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Discussion Starter #1
Many members on here have recommended that I reset my Adaptive Values since my p38 has stood for 18months and I've replaced the Headgaskets.

What does the Adaptive Values Cover?

I've found that my OBDII cable will reset short term and long term fuel trims and any faults. Is there much more that an adaptive values reset does? Or will this fuel trim reset do the job?

I'm just struggling to get to anywhere with testbook etc as I can't drive it until I sort it!
 

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JACK'S GRANDAD
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IIRC correctly there is a sticky in the diagnostics section covering drive cycles etc.
Basically and rudimentary, resetting the values makes the ECM relearn all the inputs from the TPS, IAC, and so on. If you were to swap a TPS for example, the rig would probably idle high until it learnt the "new" inputs from the TPS compared to the old one. ie if the old one was at say .5v at idle, and the new one was at .8v at idle, it would think that the accelerator is being depressed until it figured out that the new idle voltage is actually the .8v. Resetting the values makes it figure it out instantly as opposed to a month of driving.
Make sense?

Martin
 

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sotal said:
Many members on here have recommended that I reset my Adaptive Values since my p38 has stood for 18months and I've replaced the Headgaskets.

What does the Adaptive Values Cover?

I've found that my OBDII cable will reset short term and long term fuel trims and any faults. Is there much more that an adaptive values reset does? Or will this fuel trim reset do the job?

I'm just struggling to get to anywhere with testbook etc as I can't drive it until I sort it!
Gday,
Well both adaptive values shoulkd be around the same value,eg mine i reset yesterday and now are 229/229.
I think reading your previous post your car was on LPG???
Make sure all is good and serviced with it every 12months
Look at main idle settings make sure all is good ,then reset Adaptive values now should be of similar value , Drive car in petrol for 20min taking it easy so it can relearn itself ,then running on gas should be fine :thumb:
 

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Resetting the adaptive values is a good idea - but only after everything is properly set up and the engine is running properly.I doubt your OBD reader will do more than reset the long term adaptions,its unlikely that it will do the stored closed throttle position,which is not adaptive,just stays where it is set by Testbook or whatever diagnostic gear is used.
You cant reset the short term trims as these are constantly changing when the engine is running closed loop,the long term trims just adapt to keep the short term trims around the middle of their range.
So have you got both oxy sensors switching and the engine firing properly on 8 ?
 

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Discussion Starter #5
Ally - According to the OBDII software both sensors are working correctly, going between 0 and 1v. I have also switched them round to ensure they are working correctly. (The fault stayed in the same place proving they are both working)

I'm pretty sure it's runnning on all 8 but I was surprised at how well it runs/sounds when only on 7. We hooked up the obdII with an RPM readout today and then disconnected the live HT leads one by one to see how much the revs dropped. They all made it drop an even amount. The only thing we noticed doing this was that the revs aren't constant on idle every few seconds the revs dip for a second or two then pick up again. You can see the needle move a tiny amount and you can just feel it. The idle setting we were using was 928 rpm, and every few seconds this dropped to 896 rpm. Disconnecting a HT lead dropped the revs to 864rpm but then it occasionally rose to 896rpm. (I'm not sure on the resolution of the figures from the obdII software - seems a bit to similar so I presume that it steps from 928 to 896 then 864) we got the same 864rpm occasionally rising to 896rpm every time we pulled a lead.

Is it also normal to struggle to set the rpm to approx 800? I'm using the adjuster on the throttle cable in the engine bay behind the TPS. Is that the correct place to set the idle? From 928rpm if I turn it to reduce the revs it suddenly drops to about 650rpm, then you try to go back up and it jumps back to 928rpm.

It is Bank 1 which is running rich which is passenger side (UK vehicle)

The short term fuel trim on Bank 2 varies mostly between 5% (Lean -) and 5% (Plus +) occasionally going as far as 10% either way when revved etc. On Bank one though the majority of the time it stays high. Sometimes it has stayed at 25% (Rich +) other times (it seems to change between switching off and starting again) it has only been going to 10% (Rich +) but it always shows Rich except once when it decided to show 25% (Lean -) Not sure if that was just a hiccup!

The software which is showing this is EasyOBDII. I'm not 100% sure what 25% (Rich +) means but I thought it meant that the lamda sensor is reading that it's lean and trying to richen it? Is that right or is it the other way round?

Any suggestions as to what to do next?


Selby - what are those readings? and what are they from? My car is running on petrol - I seem to have run out of gas!
 

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JACK'S GRANDAD
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Idle should be set via the TPS and ecm. Adjusting the cable will make it so there is no slack in the throttle cable, which is a bad thing BTW.
Back off the throttle cable and leave a little slack. The adjust the TPS. I think you will find that the ecm is going to do its thing regardless though.

Martin
 

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Cheers
 

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Discussion Starter #8
Thanks for that - will adjust it but from a quick guess it will be at about 650rpm like that - is that OK?

And any ideas on the over-fuelling?!
 

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Idle rpm should be around 700 +/- 20 rpm

Cheers
 

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Selby - what are those readings? and what are they from? My car is running on petrol - I seem to have run out of gas![/quote]


Those figures came from Faultmate SMV-2 Extreme air and idle page.
There is a Morgan Plus 8 Gems Version 4.70 with all the similar readouts in the troubleshooting pages and a link in another posting recently :?:
 

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Selby P38 said:
Selby - what are those readings? and what are they from? My car is running on petrol - I seem to have run out of gas!

Those figures came from Faultmate SMV-2 Extreme air and idle page.
There is a Morgan Plus 8 Gems Version 4.70 with all the similar readouts in the troubleshooting pages and a link in another posting recently :?:[/quote]
http://www.gomog.com/allmorgan/GEMS/GEMSbyPoole.pdf
 
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