Elise S2 111S Idle Issues And Dropping Revs

[glitch]

Ok, so trying my third forum for some help.

Starting to get rather desperate.

A long thread for those that need something to read on Seloc here:

http://forums.seloc.org/viewthread.php?tid=390041

 

Now the short summary.

Bought a S2 111S in october last year, car was acting up on idle and jerking a bit which I noticed only after the deal had been made. Took undertrays off and found oil - fast forward - engine was rebuilt (piston rings were not sealing) here in Sweden by a shop that supposedly knows the most about Lotus K and older.

While rebuilding it was also noticed head was ported. Did not know this before and managed to located last owner in UK that confirm port as K06A port of Dave Andrews which runs on stock ECU.

 

After engine rebuild, the idle is still unstable (it sits fine for a few seconds then drops, then hunts back up and so on). And also at lower revs car is dropping revs. For example, if I go to the throttle body and rev it by hand to avoid issues with cable .etc and keep it steady at say 2500 rpm, it will drop down to around 1200, then hunts back up o 2500 this is repeated in a steady pattern. Looking at short term fuel trim in such a cycle shows it drops to -30 then back up to ~-5 then down and up again in repeated cycles (graphs in Seloc thread). This is felt as jerks at cruising speeds when driving.

 

On higher revs the car runs amazingly and pulls hard to the rev limiter.

 

The guy that rebuilt the engine has asked everyone he knows without any new ideas. Now he said it might be that stock ECU can't handle the port. But last UK owner and Dave Andrews say it should run fine on stock ECU.

 

Here a list of things that have been tried:

- different diagnos tools have been used, "misfire detected" has been shown on some, but no fault code is presented

- new ignition coils and leads

- new spark plugs

- new fuel filter

- new IACV valve

- new TPS sensor, different MAP sensor tried + brown ECU coolant sensor

- throttle closes correctly and opens fully according to ODB

- Emission test was made and passed with good emission values so Lambdas seem to work

- 3 different 111S ECUs have been tried to ensure no ECU issue

- lots of cables jiggled to ensure it is not a broken cable issue anywhere

 

Unfortunately there are few shops that even would consider to take on a Lotus here in Sweden, even fewer that know what they do, and they are far far apart, Current shop considered among the best is 40 miles away. At this point I feel like pouring a can of gasoline on the car....the more sensible alternative would be to actually take a few days off and drive the car to the UK, but recently had a baby so not an option right now :/

 

[jonnyboy]

Get an emerald

[Steve G]

Not sure where you are in Sweden, but my old Elise was purchased by Morgan Hultgren of Bennets Import. He runs a Lotus garage and believe he's the go-to man over there. Think he's based in Lerum if that's anywhere near you. Hope that helps.

[Martin R]

Get an emerald

 

After reading all that thread, this appears to be about your only option. It might be possible to get a loan to try it?

[glitch]

Not sure where you are in Sweden, but my old Elise was purchased by Morgan Hultgren of Bennets Import. He runs a Lotus garage and believe he's the go-to man over there. Think he's based in Lerum if that's anywhere near you. Hope that helps.

 

Hi,

 

yeah Morgan is the one that has my car now and rebuilt the engine. Not near me at all, made the round trip three times this summer....

 

Unfortunately as far as I know, no Emerald dealer close by so I can try and the prices here are ludicrous. One shop that sells Emerald quoted me 1700£ for the Emerald plus install. They are also really far away and have quite a bad reputation. 

What I don't understand why DVA and previous owner would say that car ran fine on stock ECU if this was not the case...

[Martin R]

It probably did run ok before. Has the rebuild changed something? ie cam timing, compression ratio etc. I have no idea and its just a guess?

[Steve J]

Have you checked the intake manifold for leaks / cracks or the exhaust manifold?

[glitch]

Yes - I am told he checked for leaks, as it felt initially like a vacum leak, but did not find anything

The only thing which is different from when I first test drove the car, is that it had a race cat on. When I drove it before I bought I can not recall that it was going so lumpy but it was my first time in an Elise and I was more trying the performance rather than cruising speed.

Then the previous owner put on a normal CAT to pass the emission on the MOT and it was fine, and it was after that once I had collected the car that I noticed it was running poorly.

 

Could it be that for some reason the normal cat is a bit too restrictive and that this is partly causing the issues?

 

Maybe I'll try to ship the race cat to the shop to see if they can test fit it.

[russelld]

I would also try changing both Lambda sensors.

[glitch]

I would also try changing both Lambda sensors.

Hi,

 

but if the Lambda were faulty, then that should show in the emission tests no?

[russelld]

Your poor running problems seem to be in closed loop only. Closed loop is controlled by the ECU & the lambda. I think it would be worth a try before splashing out on an Emerald.

 

I presume you have checked the cam timing and also done a compression test ?

[glitch]

Any good (cheaper) place to by a lambda except elise-shop or elise parts?

[Martin R]

Junks on SELOC normally has one or two new ones knocking about? Try a message on there to him. Good luck.

[Wildspark]

Does the ECU allow the engine to run without a lambda sensor in a get you home mode?

You could try disconnecting it if it does.

[glitch]

Hi,

Car is at the garage that rebuilt the engine far from home so I can't say for sure what happens if lambda is disconnected. Closed loop makes sense, as on first start up idle is fine, then once it warms up a bit the mystery starts.

Rimmerbros did a good price on lambdas so I bought two new ones and sent the race cat to the shop to see if that makes any difference at all. Worth a go. As for ecu 2 others have been tried so all in all 3 and same issues so unless a cable is bad somewhere I suppose stock ecu is fine.