More speedo questions

Technical questions and answers about the Mazda Bongo

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Alvi
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More speedo questions

Post by Alvi » Sat Feb 09, 2013 4:15 pm

Hi. I'm new to this forum & bongo ownership. I've done a few searches on my problem, but there's still a few points I'm not clear on. I have a 2.0 petrol auto Freda, and the other day the mileometer stopped working. Speedo still works. The mileage is ....799, so it could be a mechanical problem, but I'm fairly sure my speedo is chipped, so it could also be the chip. I got another instrument panel from ebay, but there are no auto lights - hold etc, so I think it's off a manual & I can't replace the whole thing. I've taken the speedo out the spare, and by rotating a cog on the left of the mileometer, the mileage goes up & down. I'm hoping I can do this on the stuck speedo, get past the...99 & it will start working again! If not, I could fit the spare speedo, but I will then need to remove the chip. I believe this works by intercepting signals, so is the pcb or wiring altered when the chip is fitted? What would I have to do to remove it? There was no chip on the spare instrument cluster, so I think it just has a mph bezel fitted - but is there any way I can be sure of this? Lastly, how do I clock the spare speedo to match my mileage? I've tried pushing the individual numbers round, but they don't feel as if they want to move! Sorry for the long winded questions, but it's my only vehicle & I don't want to damage anything! :cry:

Many thanks, Alvi
321Away
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Re: More speedo questions

Post by 321Away » Sat Feb 09, 2013 4:40 pm

wiring is usually modded when chip is fitted, simple removal and all you need is a philips screwdriver (P2),the stuck at 99 miles is a sign its been played with at some point and not reassembeld correctly, usually just needs pulling apart and reassembling again and will usually work.

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Colin H F
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Re: More speedo questions

Post by Colin H F » Sat Feb 09, 2013 4:47 pm

smells like its been "CLOCKED" when you say stuck at 799 is that the total being displayed, or is there a few thousand in front of 799 did you take a note of the milage when you first got it
prior owner of >>>>1999 2.5 diesel ex tin top &FORD FREDA 2000 2.0 LTR PETROL
Alvi
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Re: More speedo questions

Post by Alvi » Sat Feb 09, 2013 7:44 pm

I bought it from a jap import specialist & part of the sale was conversion to mph. Whoever did this also converted the mileometer from it's km value to the miles equivalent, which is around 57k. They do a lot of these conversions, so should know what they're doing. It's the fact that it was about to click over 3 digits at once when it stopped that maked me think it's mechanical. I've done about 600 miles in it, so it's clicked over x99 several times without a problem before. If it's been damaged when converted, I'd be better fitting the spare speedo, but I'd like to be sure about how to take out the chip. Surely of the wiring is modded to fit it, it must be changed back to remove it?
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westonwarrior
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Re: More speedo questions

Post by westonwarrior » Sat Feb 09, 2013 9:07 pm

if you take the cluster out you will see the chip attached to the back by 3 wires and i wire from the loom which has been cut

just remove the wires replace the screws, reconnect the cut wire and all will be well
Alvi
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Re: More speedo questions

Post by Alvi » Sat Feb 09, 2013 9:32 pm

Great! Thanks for that
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Simon Jones
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Re: More speedo questions

Post by Simon Jones » Sat Feb 09, 2013 9:39 pm

This is a typical speedo chip installation. The yellow wire goes to the blue/white wire which is cut just before it gets to the connector at the back of the instrument cluster.

Image
Alvi
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Re: More speedo questions

Post by Alvi » Sun Feb 10, 2013 1:00 pm

Thanks, Simon, I think I've got it now! I assume the red & green to the chip are +ve & gnd. Looks like the track the blue wire is connected to goes up to the connector on left on picture. So a wire to this connector is cut, the yellow wire picks it up, and the blue wire feeds it back to the pcb :? I guess when I pull it apart it will be clear [-o< Before I do this, I'd like to rotate the numbers on the km mileometer to match the mph on the broken one - 57,800 miles, so about 93,020km. Any tips on this, or would I be better just leaving it - it's currently about 183,000km.

Thanks for your help with this, Alvi