Misfire again

[Martin R]

Geoff, if you could PM me a email address i will zoom it over along with the Excel file

[GeoffSmith]

It looks suspiciously like the O2 sensor Martin, as the output needs to swing less than 1V and fluctuating rapidly as it does nearer the start. My only reservation is that the sensor might not be up to temperature (it can take up to 5 minutes if the engine isn't warm). If you want to send me another run (say 5 minutes or more) then feel free.

Geoff

Elanscan1.zip

[Martin R]

I will see what i can do tomorrow Geoff. Thanks for this. Would it be better if i warm the car up first and then do a 5 min Elanscan run ?

Edit, Geoff i know nothing about this. Ive had a look in the Excel file though and the spark advance also appears to fluctuate wildly at times as well ?

Apologise if im talking the usual crap

[Enright]

I will see what i can do tomorrow Geoff. Thanks for this. Would it be better if i warm the car up first and then do a 5 min Elanscan run ?

No - start Elanscan going then start the car from cold and let it warm up. That will show the operation of the CTS, thermostat, IAC and everything.
The ECU files are usually small enough to email - I wouldn't convert it to Excel if I were you.

[GeoffSmith]

ElanScan is better for analysing data (at the moment) and I can read .ecu files into Excel anyway. The best option is to zip the .ecu file and post it on the forum so anyone can have a look and give feedback.

[Martin R]

Geoff, ive zoomed a longer run from cold to your email. I appear to be useless at zipping and posting

[GeoffSmith]

The CTS looks sensible but the O2 sensor is definitely wrong, however I'm wondering whether this is cause or effect. It would appear that the output is indicating a rich mixture which may be the result of, for example, the injectors overfuelling rather than the output telling the EPU that the mixture is lean resulting in overfuelling. I think it might be worth looking at the injectors first.

Elanscan2.zip

[Martin R]

Could i have your thoughts on the following please ? Ive had all the plugs out and they are all as black as a hat. It appears to be massivly overfuelling as you can now smell the unburnt fuel when its running. Its also running really rough. Could it be the ECU or the fuel pressure regulator ?

[rushing]

Martin
i think and i am pretty sure its the hall effect sensor . replace this and see what happens . i had a year of this misfire poblem and i replaced my hall and it was all ok. the car is running fine now with no misfire . try it . you got nothing to lose mate .
you can buy the hall sensor from any lotus dealer . mine was around £ 20.00 .

[Martin R]

A quick update. Ive resorted to proffesional guidance from a very good friend. To cut a long story short the injectors on 1 and 4 appear not to be working ( dodgy fuel ? ) There is a good spark on both and when you plug another injector on 1 and 4 they click so all appears OK on the injector wiring side. I will change them and let you have an update. Can you get enough movement to change the injectors just by unscrewing the fuel rail mounting bolts or do you have to remove the inlet plenum ?

[Martin R]

Could i bother you all for more advice please. Ive removed the 2 injectors from the Elan and good fun it was
I have a couple of Injectors im sure come from a SE Elan. They appear to differ slightly. A pic.



The one on the left is the S2 injector. The right one the SE injector. Your thoughts please. Does anyone have a spare lying about they could compare with the pic ?
Ive rung SJ Sportscars and they assure me the S2 and the SE injectors are the same. The None turbo are different apparently. I would just buy a couple but at £108 each its not a option when you are unemployed.
TIA

[rushing]

i did all this and spent nearly £600 pounds coils , map sensor , spark plugs , service , cts , thermostat , etc. nearly gave up. could not find out what the misfire was and the engine cutting out problem one of the injectors were blocked and the hall was gone too. cleaned the injectors with one of those injector cleaners you get from halfords where you put it into the petrol.some people do not reccomend this so seek advise . bang the car is running like its had a new engine . A word of advise would be ONLY use reccomended injector cleaners. im no mechanic but this resolved my probelm. Please get more advise from here as there are lots of friendly people who know much more than me about elan diagnostics . good luck mate

[Martin R]

Ive decided to swop injectors 1 & 4 with 2 & 3 and see if the problems move cylinders. I will report back later. It all points to the injectors but i find it hard to believe 2 are blocked Hmm.

[GeoffSmith]

When loosing power comes in a pair,
There is something to be aware:
If the loss is even or odd,
Loss of fuel may be the sod.
If the sum adds up to five,
Sparky bits may not be live.

In other words, the fuel injectors are paired 1&3 and 2&4 whereas coil packs are paired 1&4 and 2&3. If you've lost 1&4 Martin, it would be worth swapping the coil packs over to see if it shifts.

[Sy V]

Fever clucker!

[GeoffSmith]

[Martin R]

Geoff, thanks for that. I have tried the plugs out of the engine and there appears to be a healthy spark. I will swop the injecors around and see if the problem moves. If not i will swop the coil packs next. Is everything hard to access on a Elan though As in being retrained next week full time it will be the weekend before i can get to it.

[Martin R]

A quick update on this as i have had another fun morning on the Elan. Ive swopped the injectors around and it made no difference. The misfire was still on 1 & 4. I then swopped the coil packs around. After a lot of swearing i managed it. The misfire moved to 2 & 3. The coil pack for 1 & 4 would appear to be shot. Strange as with the plugs out the car they both appeared to have a healthy spark. It looks like a new coil pack should sort the problem

Edit, thanks to all who have helped on this.

[Martin R]

Swopping the coil pack for 1 & 4 has finally sorted out the problem. I would like to thank all who have helped with this.
Just for reference the secondary resistance on a coil pack should be approx 5.6K Ohms. I would have tested the primary but i couldnt get a reading due to the small size of the access to the connections. The secondary is the 2 connections the plug leads go on obviously

Edit.

I managed to squeeze a couple of small crimps in the primary side to get a reading.

Primary approx 0.5 Ohms
Secondary approx 5.5 K Ohms.

That suggests to me the primary takes approx 24 Amps, blimey.

[GeoffSmith]

Sounds about right Martin. The current is initially limited by the inductance (few milliHenry) and the current rises linearly (approximately) towards ~10A in a few milliseconds.