Jazz GD CVT Economy

[JackH]

Sorry JackH i was looking by your name "My Honda: GE 1.4 EX" so I thought a GE. Apologies

Yes, that's where all this GD/GE business gets confusing - late mark 1 cars like mine are GE too.

Is there anything like VAGCOM (VW OBD diagnostics lead / application) available for Hondas? Something along those lines would usually give you access to data like engine temp etc.

Yes there is, Honda dealers have their own system HDS, and you can buy a Chinese clone - it's a lot dearer than the VAG-COM interfaces though, about £90 last time I looked. These diagnostic tools can be very useful indeed, but I'm holding off buying the Honda one until I need it.

If you want to read engine fault codes, temperatures and other live engine sensor data only, one of the generic ELM327 type OBD2 USB cables or bluetooth adapters will do that, and they are only a few pounds.

There will be an inlet temperature sender for the ECU. Not 100% certain on the Jazz, but they are usually completely separate from the dash outside temperature display.

It sounds like you have checked all the obvious, and as neddy says, I would be very surprised if there's a lambda problem if there's no EML on and exhaust emissions turn out to be good. They don't normally fail unless contaminated by something, for example an engine burning oil or head gasket failure, etc.. Unless something shows up on the emissions, I would leave them alone for now.

It's definitely worth a look at the EGR valve. They can fail without significant symptoms, and on a car which has done little mileage,  it's possible that it has been tootling around town all its life. It's worth a quick check and a clean out with some carb cleaner - nothing oily.

Also check for sticky calipers, as you suggest - it's the first thing I go to if there are any mpg worries. Feel the centre of the wheels after after a good run, see if anything unusual is going on. Fronts may become lukewarm or 'aired', with the two sides even, and the rears should always feel cold.

I think the tag under the bonnet says ‘GE3’ but will check tomorrow.

As per my other reply, EGR cleaned.

I’ve had generic code readers before and not knowingly been able to read temperatures etc. Any recommendations on one to use with this and do you know what temperature these usually sit at?

I only ask as per my previous comments, the economy on the VAG TDIs I’ve had could be knocked quite a bit just through running a bit cooler than they should be.

Thanks

[Jocko]

Easiest way to know the car "type" is from the VIN number (bottom of windscreen and V5 document). Mine shows thae GD designator. JHMGD57106S21****
Yesterday I did 91 miles of mixed routes, ScanGauge E showed max temp of 83°C and 55.6 mpg for the day.

[sparky Paul]

I’ve had generic code readers before and not knowingly been able to read temperatures etc. Any recommendations on one to use with this

I use one of the ELM327 USB cables and an old version ScanTool software on the laptop and it is able to read live sensor data, including temperatures. As I say though, it will only access engine related stuff, unlike VAG-COM on the VWs.

Something like this - https://www.ebay.co.uk/itm/UK-ELM327-USB-Interface-OBDII-OBD2-Bluetooth-Auto-Car-Diagnostic-Scanner/183027395053

If you can wait for postage, they are a couple of pounds cheaper from the far east.

I also keep one of the cheap bluetooth ELM327 devices in the car, also very useful with 'Torque-Lite' app, or something similar, on an android phone. Those Scangauge devices use a similar OBD2 interface with a purpose built user interface, with a bit of ingenuity you can get the same functionality with a £3 bluetooth OBD2 interface and an android phone.

For access to all car systems, you have to use the Honda HDS, or a clone.