High idle and due for MOT!

[ovi]

Still nobody who also has an increased idle speed?

I replaced the injectors, but nothing has changed!

A few years ago the new exhaust was fitted by the dealer with aluminum tape and was not quite dense so exhaust disassembled and decent mounted so as no more leaks!

As a result, he first run for a long time at 2500 rpm and then drops to 1600 rpm so there is actually something changes but in the bad sense!

Help!

[Brit-Car-Nut]

The most common cause for sudden high idle is a vacuum leak. There are a lot of vacuum lines between the engine and the main bulkhead. You should check carefully for any leaking.

I am assuming the throttle cable is routed correctly and not holding the throttle open a little bit.

[ovi]

No cable is not routed correctly and not holding the throttle open a little bit!
I've spent several hours searching for a vacuum leak but nothing found


Here is a post from 04/2015 so you cab see what i have repaced!

I bought a full throttle body with TPS mounted from my friend Peter who was on an Elan he had just bought for parts and was therefore certainly fine functioning.

Have meanwhile replaced everything whatever I can and I don't hear a small leak anywhere so I do not know.
Some history:
Cheap Scan Showed error 22 (low voltage TPS)
Tried to re-adjust the TPS, but 1500 rpm was as low as it would get. Any lower and the engine stalled.
After That tried another TPS + throttle body, but with the same results (SO ... NO results ...)
Then Replaced the CTS, but without any luck, no result
Replaced MAT: no result

Yesterday I received the new IAC valve from SJ and mounted but the result remains the same!
So I keep searching.

[Giniw]

As for the leak test, what is your vacuum pressure when idling? If I am not wrong, it should be around 0.30~0.31 bar (absolute).
Do you have an elanscan log for us to read? (maybe I read the thread too fast but I couldn't find any)

[ovi]

If HY2 come again to visit we will certainly do a elanscan.
Could it not be that the oxygen sensor does not function properly?
Outer than the problem with the idle it drives great and has also full power so I do not understand?

[s1ghthound01]

Hi, I had the same issue after fitting new injectors, new CTS sensor etc. Then read a report that if you switch on your ignition, turn the throttle at the throttle body by hand full rotation 5 times, switch off ignition and remove the key, wait 40 seconds then start. This apparently resets the ECU to the fuel required by the new injectors. I have just done this and my M100 is now ticking over just fine, accelarates fine, no popping back through the exhaust on deceleration. Result I hope.

[HJ2]

topic resurrection!

Can anyone confirm the above procedure?

[Giniw]

Well I would tend to think that it can't do anything different than disconnecting the battery. Maybe that procedure resets the BLM or something similar but, disconnecting the battery resets it too. (There is an ALDL command to reset the BLM too but elanscan doesn't implement it if I am not wrong)

[Steve A]

I just disconnected the battery to reset the ECU after changing my injectors
although the revs are a bit high when I first start the car and until it starts to warm up

[Giniw]

What RPM is a bit high to you?

[Steve A]

What RPM is a bit high to you?

I'll take note the next time I'm out, it's high enough to rev up when you change gear though

[HJ2]

So more than 950-ish rpm.
I currently have the same. Smells rich as well

Can it be this simple?
I just disconnected the battery. I will see in the morning what it did

[Giniw]

I asked because of course it's normal the engine is around 1200 RPM when cold at tick over, and I think it can rev even more when the weather is very cold (about 2000 RPM I think).

it's high enough to rev up when you change gear though

OK, so that would be a lot to me!

[Steve A]

I asked because of course it's normal the engine is around 1200 RPM when cold at tick over, and I think it can rev even more when the weather is very cold (about 2000 RPM I think).

it's high enough to rev up when you change gear though

OK, so that would be a lot to me!

It's definitely higher than it used to be

[HJ2]

then don't rule out the coolant temperature sensor just yet...

[Simon_P]

Closed loop or open loop?

Have you checked the idle in service mode?

[Steve A]

Closed loop or open loop?

Have you checked the idle in service mode?

Closed and yes

[HJ2]

Well, I fixed mine:
I wanted to replace some vacuum tubing to see if that would cure the high idle when cold. When i removed the wheel arch liner to expose the vacuum reservoir, the ' big' hose practically fell off!

All fixed now and idle is back to normal