as long as i needed, but it works so i will shorten it when i get a plug for the TPS

 

[jackmason]

Saturday i decided to check the connections to the megajolt and calibrate the TPS using the software.

 

After swapping the wires on the TPS around multiple times i finally got it right.

 

BUT there seems to be a problem that maybe someone on here can help me with...

 

The MPI TPS seems to have about 5 positions with the voltage (working from memory here) ranging from around 1.7v to 2v across those 5 positions. Ideally ide like to get a TPS with 10 or more (As the megajolt table is a 10x10)

 

Ive heard of people using Mondeo TPS's so maybe thats the way forward

[jackmason]

Ignore the above message about the 5 positions thing.

 

Ive checked the TPS with my meter and it gives a nice increase in voltage as i turn it. But the megajolt isnt reading all the variances. (See image)

 

This may be down to the length or gauge of wire i used, or the fact the wires are not shielded... 

 

Also, after running the TPS Calibration, it changes these settings to these values (Which are totally wrong)

 

I was competing in the TRS Targa Rally on Sunday with my car on these settings and im surprised it run at all!

 

Anyway, ive emailed Autosportslab to see what they can suggest. 

[Mini 360]

Good effort but what a lot of work and headache for the sake of £60, for a part developed and specifically designed for the job

[jackmason]

Good effort but what a lot of work and headache for the sake of £60, for a part developed and specifically designed for the job

 

Thanks, yeh i know what you mean, but the main issue was the fact the Weber TPS kit mounted using a threaded hole i use for my idle adjustment.

 

Plus i had a friend turn the adapter down, and another friend help make the bracket. I like doing customer little things like this.