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Megajolt on a fuel injected engine


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Welcome!

When you say "fuel injected" do you mean Lucas PI - or something else?  Assuming you even mean Triumph?

If PI, it's not really any different from putting it on a carb'd engine with the possible exception that you may not get a great vacuum signal for the load sensing.  In that case you'd need to add a throttle position sensor which isn't all that straight-forward on the PI throttle bodies/linkage.

Give us some more clues.... what car etc.... 

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Megajolt to a Boscl L-Jetronic Fuel Injection on a 1981 Fiat Spider.

My issue is where/how to pickup a signal going to the cars ECU that will trigger the injectors to open. 

The original distributor/coil ignition system is relpaced with the Megajolt/wasted spark ingition system. 

The signal wire originally came off the coil which has been removed/replaced with the Megajolt system.

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Prior to instatting Megajolt into fuel injected Fiat I ran the system on a test stand engine that was carb'ed with Weber IDF 40's, all ran well.

Noe the Megajolt setup is on a fuel injected engine, same type. Only issue is where do i get a voltage signal that will fire the injectors, remember prior to installing Mrgajolt the signal was coming from the coil that was part of the original distributor/coil ignition system but removed and replaced with the Megajolt/wasted spark ignition system.  

I have contacted Megajolt, because they are unfarmiliar with the Bosch Fuel Injection yhey did not have a solution. They did suggest acquiring the signal off the Ford EDIS module by attaching a wire to IDM pin location of the EDIS. I'm looking for other suggestions. 

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Rydere,

Are you confusing Megajolt, an ignition system that uses the Ford EDIS system to provide, er, ignition, with MegaSquirt, an allied fuel injection system?

MegaSquirt also uses a trigger wheel to time the injections.

John

 

 

Edited by JohnD
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2 hours ago, Rydere12 said:

Prior to instatting Megajolt into fuel injected Fiat I ran the system on a test stand engine that was carb'ed with Weber IDF 40's, all ran well.

Noe the Megajolt setup is on a fuel injected engine, same type. Only issue is where do i get a voltage signal that will fire the injectors, remember prior to installing Mrgajolt the signal was coming from the coil that was part of the original distributor/coil ignition system but removed and replaced with the Megajolt/wasted spark ignition system.  

I have contacted Megajolt, because they are unfarmiliar with the Bosch Fuel Injection yhey did not have a solution. They did suggest acquiring the signal off the Ford EDIS module by attaching a wire to IDM pin location of the EDIS. I'm looking for other suggestions. 

I think, as others have said, you need a trigger wheel/sensor. I don't understand how the edis module can provide the signal. (I did a couple of megajolt installs 12 years ago)

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Rydere,

Reading back in the post, you said, "Prior to instatting Megajolt into fuel injected Fiat I ran the system on a test stand engine that was carb'ed with Weber IDF 40's, all ran well"

I'm confused!  Do you mean that the engine HAD been injected, but you tested it with carbs?    

As said, MegaSquirt needs a crank position sensor, usually provided by a toothed wheel that lacks one tooth.   Then absolute timing is done in software.

John

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18 hours ago, Rydere12 said:

Only issue is where do i get a voltage signal that will fire the injectors, remember prior to installing Mrgajolt the signal was coming from the coil that was part of the original distributor/coil ignition system but removed and replaced with the Megajolt/wasted spark ignition system.  

Just re-read this. So your injection ecu had a signal from the original distributor/coil, but you want mejaolt to supply the signal now? Is that right?

it will depend on when the distributor setup sent the signal I guess....

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Yeah, I think we are reading it backwards. He has the Megasquirt working (so presumably has a trigger wheel, EDIS module etc) but needs a way to give the original L-Jet a trigger signal.

Presumably it previously got it from the distributor?

My thoughts are:
- EDIS4 has a 12v tacho out signal (pin 4 iirc, but check!), that might work

-All EDIS units also have a “diagnostic” signal (pin 7?) though this also produces a regular pulse when powered up, even when the engine is not running.

-L-jet is…… rather old and hard to tweak….. I’d be real tempted to bin it and use Megasquirt which will also do the ignition with the existing EDIS hardware.

Edit:

Some, if not all, versions of the Megajolt ECU also have a tacho output. (Don’t know which pin)

Google suggests that L-jet gets its rpm signal from the coil terminal so it’s possible that it wants a chunkier signal that 12v square wave. If so, you might find this useful

https://www.msextra.com/forums/viewtopic.php?t=69602

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