Thread: Throttle Position Sensor RRC/Disco - Better, Cheaper alternative fitted with Photos

Hi Hobbes, well done for thinking outside the square. In your opinion, is it likely to adapt to a Defender TD5 ? Cheers, 130man.

Good one Hobbes will be watching with intrest as will many others I am sure.
Dave

As promised here's the photos of the install - this works for any Hotwire Rangy or Disco or Def90V8

This is the finished job:
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The kit consists of a nicely machined adaptor plate which has a roller bearing pressed into the centre; a central shaft in two pieces which allows you to adjust the range of the TPS, a couple of Stainless allen screws and a allen key for the grub screw in the shaft.

The adaptor plate simply bolts on the manifold using the old screws.
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The through shaft consists of a brass shaft which is a push fit into a cast adaptor. This locks onto the brass shaft with a M4 grub screw. This allows you to "pre-load" the TPS. You'll find that with the brass tang horizontal the cast piece will need to be at about the one 'o'clock position for starters.
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The shaft simply locates in the adaptor plate
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This is the input side of the TPS. The shaft engages on the two raised triangles.
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Wiring You need to buy a Delco 3 pin connector. I used the $10 plug only option and cut the leads off the old TPS and fitted the Delco pins and plug, but I'd recommend spending $12 on the flying lead and soldering/heatshrinking the fly leads onto the old connector leads - it's less fiddly and gives you a convenient test point before you heat shrink the joints.

There's three wires: On my 90 RRC the colour code between the old plug and the old TPS is yellow (+5 V from ECU) Green (ground) Red (output to ECU)

SetupConnect a multimeter across red and ground. Locate the new TPS in the housing - easier to do than describe(!) but as you turn the TPS you'll feel it engage on the shaft drive and began to pre-load against the spring in the TPS. Turn on the ignition..as you rotate the TPS you'll see the voltage rise. You're looking for 0.4>0.5 volts when the locating holes align.

To adjust the pre-load you just pull the shaft out and adjust the angle and lock it off with the grub screw. It took me three goes to get this the first time and about 6 after I'd dismantled to take photos! Once it's done though that's it - just put the set screws in and check.

I found that with 0.458V at closed throttle I got 4.45V at WOT, which is well within the conditions required for the 14CUX to self calibrate.

In summary, the adaptor cost $100, plug $10, TPS $50 plus $9 postage and GST. It took an hour to fit but was fun 'cos it's not an oily job!
The only issue I had to fix was that the grub screw (M4 x 4mm) was slightly too long and fouled the adaptor plate. I couldn't find a M4 x 3mm but a bit of quick fettling with a file soon fixed it.

Steve at EFI Hardware is a top bloke and well up for a chat. I ordered on line at 3pm on Tuesday and had the bits in Sydney by 11am Wednesday. I stuffed up though and ordered an anticlockwise TPS rather than the CW type so he chucked a replacement in the post before he got mine back.

The actually TPS is a AC Delco TH40 part # 17106681 - common to Holden Barina, Commodores etc. At around $50 it's a sixth of the price of the Land Rover part and available anywhere..ok so the adaptor cost a bit more but I kinda think I've won this round!

beer o'clock then...
cheers
chris

Originally Posted by 130man

Hi Hobbes, well done for thinking outside the square. In your opinion, is it likely to adapt to a Defender TD5 ? Cheers, 130man.

Thanks for the support! As far as i'm aware though the TD5 has the tps located on the throttle pedal assembly in the footwell...same electrics/setup it's the mechanical interface that's the issue. But it was the same with this issue...fun to come up with an alternate - I'll dig around for you

Thanks for posting this fix Hobbes, just got my new TPS kit from EFIHardware, arrived in one day. The kit looks well made

Hi Nic - let us know how you go.
With 600 km done since the conversion have to report all very good..(granted the original Lucas part had done 150,000 kms and was obviously well stuffed) but the difference in drivability and smoothness through the rev range is really markedly better, and the hesitation off idle has gone.

Chris

p.s only problem with the kit as I mentioned earlier was the M4 x 4mm grub screw which needs fettling by file or Dremel to about 3mm - they're rare but most R/C model car shops have them for a couple of cents.

Just spoke to Steve at EFI hardware and although they dont have any kits on the shelf he is going to see if they still have the drawing to start making them again.
Otherwise the parts are simple and i reckon i could knock one up easily.

Hope that's what it is. I just want it fixed....


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