Megajolt installation Firenza 2000SL

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Re: Megajolt installation Firenza 2000SL

Postby fistfullofV5's » Sat Oct 31, 2015 2:25 am

Hi all. So today I hooked up the battery to check if the circuits and looms I've made were working as intended. As a precaution I pulled the fuses to the Edis and Megajolt as at this stage I only wanted to test the operation of the relay circuit. This checked out ok so I replaced the Edis fuse,pulled no1 plug lead and connected it to a spare sparkplug clamped to an engine bracket. I cranked the engine to test for a spark and was rewarded by a healthy blue spark. At this point I didn't need to have the Megajolt powered up,at least not until the engine has run without it. The Edis system is capable of running the engine at a constant 10 deg advance as a limp home feature,so it makes sense to make sure all is well before adding in the complication of the Megajolt. I'll get the engine running on Edis alone and then replace the 3amp Megajolt fuse and load up a map. On the subject of spark,you'll only usually get one if the vr sensor is connected with the correct polarity. On the internet a search for vr sensor polarity will throw up contradictory information as not all vr sensors have the same polarity. In my own case the information I found for the sensor I was using didn't match what I was finding on testing I.E they were telling me I had it connected the wrong way round. As an experiment I popped the terminals out of the housing and reversed them. There was no spark. The moral of all this is if you don't get a spark,swap the vr sensor wires around and try it again.
I was now at the stage where I was ready to fire up the engine (Edis only) so with everything in place I turned the key. The engine coughed and spluttered a little as it started to pull the fuel through and was right on the point of firing properly when there was a very strong smell of petrol. As I looked to see what was wrong I was met with the sight of the front carb wetting it's pants all over the floor. An O ring on the jet adjuster had failed and fuel was pouring out of the float bowl. That ended the days entertainment,and it became painfully obvious that my carbs are not in tip top shape. A service kit from Burlen Fuel Systems is on the way to sort this out. It was a case of one step forward and one step back which is very frustrating. I bored my girlfriend with my tale of woe and got told "what do you expect if you're going to play with old cars" Indeed.
Regards,Dave :imsmiling:
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Re: Megajolt installation Firenza 2000SL

Postby 1972nail » Sat Oct 31, 2015 10:55 am

My carbs did eaxctly the same thing. I tried using a standard O ring from a box full I have in the garage, no use. The correct O ring seems to be a particular section to seal properly. I found the cheapest place to get them was a Jaguar specialist in Arizona! £2.50 inc carriage.

That got it leak proof until I got a pair of rebuild kits for £5 on ebay. My Scottish heritage is shining through :D
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Re: Megajolt installation Firenza 2000SL

Postby fistfullofV5's » Sat Oct 31, 2015 12:24 pm

I should have you do my shopping for me at those prices! I've bitten the bullet and gone for genuine rebuild kits for both carbs,not cheap but then neither is a fire.
Regards, Dave.
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Re: Megajolt installation Firenza 2000SL

Postby 1972nail » Sat Oct 31, 2015 9:45 pm

The kits I got on ebay were 'service kits' instead of rebuild kits. They were for a Range Rover I think. Had to wait a while for them to come up for sale but the car wasn't on the road so I had time to hang on and get a bargain :D
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Re: Megajolt installation Firenza 2000SL

Postby fistfullofV5's » Sun Nov 08, 2015 2:41 am

Today with Stromberg service kits in hand,I headed up to the Firenza. After servicing the carbs and going through the process to re-centre the jets,I was ready to start the engine to test the Edis only function. The carbs filled up nicely with no leaks but the motor didn't fire. I checked the 12v feed to the coil,the 12v to edis and the relay circuit and all checked out fine. The only other thing to check was the vr sensor wiring,so I put the multimeter on it to check for continuity and lo and behold one of the wires came up as a dud. I think what had happened was when I swapped the connection around to see if the Edis would fire with the connections either way ( it wouldn't ! )one of the connections had broken unseen under the heat shrink. I did a quick temporary repair and re checked for a spark. Success!! Next turn of the key the engine started instantly and timed up bang on 10 deg which is the Edis default/limp home mode. The damaged connector will be replaced next time,and I'll power up the Megajolt and load a map I've made from the distributor advance figures in the factory manuals. How good a map it is remains to be seen but it's nothing some time connected to a laptop can't solve.
Regards,Dave.
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Re: Megajolt installation Firenza 2000SL

Postby fistfullofV5's » Tue Nov 17, 2015 2:44 am

Hello all, today saw me back working on the Firenza's new ignition system. First job was to fit new connector pins into the junior timer connector which fits on the vr sensor after last weeks little accident with the wiring. A quick continuity test and start up was done to check I'd got the wires the right way around. All my test starts have been performed without the cooling system fitted in order to vastly improve access to the sensor and trigger wheel should any remedial work be needed. As the engine was run for only around 30 secs this wasn't going to be a problem for the motor. Now I was ready to do longer runs,the radiator was refitted and the system filled. The Megajolt that I've used doesn't have a power indicator led and even if it did,it's position under the dash would hide any led from view. First on my list when troubleshooting is to question if there's any power to the thing not working. My solution was to fit a power indicator led into the blank switch cover in the dash.
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The arty dark shot shows it better
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As long as that little green light is lit,the Megajolt has power. I did this because if the Megajolt has a fault Edis will keep the engine running on it's own at a constant 10 degs advance,so the power led will help to speed up any fault diagnosis.
Next thing was to test the engine on the base safe map that Autosport Labs make available to get you started. I have found it's best to test with the safe map first to make sure that the system is working as expected before changing anything. Megajolt is a blast from the past with it's use of a serial connector for the data link,it's a curious choice and I don't have an explanation why it's used. As my own and most likely your laptops don't have serial connectors on them anymore, you'll need a serial to usb converter shown plugged into the Megajolt.
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This is a better picture of what you'll require
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As this is in a fairly awkward postion and I'm not as supple as I once was,the connector will remain in place with the cable tucked out of the way till needed.
With the laptop running the configuration software I had to check if the Megajolt was connecting. If you see the message could not open port,it's because windows has assigned a different port to the default port 1 that Megajolt is set to. Go into device manager and check which port the adapter is using then go into the configurator software,tools,configurator options and alter the com port setting to match what you've just noted in windows device manager.
Test run complete and without incident I loaded up a map. I'd spent some time translating the factory distributor timing figures into a map,but just to compare what I'd come up with I had a look through the online map library. I found a map for a Vauxhall 1.8 8 valve which looked very similar so I uploaded it to try. First impressions were that it worked really well and it would be a better starting point than the distributor based map.
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Pic shows the 1.8 8 valve map running with from left to right the advance the rpm and the vacuum as seen by the map sensor.
Incidentally,when you load up a map it first goes into the ecu's memory as a temporary setting. This means that you can test and alter settings freely but it should be remembered that if you then shut the engine off the settings will be lost and the last flashed map reloaded by the ecu when you restart. To prevent this, once you are happy with the map you need to click the button "commit configuration to flash" to write the map to the flash chip. Only then will the map stay in the Megajolt memory after a power off. When I next get the chance,I'll set up the rev limiter function.
Regards, Dave.
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Re: Megajolt installation Firenza 2000SL

Postby droopsnoot » Tue Nov 17, 2015 11:23 am

Thanks for the update. I must admit, you've made it sound very simple, and it's moving up my list of things to have a go at, especially given the issue with vacuum advance on the normal Dellorto manifold.
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Re: Megajolt installation Firenza 2000SL

Postby fistfullofV5's » Tue Nov 17, 2015 9:33 pm

Hi,as long as you work logically and methodically it isn't difficult in all honesty. It's a really worthwhile conversion especially working with side draft carbs which can really mess up a distributors world vac wise. I once set one up on a Mini running a 45 Weber and had to drill and tap the manifold to get a reliable vac source. I used mig tips drilled out to 1mm in that instance and joined the two with a y piece.
Regards, Dave.
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Re: Megajolt installation Firenza 2000SL

Postby fistfullofV5's » Sat Nov 21, 2015 2:08 am

Hello all again,a wet cold and windy day saw me back at the Firenza laptop in hand to set up the rev limiter on the Megajolt. This is a very straight forward thing to do and from start to finish took around 10 mins all in. First step is to click on the options button in the configuration view in the software.
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On the left are the user configurable outputs none of which I'll be using but an example of their use could be to trigger a variable valve timing cam (rpm based action) or a water injection sytem (load based action) and many others I can't think of. The additional configurable outputs on the right hold most interest in my case,and in particular the rev limiter. So I could test the process without stressing the engine,my ears or the neighbours,I set the test limit at 3100 rpm. You can see that the scale beyond 3100 rpm is shaded darker.
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With this limit entered I brought the revs up to trigger the limiter. How it works is pretty simple,at 100 rpm below the set limit Megajolt reduces the advance to 0 degs advance reducing engine power considerably and performing as a soft cut limiter. It's similar to when you top out the revs on a diesel and it runs out of puff in it's effect. If you had the need, I would think it entirely possible to add a hard cut limiter as well by combining this and one of the other user configurable outputs. In the pic below you can see that the advance is at zero as the limiter kicks in.
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After the test,I set the limit at 5500 rpm then clicked the button "write ignition configuration" to save the modification into the map
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then finally clicked the button "commit configuration to flash" to save it to the permanent memory.
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You can if you want alter the settings so that any mods you do to the map are automatically saved to the flash memory,but I prefer not to do this as I like to recheck all mods before saving permanently. It's entirely up to the user.
One small but vital thing I'd forgotten to mention earlier in the thread was the ignition leads. You need to either convert your existing leads to Ford gen 1 fittings,
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or use an off the shelf set. I found it easier and cost effective to use 2 sets of 1991 Ford Escort leads (Bosch B887) from Ebay and use the longer leads to make a set to fit.
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It's a fiddly job to fit those gen 1 lead fittings and for me life's too short so I went the other route.
Regards, Dave.
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Re: Megajolt installation Firenza 2000SL

Postby 1972nail » Fri Mar 23, 2018 8:30 pm

Hi Dave, Do you have an update for this thread? I'm interested to hear how you've got on.
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