Mayfair86
Member Since: 25 Nov 2020
Location: Bedfordshire
Posts: 11
  
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| D3 V8 project limiting throttle |
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Evening All,
I have my Manual AJV8 Disco 3 project that is now running and on the road. It is an awesome bit of kit however I have an issue with the performance. The ECU is limiting the throttle to between 16% and about 25% (increases with revs). As you can imagine this restricts performance quite drastically. No codes are present other than 'missing transmission control module bus signal/message' due to the obvious lack of auto box module. At first I thought it was going to be the P/N switch being permanently 'on', however this is now on a switch on the dash for testing and makes no difference. I have swapped the throttle pedal in case that was limiting it as I know the auto and manual pedals are different. With the engine off but ign on I can get 99.9% TPS by pressing the pedal, I get between 56% - 100% pedal sens B but this reaches 100% at a TPS of 52.2%, 13.3% - 77.3% on pedal sens D and 14.5% - 75.7% on pedal sens E. This does seem a bit strange to me but it's basically the same for both pedals, and the TPS still goes to 100%?
I have earthed the 'Sport/Manual' wire on the autobox loom incase that was causing problems but no difference.
I need to get all the modules re-coded to remove the autobox features and I will be getting the ECU re-mapped so I can solve most issues with that but I would quite like to try and get full throttle with what I have at the moment.
I'm sure it's going to be a wire on the auto loom that either needs a signal or to be grounded to tell the ECU that it's in D but I can't find anything obvious on the wiring diagrams!
As always, any help is greatly appreciated.
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 7th Jan 2023 10:27 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10387
 
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I think the ecu and gearbox talk a lot more than you think.
Retard ignition before gear change I think. Etc
Could be a safety thing, not Reving too much if comms lost
I’d get the Ccf or config sorted
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| 7th Jan 2023 11:06 pm |
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Flatlander
Member Since: 20 Jul 2015
Location: Here
Posts: 575
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It's not as old tech as you think - there will be expected / missing messages from the auto 'box - mainly requested torque etc. on CAN, these cannot be bypassed by physical means. TBH, I'm not even sure the ECM is capable working with a manual gearbox, the whole thing will have been coded for signals from an auto 'box.
As above, get it coded for the config you have and go from there.
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| 7th Jan 2023 11:22 pm |
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