On this page I hope to outline a project I have started to get the Locost Toyota 4age engine running on a Megasquirt DIY Engine Management system along with adding individual throttle bodies from a bike engine.
The throttle bodies should require a small amount of modification to fit but are a worthwhile addition to the engine.
See the links page for the Megasquirt pages.
The Suzuki GSX-R Throttle bodies stripped of some of the items not required. These are to be fitted to engine along with a Megasquirt DIY Engine Control Unit.
The home made inlet manifold plate in construction, holes to be smoothed out yet. If you look carefully you can see the scribed outline of the inlet gasket ready for sawing around. There are 4 inlet tubes to be welded on to accept the throttle bodies. The TBs will be mounted with a short section of silicon tube and clamps.
The completed Megasquirt (MS) kit built up and being tested using the 'Stimulator'. It is running and connected to computer.
Off screen photo of the tuning software 'realtime' readout from the Megasquirt unit with Stimulator connected. The 'stimulator' mimics a cars outputs to test the MS unit. The row of green dots followed by red circles are the Oxygen sensor output, the red circles turn to red dots as oxygen output in exhaust increases.
This is a sample of what MSnS Extra really looks like on screen, not my blurry picture !
The manifold made up. The aluminium tubes were expertly welded by MK Engineering (see links).
The manifold with throttle bodies lined up, trial fit after adding spacers. The rubber joints and bellmouths were in the original airbox. I will try and get another couple of bellmouths. To use the original very long allen headed joining bolts, I cut off the threads and welded on a cut off bolt section to match additional length.
Project has stalled somewhat at the moment. I spent two days trying to interface the MS to the standard Toyota ignition system with mixed success. I'm currently awaiting the arrival from Farnells of an interface chip for the reluctor senders in Toyota distributer. I nearly had it running as standard but the signals were just not strong enough.
I've made progress then a backward step. The chip arrived from Farnell and I made up a PCB to take it. Connected it to the MS and it eventually worked, converting the signal from the Toyota dizzy into a signal that MS can read.
Had a problem over the weekend whereby the MS suddenly gave erratic and weak signals. Cut a very long weekend story short, it would appear the 12v track on the MS PCB burnt out. I've made a repair and a mod to the spark output transistor and the unit is now trying to fire the car up !!
I've probably gone back to where I was as above. I now need to check all the signals and their timing relationship to ensure the spark and fuel all are at the right points. Seem to be close to getting it running now.
Well, after a years layoff and many changes in personal circumstances I've taken up the challenge again. The Throttle Bodies will have to wait but the Megasquirt has recommenced. I have had an operation on a damaged ankle which has left it weak. I need to change the brakes and use a servo system, this means I need a vacuum takeoff from inlet. Something which is difficult on TBs.
In the last year many changes have been made to the MS software, amongst them was a new dual wheel decoder routine. This is just the programme I needed for the 4Age as it has two VR senders in the distributer, one of which has two outputs, G1,G2. By combining these outputs into one and using the other NE seperately, I should be able to get it to work. This is a very condensed description, it has taken a month of fiddling to get to the stages below.
Using a ready made multi function board by " error* " (yes that's his user name) from the MS forum, I made up a set of dual VR conditioners which take the signal in from distributer and convert it to a square wave signal that the MS needs. Putting these signals into MS immediately showed a problem, crosstalk. Now, the recommended resister values on the input just did not seem to stack up so I did some experimenting with an oscilloscope and changing the values. Finally I was able to get clean signals into the MS which responded with an output that turned out to be inverted ! Quick alteration to software parameters then the car actually started and ran !!!
I spent an evening tuning the fuel parameters, it was extremely rich. I did ruin one set of spark plugs and fouled a second set. Eventually the car would start and run but with a slight misfire at tickover. I put this down to needing another set of plugs.
Now the sad part. Next day I went to try the car again and it wouldn't start ! That's the current position and I'm trying to source the problem. It has tried once to fire but immediately died and wouldn't respond. Trouble is when you are trying new settings you only get about 10 minutes cranking before the battery is flat.
Megasquirt with error* daughterboard fitted. Notice the twin input converters on the right.
Photo during installation and wiring. I used 4 pieces of blue silicon hose as joiners with large Jubilee clips.
Note that the throttle bodies are upside down compared to bike installation, this was to get the throttle cable the right way up and at the right end of engine.
Well, an update, now end of May 2007. Different engine fitted,New Megasquirt V3 fitted, complete engine/ecu rewire to suit the Megasquirt. 36-1 missing tooth wheel fitted to crank pulley along with VR sensor. New exhaust sytem fitted and wideband lambda sensor system fitted. Had to have new silencer after I ruined the first one whilst repacking it.
Car starts first time and runs nicely, only problem I have had, is getting the fan to run correctly. Finally cured by fitting a fan switch in coolant outlet.
April 2008. Ignition is now run by Megasquirt with distributer removed and blanked off. The 36-1 wheel is used in wasted spark mode driving an Escort coilpack and modified Toyota leads. Works fine after some initial troubles.
