Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) High Idle speed when car is moving

I wonder what Ledgerwood's reset involved

Yes it does sound like anti-stall, Senses forward motion and applies throttle. Clutch ECU control switch could also be faulty, they are very fragile and cheap unfortunately and can cause quite a few odd symptoms. check electrical plug connections first though.. You may also need to take a closer look at the throttle control butterfly as you may have some leak by (air wise) through either distortion or loss of the sealing adhesive they use to take up the gapping around the seal to the butterfly and body. Yes, its hardly a thing of engineering prowess and in truth resembles a jim crack amateur repair solution! Check also the band clips that hold the rubber ducting to the hard plastic body of the T.C.B. if this has been overtightened it can distort the body thus restricting the butterfly from fully closing and the air will be able to bypass this and tell the ECU that throttle has been applied. However this will usually show as rev hang. But when stationary the idle control setting will regardless of air by-pass, within reason, by way of throttle potentiometers drop to idle speed.

So, remove the throttle body fully and check the butterfly seal to body using a light behind it, there shouldn't be any creeping through! If there is some distortion and subsequent light pollution check patency of body,spindle and butterfly flap. If all good then place the throttle body somewhere warm, oven at around 50'c for half an hour an see if that lets the body relax from overtightened band clips. Clean the whole thing and lightly lube the spindle ends. reinstall when you are happy that it is functioning as it should. Do the same with the MAF, check function and electrical contact/plug. So many mechanics over tighten band clips, they all get tightened to water hose tight!

Often a problem will be the result of more than one single issue and that is why it can be difficult to isolate what is wrong. Unfortunately I find the Morgan to be the absolute worst example of this and is a nightmare to live with in that respect. It's fundamentally a kit car where nothing was actually designed for the chassis, it was rather made to work yet without the thought of the environment it was being used in as opposed to having been designed for!
Tips:
When reinstalling the throttle body or MAF control body just tighten the clips enough to hold it, this will probably feel under tightened to you but you will feel the band clip go tight and then stop! Loosen and tighten a couple of times and you will feel what I'm getting at.

At some point its worth pulling all the electrical connectors apart and checking for corrosion. clean with something like de-oxit spray, its remarkable stuff and really works on fragile connectors without poking at them! Lots of electrical issues in a classic are caused by these poor choices of connectors and electrical connections.

Don't use these connectors in exposed areas you will see stated on packaging and instruction manuals yet Morgan seem to insist on them. Basically they have put non sealed electrics in what is something like a boat! so you are going to get trouble aren't you!

So in conclusion, good luck and don't lose heart, suspect more than one issue to be causing your problem and every time you do any work on the Mog take the opportunity to carry out preventative maintenance work!

Yes Richard, I was wondering that as well but dismissed that thought when it clearly hadn't worked!

I know my 94 +8 is not the same set up but when I had a similar issue it was the Road Speed Sensor not talking properly to the ECU causing the ECU to over compensate. Ended up being a dirty earth as usual.

From memory I think it was a smaller orifice plate to sandwich between the Idle Control Valve, a bit of a bodge and not sure how well it worked, someone used to advertise them in Miscellany