2006 Exige S

Yeah I’m guilty of calling every circuit “my favourite”, but Donny is very much up there!

Anyway, onto Saturday and a visit to my favourite circuit ( :mrgreen: ) - Blyton Park

It was a Javelin day, so was expecting some crowding but I had a few friends travelling over in their Lotus’ and I’d arranged a friend and fellow enthusiast to join me for the day for some tuition. I did the same a couple of years ago and my tutor for the day (Ishy) really helped me move my game on along both with Blyton circuit knowledge but also technique knowledge that I could carry through into future trackdays. Unfortunately a year of no tuition thanks to COVID meant I’d regressed a bit so I was looking forward to a refresher session.

For a Javelin day it was very quiet right from the get-go. Paddock seemed busy enough, but for some reason the track never seemed to get busy. I wasn’t queued up a single time and I got loads of clear laps in, perfect.

First session was just me finding my feet and remembering where the track goes, second session Ishy took the car for a few laps as I wanted him to give me some direction on damper tuning and whether the car had any obvious scope for improvement.

One thing jumped out in that the car would push a little bit in slower corners which is fairly standard behaviour for the S2 Elise/Exige platform, but where he expected this understeer to continue through to higher speed stuff it didn’t, and instead the front of the car came to life and the rear got a little bit loose.

This was knocking my confidence a little bit in the quicker stuff because I wasn’t sure the rear of the car was going to live with a higher speed turn-in (you can tell on my recent videos that this manifests of turning in way too early to almost all corners, and of course carrying less speed). We discussed a couple of theories for it, one being the extra camber I’ve added to the front potentially unbalancing the car a bit in conditions where that camber really comes alive (the faster/higher load turns) and the other simply being damper tweaks. I

I’ve always had a very simplified view of damper and/or ARB changes in that:

  • If the front lacks grip, then soften the front or stiffen the rear
  • If the rear lacks grip, then soften the rear or stiffen the front

Ishy explained the logic behind that, and why I may actually want to consider the opposite. I probably won’t do his description any justice but he put it in terms of the car generates most grip whilst the suspension is compressing. Once it’s maxed out it’s compression, then grip stops increasing. With that in mind, softening a car can help because the compression will effectively start with less weight transfer so the theory I worked to has some sense.

The counter theory he put to me is that my car is generating enough grip that the range of compression is actually running out, and perhaps by adding some damping we could prop up the spring rates a little bit to delay this limit from being reached - at the trade-off that my transition between grip and no grip would become narrower.

Going forward Ishy would be making some ‘blind’ tweaks to the car so that I could give unbiased feedback, a little unnerving at first but this worked really well and I think between us we got the car into a much better spot. I don’t actually know what damping settings I ended up with, I need to go into the garage and document them - so reminder to myself. We did end up going stiffer over all which brings my dampers very close to their stiffest settings, so I’m running out of adjustability and some slightly stronger springs may be worth consideration.

We had 3 or 4 sessions on the run up to lunch, car (and me) got faster and faster. Particularly around the Port Froid high speed chicane type thing which is the type of corner that has been bothering me all year. Jim Clark Esses (Croft) and Craners at Dony have all exposed my lack of confidence in the car - but we were gathering pace through Port Froid at a pretty impressive rate. Ishy suggested just before lunch that we’d be taking it flat by the end of the day…

Unfortunately, we never got to find out. The car was on fumes at lunch time so I limped it into Gainsborough for a fill up of Jet Super (97). The usual favourites of Shell and Tesco (Momentum) are really hard to get hold of around Blyton so I’ve always used this Jet over the many trackdays I’ve done there. The pump seemed very lethargic in delivering its fuel, took ages to give me the 35litres.

Got back to the track, had a quick brief with Ishy and they we headed out to keep on pushing… but the car had called it a day :frowning: It wouldn’t rev above 3k, was heavily missing and sounded really lumpy at idle when we brought it back in.

Laptop out and I could see it was running very lean, at idle it was only making around 1.4 Lambda (target of 1.0) and you could hear it struggling as a result. Blipping the throttle would lead to heavy misfiring and an attempt at stalling. On the road I could creep the revs above 3k if I was VERY gentle on the throttle, but any sudden load or requirement for fuel and the car would stutter like mad.

I suspected dodgy fuel, and still do. Investigations still ongoing but it was a disappointing early finish to the day. Track continued to get quieter and the weather was perfect. I made the most of the day, had my first ever track experience of an S1 Elise (from the passenger seat) and that was eye opening. Braking distances are another league completely, it felt like an absolute hoot despite its 140bhp.

I limped the car home, whether that was a mistake or not is yet to be discovered. I could see some knock events in the ECU logs after I got home, all at very low ignition advance and low load (sub 30% throttle etc) so hopefully it’s not “dangerous” levels of knock - but still very much lends to the theory that the fuel I’ve put in is complete garbage.

I’ve not done much so far, just taken charge cooler off for access and pulled the injectors for a look of anything obvious.

Injectors were next up on the roadmap for upgrade anyway, so they might get swapped out whilst they’re accessible just to rule them out. I’ve also spoken to Spitfire who make my fuel pump who have given me some metrics to gauge how well the pump is (or isn’t) working once I can drain it into a bucket so the plan is to disconnect the fuel rail, set the pump running from my ECU and drain it all out - put it all back together and stick 20l of v-power in and see if it magically comes back to life.

Small update, I drained the tank (pretty easy via the quick connector near the header tank, good tip Dave) using my ECU to override the pump.

Gaz at Spitfire have me some metrics for flow rate which the pump exceeded, but I still could do work a pressure gauge to make sure it’s not struggling under pressure… But I think the FPR is inside the tank on these cars so perhaps that test is redundant?

Anyway, I stuck 20L of vpower in with some redex snake oil and fired the car out. I wasn’t expecting an immediate fix due to fuel in the lines etc but I was expecting a fix over 20mins or so… Which didn’t come :frowning:

It’s now idled for about half an hour over two 15min sessions. Only real observation is that the lambda starts a little richer when the engine is cold (1.2) and leans off to 1.4 or so as the engine warms up. Still miles off the 1.0 target.

I’ve done a few basic misfire tests, pulling coils in turn but there’s nothing really conclusive.

I’ve decided to order some new injectors, really little point in getting mine tested/cleaned as they’re on the retirement list anyway. Hopefully they sort it, but this last 24 hours seems to have killed the dodgy fuel theory.

If injectors don’t fix it, I’m going to start struggling where to go next tbh. Compression test? Any other barrels to scrape?!

I havent investigated too many things with the 2ZZ engine but typically on a Renault we get hesitation and missing like mad when

Plug gaps are wrong
TDC sensor is kaput
Something relating to the boost control ( normally N75 valve ) is faulty.

Check fuel pressure. Open flow is almost irrelevant,

Cheers Andy, can’t rule anything out - I still feel evidence is pointing to fuel delivery but it’s getting to the point where I can’t exclude anything.

Thanks Dave (and the follow up phone call!), we’ve got a plan now to troubleshoot this pump and prove it. Flow tests are only half the story, but plan is in place to check the rest. Seems I’ve got a busy few days coming up :thumbup:

Pulled the plugs at lunch time just to see what’s what. I did pull them at Blyton and they all looked quite white, but one of them is now showing to be a little sootier. Not really sure this means anything, but I have some spare plugs knocking around somewhere so I’ll rule them out - just cos’.

Oh, and my new injectors arrived. Think I’ll pull the pump first and do a pressure check before I fit these, as the ECU will need some tweaking to handle their higher flow rate.

On a brighter note, these should keep up with a few more PSI of boost when all this is over :wink:

Plan for tonight is to get the roof off, interior out and pump out. Give everything a good eyeballing and then see about setting up a proper test bed with a fuel pressure gauge to make sure it’s actually making what it should be.

what are your plugs gapped to?

I checked last night and they’re in spec, whatever ‘spec’ is - my notes are in the garage and it smells of petrol too much for me to go in there this early on a morning :mrgreen:

Last night I ruled out plugs, coils and injectors completely. I had some spare plugs and coils knocking about (I’ve got far too much 2ZZ stuff…) which I fitted in turn, and I fitted my new 550cc injectors.

This puts me back onto fuel pump investigations, so late last night I took out the car interior and lifted the pump. I was really hoping to find a smoking gun, tank full of crud, black filter, SOMETHING! There were a few bits of crud inside the tank from what I could see, talking 3-4 max. The base of the pre-filter is a bit dirty but I’ve seen far worse.

Plan is now to pressure test the pump and see if it can actually flow fuel properly when it’s under pressure, rather than just the open flow test I did before.

It looks like the car is now fixed, still have to put a lot of parts back onto it but with (a lot of) help from SeriouslyDave, it looks like the issue was related to my fuel pump.

I took the pump assembly to Dave as he’d kindly offered to lend me the use of a fuel pressure gauge, so using a bucket and some butchered hosing we setup a test rig.

We were aiming for 3.25bar in accordance with Toyota specs, but at barely 2bar my pump assembly was venting fuel back into the bucket. Initial thoughts were the FPR failing, but closer inspection showed the fuel coming up from the union between the pump and the filter housing. Hmmmm. We repeated the test on an OE pump

I need to put in a massive disclaimer here: The night before I took the pump assembly to Dave, I dismantled the assembly on my bench just to check for anything obvious. The only thing I really noted is that the pump ‘fell out’ of the filter assembly easier than I expected, after I pushed it back in - it felt a bit more secure. Me putting this assembly back together may well have caused some of what we went on to find… so keep that in mind.

We split the assembly apart and since Dave has a massive array of Lotus/Toyota OE parts on the shelf we were able to compare against a standard unit.

Missing is the white spacer that sits between the seal and the main pump body, this prevents the seal from being pushed down over the nozzle of the pump. I ran this by the vendor of my pump who confirmed that the spacer is missing intentionally and that it shouldn’t be needed if the seal is fitted dry and lubricated externally.

Also the seal (not photographed) had ridden up the outlet nozzle so it looked something like this:

(green is seal, red is spacer).

We refitted the seal, and nicked an OE spacer (I.O.U Dave), put the pump back together and lo and behold it held close to 4bar with no drama.

I brought the pump home not totally convinced we’d fixed my problem, I was pretty sure that the out of place seal was purely a result of me rebuilding the pump the night before, but after refitting the pump the car fired up and idled perfectly. Fuelling right on target and will rev up a treat, no more misfiring or stumbling.

So bit of an odd one, all I know for sure is that the car didn’t work last night, and it works now. All I’ve changed in that time is removing the pump and adding the spacer/refitting the seal. Maybe bouncing on the Blyton curbs (or more likely, the potholes on the entry road!) caused the pump to push beyond it’s seal? Seems like a long shot, but it works now but it does seem completely unrelated to the Jet refill I had at lunch, so sorry about that Jet :laughing:

One fact, this would have been a nightmare to find without the help of Dave @ SeriouslyLotus. Knowledge and tools are only half the story, but having the sheer range of parts available on the shelf to inspect/compare is absolutely invaluable. This is the second time Dave has bailed me out this year under very similar circumstances, previously helping me to prove to Competition Clutch that my pressure plate was faulty by comparing to his stock. Considering Dave offers service/maintenance/hands-on services, I feel he’s gone out of his way (twice!) to help out a DIY’er, can’t really ask more than that. Cheers Dave :thumbup:

Great news! You’ll be down at Caffeine & Machine, then ?

Good stuff and top detective work from yourself and seriouslylotus

thommo Ollie sorted you out? :wink:

Great work Kyle, so good to see it back in working after trying all these things and it turning a blank every time!

As you said huge kudos to Dave seriouslylotus - he had no reason to help you out and still did it giving up his time - great to see and something he really didn’t have to do!

Great detective work and kudos to Dave for assisting again.

He really is a very nice man,

Yep, all sorted, thanks. Looking forward to Sunday

Doubt it mate, car is in a million pieces still :frowning:

Shame, but glad you got to bottom of problem.

Back to Blyton last weekend for some unfinished business.

After fixing the fuel pump issue, I had the car in a few million pieces so I used the opportunity to whip my dashboard out and terminate some new wiring which I’ll use later, maybe.

The Dashboard has two ‘switch to ground’ outputs on it which can be used for just about anything you can think of. I have a plan for one of them, a gearbox oil cooler. This switch to ground can be used to trigger a relay when my gearbox temps reach a certain level, which will in turn power a pump. Not sure about the other one yet, but I’ve run them both to the boot anyway so I can decide later. The other wires are for a 3pin sensor which will most likely be fuel pressure. It annoyed me a bit that one of the few things I don’t monitor caused my issues, so at least I can cover it off for any future mishaps. The sensor is connecting to the dash because I’m out of capacity on the ECU itself, but I can forward the fuel pressure data over the CAN network so I can still use it for corrections, limp home modes, etc.

Having the interior out allowed me to run neatly up the gear lever surround, up the rear bulkhead and out through an existing grommet.

Dash is pretty dinky when out of its surround. Lot of nice gubbins tucked into that wee package.

I made the decision to not refit the rear bulkhead plastic trim. It serves a function of holding the rear speakers and the interior light, but I’ve long since retired the rear speakers and the hassle of inspecting/servicing the fuel pump is increased tenfold by the presence of the trim - so it’s staying out for now. I would like to smarten it up and trim it a bit maybe before reintroducing it. Maybe a winter side-project.

With the seats back in, you really can’t tell it’s missing.

One final tweak was to put the front ARB on the stiffest setting. From feedback from Ishy, he expected a negligible improvement, but at least no downside - so no reason not to set it like this.

Onto the trackday, Ishy had kindly agreed to join me again - he was Southbound for Hethel on that day so he came in his Exige all kitted out for his trackday the day after.

The day was well run by TrackObsession but I’m fairly sure the universe conspired against me having any real clear running. I’ve never known a day at Blyton like it! It wasn’t obscenely busy, but every time the traffic parted was for me it would either get red flagged or start raining. It started getting silly when I finally got some space out in front of me, got my head in the game for a hot one - then had the black flag thrust in my place to be then told (oh, wrong Lotus. lol). Then on another occasion we were attacking Port Froid a bit, so making some space, going at it and altering lines etc - but kept catching up to the car in front. He finally let me passed, then saw him clip the cone at Port Froid in the rear view mirror leaving it right in the centre of the racing line - so my next lap was compromised by that anyway :laughing:

Despite the complaints, it was still very productive and more importantly the car survived all of the sessions with no hint of the fuel pressure issues returning.

I felt we made great progress on the first corner (Jochen?), Bunga Bunga and Port Froid. I frustratingly never got Bishops right all day… seem to have gone backwards at that corner, but it’s robbing me of a good lap now.

Ishy kept contributing to car setup tweaks, and we found ourselves running the rear dampers on their stiffest setting by the end of the day. Trying to prop up the rear a bit on the fast direction change of Port Froid, and ideally we would go stiffer still as it wasn’t really compromising us anywhere else, even in the damp the traction was fine in slower corners. Looking like an argument for some stiffer springs I think, but need to check with Nitron first whether my valving is suited to it.

Oh, I also had some new dash layouts for the occasion. Spent a lot of time making very minor tweaks and tidying things up but I’m getting close to something I’m happy with… until it all changes again.

Road:

Track:

Fantastic write up. I feel I am several steps behind you in the evolution of my car so its great to know a tried and tested path :thumbup:

For the first time in what seems like ages I took the floor off the car for a bit of prep before my next trackday, this weekend at Lotus HQ Hethel.

Quick oil change, keeping my 100% record of making a mess of the garage floor in the process.

Followed by a general spanner check, I did notice a couple of things - some loose fixings, hose popped out of its clip, usual Lotus things :unamused: Something I did notice I hope will be significant though…

I took the car away for a weekend a few weeks back, one of the first times in ages I didn’t drive the car with either a helmet on or earbuds in and I felt the gearbox was feeling a little noisy when coasting. Box has always been a bit noisy, partly due to the harsher mounts I have fitted but I couldn’t help thinking it was louder than usual.

What I found under the car was the dust shield from the half-shaft part of the OS driveshaft just hanging loose:

It should be just an interference fit onto the flared end of the driveshaft, but it’s popped off and has been bouncing around on that shaft for god knows how long. Because it’s worn itself down a bit, it won’t fit onto the flare anymore, so I’ve blobbed it on with araldite until I can get the shaft out and address it properly later on. Hopefully that’s the source of my rattle, but we’ll see.

Final tweaks made to the map, since I’ve been using AC a lot this year I’ve noticed a few things that weren’t apparent last year, mainly around idle compensating for the additional load generated by the AC compressor. Worked on some correction tables and got the idle nice and stable with the AC running.

That’s about me prepped, I’ve had a kind offer for somebody to take a spare set of wheels down for me so I’ll drive down on my AD08RS and have them as an option if it’s damp. ZZRs will go on otherwise.

On the note of taking cargo, we’ve swapped the daily drivers around a bit and we have a possible candidate for a tow car

Within days of buying it the Government lifted the requirement for us younguns to sit an additional test to pull a trailer, so I’m a towbar away from being able to give it a try. Scary :laughing:

Hethel Update

Attended a trackday at Lotus HQ last weekend, unfortunately no cameras allowed on site so not much in terms of pics/videos but was a good day nonetheless.

I last visited Hethel in 2016 and to be honest it was a bit of a dump. The factory itself looked like it wasn’t producing much of anything, lots of weeds/overgrown bushes around the track and a few abandoned cars littered the grounds around the circuit. Thanks to the Geely money though they’ve had a pretty drastic transformation, beautiful visitor centre thing, manicured lawns and a few prestige classics dotted around made it feel like a totally different place.

Track was great too, perfect tarmac, nice kerbs etc. I remember not gelling with the track THAT much back in 2016, and you definitely get reminded that it’s a circuit built to test cars, and not to make a driver feel “good” on a regular basis. Lots of flowing sequences that are easy to get wrong, and very hard to know when you’ve got right. Oh, it’s very fast too. They slow you down with a cone-chicane but still exceeded my fastest speed records (according to my dash) by a good 10mph…!

I had a kind offer from a friend to take me some spare wheels down, so for the first time ever I could try tracking a Lotus on a “road tyre” for a bit. I did the first two sessions on my AD08RS and treated them with a bit of respect, but honestly the car felt fine. After 10mins or so they did start making lots of squealing noises under heavy braking and turning (but not locking up) so I didn’t try pushing them further. The car generally felt the same in terms of characteristics, didn’t feel lairy and was fun enough to drive.

That said, I bolted my ZZRs back on for the third session and the car immediately felt a LOT faster. Obviously it’s hard to say on a non-timed event, but if I was the sort of person who would have some sort of GPS device in the car that could log times I could probably say with some confidence that the car was immediately 4.X seconds quicker on the first lap out, eventually becoming 7.5 seconds by the end of the day. But I’m not, so I can only speculate.

My damper settings remained as they did at Blyton and I had no reason to touch them all day.

Just before lunch I realised I wasn’t getting a lambda reading to my dash, here we go again. Quick check with the laptop and sure enough, lambda probe has died. I was happy with my fuelling prior to the lambda failure, so I went ahead without wideband correction for the rest of the day.

This is my third probe to fail now.

First one (supplied and fitted by RRR) lasted 2 months-ish and a couple of trackdays
Second one (in hindsight probably a fake) lasted 1 month and no miles at all
Third one (again supplied by RRR) has lasted me all year and 8 or so trackdays

If the next one survives another 8 trackdays/9months I can probably live with treating them as a consumable, but if this one dies quickly I really need to figure something out. Potential options are to ‘downgrade’ to an LSU4.2 which are considered a bit more robust if not slower to respond, weld something into the manifold to shield the probe a bit (Lotus (or Toyota more likely) did this on some later manifolds). Final option is to run a totally separate wideband controller and add it as an input to the ECU.

Interestingly (or not) later in the afternoon I got a check engine light on the dash, I noticed it at about 7000rpm in fifth gear so I shat my pants expecting the sound of a grenade going off behind me but later analysis in the pits showed me it was just reporting the Lambda failure. This is odd because none of my other failures have registered as a failure in this way, and it’s also odd because the lambda was definitely “constantly dead” because I can see from its output flatlining, but the CEL only flashed up under heavy braking or high-G right hand turns… Investigation to follow.

Day finished without incident, and the convoy set off for the looooooooong slog back home.

Ended up home for 10pm, and straight to bed for a 6am start to go watch the BTCC at Croft. I’m dead :laughing: