Just starting out

General Megajolt Questions and Answers

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KITT
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Joined: Thu Aug 26, 2004 6:53 pm

Just starting out

Post by KITT »

Hope this is the best place to post this!

I'm based in the UK and will be implementing an MJLJ on my 2lt Ford Pinto engine running twin 45 Weber carbs. I've already got a coil pack and EDIS module from a 1994 Escort for £10 so am well on my way to keeping it within my budget (i.e. as cheap as possible!).

Just wanted to know what the current lead time is on ordering from the US and also about the mod needed to use a trottle pot. sensor instead of a MAP sensor?

I'll be keeping a website log with photos to help anyone else implement this great system on UK based cars as there's not that much info out there at the moment.

edowner
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Joined: Thu Aug 26, 2004 6:53 pm

TPS sensor

Post by edowner »

Hi,

I've been looking into fitting a TPS myself - there is a forum topic called 'TPS Sensor' which should answer your question. Essentially the TPS can be used as a direct replacement for the pressure sensor as both have 3 connections that are used: +5v, ground and an output voltage between 0v & 5v (which is converted to kPA (pressure)) which increases linearly with pressure. A TPS is a variable resistor which outputs a voltage between 0v and 5v increasing linearly with throttle position!

The only drawback is that the software will still show pressure instead of throttle position, but this is arbitrary really - it might just as well say sensor output voltage!

FYI, a TPS off any car should work (if you're on a budget and can make it connect to the throttle spindle or linkage on your weber carb), just make sure you measure the resistance between the two outer pins on the tps and it doesn't change when moving the tps spindle, whereas the resistance between one of the outer pins and the centre pin should change when you move the tps! I've got one off a ford mondeo for £5 (ebay) which should fit the bill!

Hope this helps - good luck with everything!

edowner
Posts: 0
Joined: Thu Aug 26, 2004 6:53 pm

TPS instead of MAP

Post by edowner »

By the way, I must thank Josh B for answering a few questions concerning why TPS can be preferable to MAP in certain circumstances.

Essentially when you have one carb barrel feeding one cylinder and you try and take MAP from that single barrel it will fluctuate substantially more as the valves open and close, whereas when you have a manifold and carb setup which feeds all four cylinders simultaneously this fluctuation is not as pronounced,

Speaking to Guy Croft (www.guy-croft.com), fiat twin cam tuning expert, the individual manifold feeds could be connected together to remove this effect and hence use manifold absolute pressure.

Best regards, Ed.

KITT
Posts: 0
Joined: Thu Aug 26, 2004 6:53 pm

Thanks

Post by KITT »

All seems very logical :o) I've (hopefully) got a proper Weber TPS coming my way as a friend has one that he no longer needs as he's upgraded to trottle bodies, so that should work ok.

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