The Peugeot Jetforce 125 or How a scooter becomes an engineering project

Synerject Contact formThis is now getting to be a saga. I work in the “Parliamentary Triangle” in Canberra – you know the capital city of Australia not Sydney or Melbourne as some would believe – and in 2014 the ACT government in concert with the “National Capital Authority” (aka the NCA) decided to introduce paid parking. I have no real issues for charging for the land use and maintenance of the car parks but $12 a day in an area where there are no national tourist attractions and no shops is a bit rich.  $5 a day I would not have any truck with so I decided to fight back and but a motor scooter.  As the NCA uses a system on “pay and display” and as there is no way of securing a ticket on a motor cycle, they have exempted motor cycles, scooters included from the impost.

So there are several scooter dealers in Canberra and I happened to be close to the one in Mitchell (name withheld) where I was temporarily working, I went over and spied a very pretty red Peugeot JetForce 125 EFI. As I’d had a great experience with a Peugeot 407 in the past and we had a little family history with Pugs, I plonked down $2500 to become the owner. First mistake – zero research – the dealer for these went broke in the GFC in 2009 and there is no Pug scooter representation in Australia.  Second mistake – any simple research would indicate that these scooters have all sorts of reliability issues. Still I took it for a test ride and it seemed to go OK at the time.

Well, the issues started from Day 1. I rode it to work next day from North Lyneham and by the time I got to Commonweath Ave, the bike wouldn’t do over 60Km/h. I rang the dealer and organised to take it back that afternoon. By the time I got out to Mitchell the bike wouldn’t do 40Km/h and was positively lethal in terms of throttle response. The dealer put the bike on his “do when other stuff was done list” which was pretty surprising seeing how I had only bought it the day before so it took almost a week until I got it back. By then, it has magically fixed itself. The mechanic stated that he had cleaned the injector, replaced the fuel and the spark plug. He actually just got lucky.

The bike went OK for about another 3 months – well after any sort of warranty period would expire then the same trouble started all over again. The scoot would just go slower and slower until eventually it would just idle parked up in the gutter. I did find it would “go” for a small distance, maybe 500m by turning it off and restarting. Each time I did this, it would go again but a lesser distance. It quickly gets to the point where it will only start and idle.

Now the saga begins. Google is invaluable here. The scoot runs an EFI system originally designed by the Orbital Engine Company of Perth in Western Australia (a great co-incidence). The original Orbital Engine was effectively a dud as they could never seal or cool it effectively but they did develop and patent a 2-stroke compressed air injection system which required the development of a cheap to manufacture ECU (Electronic Control Unit). This ECU was also found suitable, with minor adjustments, for small 4 stroke engines.

Through various purchases and divestments of capital, the SynerJect company bought a percentage of Orbital and took over the IP and marketing of the small fuel injection market.  How did I find this out? I rang Orbital and one of their engineers actually talked to me! I’m still grateful that they would bother to do this. Synerject, on the other hand has a somewhat hostile message on their site which states that unless you are an engine OEM we won’t talk to you.  The two stroke version is called “DITech” – Direct Injection Technology I assume and is reasonable common on 50cc 2-stroke scooters from Peugeot, Aprillia and I think Suzuki has one as well. Peugeot then used the Synerject 4-Stroke system on a number of models mine included. The components seem to sourced from all over the world including Mitsuba for base electrics, Phillips actually make the ECU, Bing for the throttle body etc.

I emailed Peugeot in France and they don’t have any capacity to talk to some random owner in Australia where the dealer doesn’t exist. Spare parts / diagnostic support – forget it – so I’m now in the grey area of people who “might” have some parts or “might” know something about this puppy.

First thing I did was replace the plug and change the fuel. No idea how a machine that recovers temporarily would recover from fuel problem but it was a start.  During this period my research showed that the diagnostic computer was actually a Nintendo Colour Gameboy with a specific cartridge. I’d been to “Motorini” Scooters in Phillip where the owner Nico and his mechanic gave me the final judgement on Peugeot Scooters – just say no.  Their words were “If you had of asked we would have said just don’t buy it” – that said Nico lent me his Aprilia diagnostic cartridge and $5 gameboy. I took it home but the diagnostic connector is different and I wasn’t about to “hack” his cartridge. The cartridge is almost certainly a DITech (2-Stroke) not the 4-Stroke

Couldn’t get it going so I loaded it on the trailer and took it 300Km to my real home in Sydney. Got it into the shed and noticed the battery was a bit weak so I charged it overnight and for some reason, it decided to run properly. I fanged it up and down the road outside and it ran as good as new. I ordered and fitted an ebay $12 voltmeter to the scoot just so I could keep an eye on the charging system.

Loaded it back on the trailer, 300Km back to Canberra and it lasted 3.5 days. Exactly the same symptoms but I thought the battery recharge was significant (it wasn’t) and bought in turn and new battery ($80) and regulator ($65 from E-Bay).   The voltmeter actually told me so but I was getting desperate.

Trailered back to Sydney – the trailer is doing a lot of Km and its now back in the shed. I’m determined no to just “junk it” so here is where I’m at…

– When I disconnect the lead from the TPS (Throttle Position Sensor), nothing changes. i.e. the bike acts like there is no TPS. It will start and marginally throttle up to 5000 RPM then dies back to idle. I suspect that the minor throttle up is due to the opening up of the throat leaning the idle mixture up enough to increase the RPM.  I’ve removed the TPS from the bike to see if it was the issue. The ohms across the device 2K (2040 actually) and the wiper moved linearly from 2K down to 1.1K – there is no bumps and wiggles in the response to it seems OK – problem is – I don’t know what the correct values are and there seems to be zero information. I’ve emailed the “Bing” company in Germany (they make the TPS) and asked – currently awaiting a reply. I actually think the problem is in the ECU as there isn’t anyway I can think a simple variable resistor would have issues around power being re-applied unless it was overheating (Voltage Regulation issues?)

Further update. I measured the voltages on the TPS. With the plug disconnected I get +5V across the resistor (4.99 actually) so the 5V regulator in the ECU is OK. When I connect and back-probe the wiper to earth I get a smooth +0.7V to ~4.4V. Would look like sane numbers. Zero Volts on the wiper would be a fault condition (Open Circuit) if I was an ECU. 5V would be almost short. The fickle finger of blame is now firmly on the ECU input circuitry.

The nice people from Bing have responded and I now have the full technical data of a Type 72 Throttle Body and TPS. The specifications match exactly what I measure on my TPS so now its 100% the ECU. I can provide the TPS specs if anyone is interested.

Decided to attack the ECU last weekend. Takes 1 minute to get it out of the bike but it is encapsulated with silicone rubber. Had a go at cutting some of it out but it is almost impossible to remove down at the board level. 90% of the board components are surface mount so any attempt to remove the rubber mechanically will certainly damage something. Without a circuit diagram, if I chipped off a resistor etc, I would be totally stuffed. I did find out that the interface connector is a 22 pin version of the ATX PC (20 pin) connector. Molex 5566 series so I can order a male 5566-22A from Element14 (or someone) and not totally stuff the bikes harness.

Have ordered the V0.3 board so looking forward to populating that and getting stuck into building a “New” ECU. It should be a lot of fun.

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