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Aug 24th, 2023
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Joined: Dec 2009
Posts: 975 Likes: 20
Talk Morgan Regular
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OP
Talk Morgan Regular
Joined: Dec 2009
Posts: 975 Likes: 20 |
Today I noticed that upon taking away my foot from the accelerator ( and pressing the clutch) the revs came down (as normal) but then gradually increased during a few seconds to about 2000 rpm This happened a few times. One time I saw that the rpm slowly came down again. Also, the normal idle was not exactly stable on one occasion. Engine was warm and running fine otherwise. This is on my 3.0 L 3V6 Roadster from 2009. I did not notice this behavior before. I was in traffic and could not experiment any further, also it occurred only a few times.
Any ideas why this happens?
Thx,
Bert
2025 Plus Six - 1909
2009 Roadster
1983 4/4 4str
Board member Morgan Sports Car Club Holland ('21)
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Joined: Dec 2018
Posts: 779 Likes: 18
Talk Morgan Regular
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Talk Morgan Regular
Joined: Dec 2018
Posts: 779 Likes: 18 |
I had the exact same symptoms on my Nissan 180sx and I fixed it by replacing the plug on the wiring harness that connects to the throttle body position sensor.
I hope that helps.
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Joined: Nov 2015
Posts: 52
Just Getting Started
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Just Getting Started
Joined: Nov 2015
Posts: 52 |
Check the integrity of all the vacuum lines and fittings. A cracked hose can result in unpredictable idling.
regards,
Phil
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Joined: Nov 2015
Posts: 7,894 Likes: 241
Just barreling along Talk Morgan Guru
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Just barreling along Talk Morgan Guru
Joined: Nov 2015
Posts: 7,894 Likes: 241 |
I would start by gently cleaning the Mass Airflow Sensor in some solvent
Jon M
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Joined: Jan 2009
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Charter Member
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Charter Member
Joined: Jan 2009
Posts: 5,879 Likes: 20 |
The electronic throttle is the place to start. If cars arent used fairly intensively you get problems with the throttle position sensor.
Might sound daft but I'd be inclined to sit in the car in the garage engine off, and depress and release the throttle a hundred times just to make sure it was working as well as it can. On the Lotus there was a procedure for re-calibrating it which I think was no more than ignition on but engine not started and pressing the throttle fully open and fully realeased a couple of times. Ignition off then start the engine.
If the problem persists then garage and diagnosticks.
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Joined: Feb 2016
Posts: 7,921 Likes: 217
Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,921 Likes: 217 |
Throttle shaft partially seizing is another one. Usually triggers management light as well though.
Richard
2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone
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Joined: Jul 2007
Posts: 365 Likes: 1
Learner Plates Off!
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Learner Plates Off!
Joined: Jul 2007
Posts: 365 Likes: 1 |
I have the same problem on my 2011 Roadster. The throttle is still cable controlled on these models. Can anybody explain where to find the MAF sensor?
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Joined: Dec 2009
Posts: 975 Likes: 20
Talk Morgan Regular
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OP
Talk Morgan Regular
Joined: Dec 2009
Posts: 975 Likes: 20 |
Check the integrity of all the vacuum lines and fittings. A cracked hose can result in unpredictable idling.
regards,
Phil Well, I thought that this would be an easy lead, so I checked the lines and found one with a kink in it and corrected it by loosening a near tie wrap. Today I took the Morgan to work for a test drive and I could not reproduce the error. So perhaps... this did the trick. Thanks for all the follow up! Bert
2025 Plus Six - 1909
2009 Roadster
1983 4/4 4str
Board member Morgan Sports Car Club Holland ('21)
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