engine rpm lowering and/or stopping

[Gazza]

Found it!

http://wikilec.9600.org/index.php/Tickover

[HJ2]

True indeed, but when you're at it, i would definately do basetiming first

[Gazza]

True as well but I would definitely do revs first as it only takes 2 minutes and you don't get your hands dirty

[HJ2]

Let's talk this one over with a couple of beers!

[dapinky]

To try and stop (or at least skew) the arguement......


.....Base timing *should* be the first thing to check for any malady....

...however, if you have no timing light, or inclination to do the base timing, then it is well worth checking the idle setting whilst waiting to get it to a garage to check the timing, or do it yourself in the future.

Personally, i have a switch in the glovebox which connects the 2 wires instead of having to bend down in the footwell with a paperclip - so getting it into service mode is a 2 second job - one of which is opening the glovebox, and the other is feeling for the rocker switch in the top!

Therefore, checking the idle revs is a 2 second job (using the dashboard rev counter), to adjust it, i would plug in elanscan to get an acurate reading, but for an initial check, the dash is probably close enough - after all, you are looking for a difference in idle speed, not necessarily looking for an acurate number.

If you adjust the idle speed as a 'temporary' fix, and then adjust the base timing, it is worth re-doing the idle again afterwards.

[epipete]

Personally, i have a switch in the glovebox which connects the 2 wires instead of having to bend down in the footwell with a paperclip - so getting it into service mode is a 2 second job - one of which is opening the glovebox, and the other is feeling for the rocker switch in the top!

Now that is cool! Did you splice into the wires prior to the plug?

Pete

[dapinky]

Personally, i have a switch in the glovebox which connects the 2 wires instead of having to bend down in the footwell with a paperclip - so getting it into service mode is a 2 second job - one of which is opening the glovebox, and the other is feeling for the rocker switch in the top!

Now that is cool! Did you splice into the wires prior to the plug?

Pete

Yep - just 2 scotch-loks, a bit of wire and a small rocker switch.

It doesnt interfere with the plug at all, and means i can flip in and out of service mode with elanscan plugged in!

[DeeAitch]

Hello,

one additional information, my mechanics told me that a common fault is due to a small motor or actuator that controls the idle (the air intake valve) , i search for the exact name of this part in the wiki and manual.
Maybe ' secondary throttle vacuum actuator' ??? He showed me a spare (from an Audi) , it looks like a small motor with a shaft to push the valve.
He says that it is anyway wise to replace it after 22 years on any cars so i search for a cross reference, do you know ?

Otherwise, welding the crack of the exhaust seems to improve the smoothness of the engine and decreases poping.

base timing not yet adjusted. it seems to be a bit messy to do it for a non mechanics ???


I shall test more tonight.


Pascal

Probably means the IAC (Idle Air Control valve). Small stepper motor controls the idle, see electrical manual EMK2, page 12.
I've heard it can get gummed up. Been meaning to get to mine as I also have idle issues but it looks to be a real pain to get to.
You might want to try resetting it - details in EMK2 - before cursing access?

[stonefish]

i had the same problem with my elan, the speedo cable snapped and the car kept on stalling when I stopped, the speed sensor is attached to the back of the speedo and is a optical sensor that tells the ecu if the car is moving or stopped I have heard it may be a anti stall device? when I replaced the cable the car ran fine again

[Pascal]

Hello,

next step ... i put the car today in the hands of a M100 specialist who began by a base timing setting.
The Tech 1 read a base timing of 34° (instead of 16°).
The expert had to turn rhe CAS a lot ( more than 10° i would say) to correct. This is a lot , to much to call it simply 'adjustment'.

And then ... it was running worse.

we have a hypothesis :
I face problems since the timing belt was changed. Could it be that the belt was fit with a 'one tooth decay' , and despite this mistake, the car can be turning almost well because the electronics compensates by the calculated timing ?

If i suppose that the base timing was almost correct before ( let's say from 14° to 20°)
if the timing belt is now fit wrong of one tooth, could this be the cause of the very bad base timing up to 34° ?

At the moment, the car has a special setting (smooth, i would say) and will go again to the expert, but your comments are of course welcome about this hypothesis !

Note that the car pops a lot at 1800/2500 rpm... one more information that could be linked to the timing belt / valves position, but i am not sure.


Pascal France

[Pascal]

... i omitted to inform that my "engine stops" were mainly caused by a poor connection of the cable into the speedometer plug (in the dashboard) , so this part of the topic is cleared,

But still the engine doesn't turn has regular as it should, ans the expert said that obviously some power is missing.
The boost jauge shows 0,5 b , it was showing 0,65 BEFORE THE TIMING BELT CHANGE.

Pascal again.

[HJ2]

Good to hear that it was indeed the speedo cable connection at the dash causing the stall problems!
Also good to hear that base timing was tried to set.

One question: Are you sure that the tech guy put the car in service mode and reset the IAC valve before attempting to set the timing? (as per WIKI)
If you are really really sure, than it is not impossible that the timing belt is one tooth out, assuming your CAS has no failures.

Will you be in Ypres now!

[Pascal]

Hello,

Frank Vanherweghe FVH Motors - Lotus Belgium seems to be an expert about M100, he made his engineer thesis on this car years ago, and he has many for maintenance.
My M100 will go to Frank again tuesday , to investigate more, so, some questions before ...

She's poping a lot at 2000 rpm when descelerating, really a lot, more than an old Ducati and more than my mother in law ( although realistic, this reference is likely useless) .
With base timing at 16°, it was really working bad.
At Ypres, it was acceptable with 18° but i had a lack of power ( in fact, Franck made some kind of 'safe settings' to my engine for this day) .

i changed today the (old NGK) spark plugs for Bosch 56 Super 4, i feel it is an improvement but not a solution :
surprisingly , the boost gauge now reaches 0,55 after this spark plug change, while is was 0,49 before. I don't know if this has a meaning ???

two questions :
1°
has someone a recent ElanScan file that could be a reference of a 'normally working engine' ?
( by recent, i mean with the last software upgrade and its numerous informations)

2) Has someone an experience of the consequences of a cracked exhaust manifold , and conséquences ?
there is something on the wiki, but without conclusions.

3°
could my mess find a source in defective exhaust gaskets ? Some of you told me how the turbo was sensible to leakages.


any information is welcome - any news from you also,

Pascal

[HJ2]

Pascal, did you gap the new plugs to 0.8 mm?

[Pascal]

Hello Henk Jan,

the BOSCH super 4 plug is special, with 4 cross mass électrodes around the center pin, and this kind of adjustment can hardly be done.
I choose the most sophisticated choice i found in the wiki topic , i would say.

Note that my old NGK 6 had more than 1,1mm ; although it is written 0,8 in the wiki.

I confirm an improvement anyway, but the increase of boost remains a mistery to me.

also surprisingly , i feel that the poping is stronger now. But better sparkling means better fuel burn so less poping so the problem is elsewhere...

Pascal