Using elanscan

[Fredjohn]

The O2 sensor replaces the blank threaded plug (bolt) just to the left of the turbo, sticking out of the heat shield on its left, in front of the dipstick.

I have yet to do it, but it is often seriously stuck and requires lots of WD40 or equivalent, lots of effort and lots of muscle to get the old blanking bolt out.

[Chas54]

SO . brakes bled and I cleaned the little breather box filters etc and checked pipe work. Took off the CO pot cleaned the terminals with a magneto file and tweeked them a bit so they engage better with the female plug. With service short on I managed to get the CO down to 2% again , I took the short off and the meter stayed around 2%. I dissconnectd the battery terminal and left it for about 20 seconds. Alarm going off etc. The pot adjustment is at the lower end of its range as I set it at about 650ohms when I installed it and only screwed it about a turn when trimming the CO. Based this on the advice anticlockwise is weakening the mixture.

On reconnection , entered the immobiliser code and went off for a short run at 30mph. pulled up back at home , and the idling engine is running really rough . In fact it sounds so rough I suspect the timing- although I set the baseline timing a couple of weeks ago, I am going to recheck it tomorrow. I suspect the ECU is altering the ignition timing for some reason, the baseline timing should still be OK .

Ive made up an elanscan cable but it wont recognise port - I think I had to do something with data speed on the previous one I made.

I will post an elan scan print once I get a connection.

I thought the big bung on the blower was too obvious and not occupied by a sensor on the inner wing picture.

regards

Charlie

[dapinky]

Charlie,

The picture is from my red elan which I kept as open loop, so there is no O2 sensor in the photo.....

..... but it goes where the big bolt/plug thing is on the exhaust manifold. If you look at the picture, there is a big bolt head (32mm??) visible through a hole in the turbo heat shield, just to the left of the inset word "turbo".

I would suggest that you plan ahead as the bolt is usually a bit tight (understatement!) - genearlly accepted wisdom is to spray the bolt with plusgas (not WD40) or other releasing agent on a daily basis for about a week before trying to undo it - then grab the longest bar you have, even stick a scaffold pole over it for extra leverage, and then give it a nice steady pull. Once the rust seal is broken it will come out easily, but it takes a good effort to break that seal.

Even if you decide not to fit an O2 sensor, there is no harm in planning for the future.

[Chas54]

Elan scan cable fixed with new £3.5 chip off e bay. May collect some data tomorrow now.

I will look into freeing of this large plug , as you suggest , plan for the future.

I am still not convinced I have done a proper reset of the engine management system .
I got the CO down in service mode . The engine light flashing etc . Pot adjusted , idling well.
I remove the short from the plug, CO still ok. Stop the engine wait a while , disconnect the battery wait about 20 seconds and reconnect. Then go for 30mph run , pull up and the idlings so lumpy its almost like its missfiring.

I will have to check the IAC position again . I am wondering if I cant get it to 20 when idling, there may be something wrong with it. It looks a bugger to get at though.



regards

Charlie

[Saltire]

Charlie, the red car shown in the picture in the comment above doesn’t have an O2 sensor. The sensor screws in to replace the large hex-headed plug which you can see to the immediate left of the “Turbo” wording on the heat shield in format of the engine. Then the wires connect to the pigtails on the O2 sensor.

You may find that the existing plug is extremely tight. When I replaced my O2 sensor recently (S2), it took copious amounts of heat, PlusGas over several days, and the correct socket before I could - eventually - get it to budge.

Good luck!

[dapinky]

Keep up at the back, Jonathan!!!!!!!!!

[Simon_P]

I am wondering if I cant get it to 20 when idling, there may be something wrong with it. It looks a bugger to get at though.

Ignore the IAC it is just a stepper motor and yours appears to be working well. When you set the idle in service mode the IAC valve is positioned at 20 clicks, you adjust the air bleed so that the revs are the same and therefore you should see 20 clicks on elan scan. You have 15 so something is amis. Go by ear for the revs when setting it.

Simon suggested the crank breather contraption as a vacuum problem if incorrectly plumbed and I just pulled the vac side hoses off and didn't get a change of engine tone. Ill have to have a look at it I think .

I suggested the Evaporative Emissions system which is completely different. You won't get a change in engine tone unless the vacuum leak is so large that the IAC can't cope - you pull the hose off the ECU closes the IAC... it's you vs a computer unless it's in service mode.

You won't see any effect from the crank breather as it is already bled through the PCV valve.

Not sure if it's been mentioned but there are 2 versions of CO pot as well as 2 versions of memcal.

Only adjust one variable at a time.

[Fredjohn]

Jonathan: thanks for confirming and clarifying my earlier post

Dave: well spotted

[Chas54]

Thanks guys for all comments.

Ive run the car from cold at idle this morning and collected the elan scan data.

I can see the IAC is still not reaching 20 at idle though.

More alarmingly , for me anyway, is at about 500seconds the ignition advance takes a wander , it looks like it goes up to 30degrees BTDC .
I cant see what this corresponds with and having set the baseline timing the other week, I am sure it is either the ECU doing something I can't see, or a mechanical failure of the hall effect device .

I finished the idling run with a short spell at 1500 revs after the fan cut out.

Hopefully I have posted the data here.

I am intending to return to service mode this afternoon and try the IAC adjustment , battery disconnect for a reset , and then try a short 30mph run with the laptop plugged in.

I hope I am exiting the service procedure correctly ? I finish the adjustment , remove the short at the service plug and then stop the engine. I then disconnect the battery , put my fingers in my ears for 20 seconds while the alarm screeches, then reconnect the battery.

results later I hope.

Regards

Charlie

[Chas54]

I forgot to say, thanks Simon, I was mistaking the crankcase breather for the evaporative emission control.

I am not sure what that is though, I had made an assumption that it was something to do with air conditioning , which I haven't got .

I may have to go back to the manual for a look at it

regards

Charlie

[Chas54]

Guys,
Here is the elanscan data from my short test drive after reseting from my idle air adjustment this morning

I can see the IAC nearer 20 now but, I'm still nowhere near with CO on my meter 6.7%

There's also more movement in the ignition advance than I would expect ??

Any comments much appreciated.

Regards

Charlie

[Chas54]

OK ive adjusted the IAC screw in service mode , done a reset and gone for 8 mile drive around 35 mph.
Return home and looked at the elanscan data. The IAC is now at 20 in idle.

So re enter service mode , adjust CO pot eventually getting around 5-6 % .

Carry out a reset ( battery disconnect) go for a short drive and elanscan data shows IAC now 13 at idle . Shorter drive though.


Now I am confused again ?

Any ideas what ive done wrong ?

Heres my two scans

Regards
Charlie

[Saltire]

Jonathan: thanks for confirming and clarifying my earlier post

Dave: well spotted

Sorry guys, cross-posting. I’ve been away at a wedding this week and I thought the posting had transmitted from the phone when it hadn’t.

Either that or I’m losing my marbles . . .

[Simon_P]

Any ideas what ive done wrong?

I just spent some time looking at your scans and comparing them to known good ones. Both open and closed loop, I was looking at injector pulse width as you are adjusting CO - they are all within the range of 145ms to 150ms. Your first scan was 145ms which is logical if you think that it has been passing MOTs for 25 years.

Since you have adjusted it it is now down to 128ms. What I think has happened is that the you have unintentionally switched from trying to find the problem to trying to adjust it out. The underlying problem is still there.

I suggest that you go back to the original CO pot position and look for the cause of it becoming too rich. Fuel pressure regulator, leaking injectors etc.

[Chas54]

Simon

Thanks for taking time to look at my scans. I think you are right that I have switched from finding the fault to adjusting it out. I have had the car three months and when I bought it (72000miles) , it ran well but did smell a little rich.
It started running a bit rough a month later and I found numerous leaks on perished vacuum pipework and the MAP sensor wouldn't read. I changed the MAP sensor and the new one reads OK on elanscan and improved the running.

My MOT at the start of August revealed the high CO , which I had expected with the rich smell of the exhaust. I have made an assumption that the previous MOTs passed OK but the sealed blue CO pot had been adjusted before and the IAC screw cover also came of easily enough. The car had been regularly serviced by a Lotus specialist in Maidenhead. The servicing records are good and the chassis suspension etc well waxoiled , so I don't doubt the standard.

I have just had a look at my scans again and I can see that on the one yesterday marked ( elanscan IAC 20) , this was where I had adjusted the iAC screw and had adjusted the CO pot to give me 2% idling.
I can see the injector pulse width was reduced .( Ive found how to adjust the graph axis on elanscan) At the end of this 8mile drive the IAC was at 20 but the CO 8%.

I cant figure out why when I next run the car (elanscan Lepe), after adjusting the CO pot and doing a battery disconnect reset, a short run of about 4miles , the IAC has altered to 13 idling, CO still high.

I thought that as the IAC position at 20 had been "learnt", and the fact I didn't adjust the screw position, it would stay learnt at 20. It seems it was relearnt again at 13. Would it be likely that my CO pot adjustment would cause this alteration in IAC position ?

Anyway, despite this, I am taking your advice and I will adjust the CO pot to give a slightly higher injector pulse width. Also I am expecting delivery of the new chip 9930 from SJS, but I don't think I will install it until I have found my underlying problem. So today I will have to trawl through the CD version of the manual for information on testing /checking injectors and fuel reg .

Thanks again for your time and advice. I have been really struggling to understand the electronic concepts of engine management.

Regards Charlie

[Simon_P]

Yes power output varies with AFR so adjusting the Pot will change the idle speed which the IAC will correct - I'm not saying that is the cause of your readings though.

In answer to your earlier question - once set you can pretty much ignore the timing. The ECU adjusts the timing and what you are actually seeing is what advance it has requested.

[Chas54]

Thanks Simon.

I think I have figured out how to test the fuel rail pressure and hence the regulator valve but I cant think of an easy way to test injectors. I can probably test each one for leakage via an air line and watch any pressure decay . but fuel delivery of each for comparison of fuel volumes may be tricky. I may have to take the injectors for a test somewhere .

I have referred to my electronic copy of the manual , but I have some pages missing.. If I have read this correctly , I don't need to do an ECU reset after a CO pot adjustment .

I am trying to cut down the noise a bit, I don't want to annoy all my neighbours to much with the constant car alarm when disconnecting. .



Regards

Charlie

[Simon_P]

John BCN wrote about testing the fuel pressure regulator some time ago and I think there is a video about testing injectors. You could also try injector cleaner as I believe our design of injector is susceptible to varnish.

[Chas54]

Thanks Simon

I have done some test of the 2ndary throttle vacuum today , mainly to see if there was any air leaks. I do have a problem gaining sight of the throttle linkage, actuator and reservoir .
Ive groped around the rear of the engine trying to feel for the reservoir and actuator and cant reach any. Test was only really testing up to the solenoid by sucking pipe and noticing when solenoid opened..

I have a manual car lift so with the car completely in the air, I can sit underneath but still cant see the bits. I guessing the only real way is to remove the inlet plenum chamber.

1st sept 2019 test drive.zip

(60.92 KiB) Downloaded 640 times

I have readjusted the CO pot and got back to about 1.4 ms injector pulse , CO reading around 7% . still high. After doing a reset i have had a drive round and the IAC position on idle is now 19.

I had a look at the fuel rail and injectors and the test methods , but have done nothing yet as i thought i might try some injector cleaner . So 1/2 a tank of 97RON petrol (E5 though) and a tin of snake oil.

Ill do some mileage this week and see if i have any improvement. I think i still need to screw the CO pot in a bit more to achieve the 1.45ms .

In my manual, there are two sections dealing with CO pot adjustment, the first doesn't make any reference to being in service mode whilst the second does . Ive made an assumption that i would need to do a reset.

Ive attached my latest elanscan result . I have spotted a couple of point on a very slow drive when the inlet manifold pressure appears to go +ve.

Any comments welcomed

regards
Charlie

[Chas54]

Hello guys.

I have just received and fitted my new 9930 memcal to replace the original 9929.

Whilst fitting it I noticed that during my previous numerous adjustments to the CO pot, I must have backed the adjusting screw nearly all the way out as it had dropped off. I know what the resistance range is but I have been wondering what a reasonable starting point would be to set the resistance to, prior to refitting the pot. I know it will need further adjustment when in and warmed up etc , but a starting point would help me. There are no stops on the pot but the highest resistance is around 10kohms screwed inwards and around 400ohms fully out to the dropping out point. According to WIKI unscrew Hence lower resistance is weakening and screwing in ( higher resistance ) is enriching the mixture . Almost sounds the wrong way round to me ?

Any estimates welcomed.

STOP PRESS:- I took the pot off wound it to minimum on the bench - about 270ohms. The screw that fell out isn't actually the main adjuster, its only an extension, a little stainless tube is under the head and inside that is a bar that engages with the actual pot screw, further inside the resistor.

Now at the minimum I thought I would screw in to increase but CO goes up straight away. So I'm at 2% which has eased worries a bit .

I am still concerned that I am on the minimum point and wonder if the injectors are passing slightly or the fuel reg is sticking , leaving the rail pressure high. Just as SimonP suggested. I am hoping the fuel cleaning jollop will work its magic .

Thanks for suggestion . They are a great help.


regards

Charlie