2006 Exige S

This is where we proud owners can upload information and pictures of our pride-and-joys (their Exige that is..)
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Fonzey
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Joined: Tue Nov 27, 2018 12:17 am

andyzim wrote: Fri Jul 23, 2021 8:58 pm I can't wait to book a day at Donington in the Exige, it's my favourite UK circuit.
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.

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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 :( It wouldn't rev above 3k, was heavily missing and sounded really lumpy at idle when we brought it back in.

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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.

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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.
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Fonzey
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Joined: Tue Nov 27, 2018 12:17 am

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 :(

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?!
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andybond
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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.
seriouslylotus
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Check fuel pressure. Open flow is almost irrelevant,
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Fonzey
Posts: 1339
Joined: Tue Nov 27, 2018 12:17 am

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.
seriouslylotus wrote: Thu Jul 29, 2021 7:54 am Check fuel pressure. Open flow is almost irrelevant,
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:
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Fonzey
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Joined: Tue Nov 27, 2018 12:17 am

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'.

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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.

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

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.
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Type116
Posts: 77
Joined: Fri May 01, 2020 3:18 pm

what are your plugs gapped to?
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Fonzey
Posts: 1339
Joined: Tue Nov 27, 2018 12:17 am

Type116 wrote: Fri Jul 30, 2021 7:19 am 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.
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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.

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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.
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Fonzey
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Joined: Tue Nov 27, 2018 12:17 am

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.

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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.

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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:

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(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 :lol:

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:
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thommo
Posts: 4913
Joined: Tue Jul 13, 2004 12:50 pm
Location: Lancs

Great news! You’ll be down at Caffeine & Machine, then ?
Exige S1 No: 139
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