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  1. Can anyone on here think of a possible cause of this aberrant behaviour on a 1997 Esprit GT3 with Delco fuel injection, please:

    When the air conditioning is switched off, the car behaves impeccably, and idle is sweet and stable.

    However, when the air conditioning is switched on, the idle speed will rise, inconsistently to somewhere between 1500 and 3000 rpm. Very occasionally this will be accompanied by a 'Check Engine' amber caption which clears within seconds.

    Ordinarily, for an idle speed problem I would be looking at the IACV and for air leaks.

    However, prior to recognising that the problem only occurs when the air con is running, I had already bought a new IACV, and it made no difference.


    Regarding air leaks: when the rubber pipe feeding the IACV is artificially compressed, then the engine can be brought almost to the point of stalling, so that suggests that the IACV is pretty much the only source of intake air.

    So those two facts suggest to me that the idle system is doing what it should, and indeed it does whilst the air con is off.


    The air con is such a simple system that interacts with the ECU by requesting compressor on, in response to which the ECU pulls in the relay that provides power to the compressor clutch, that I can’t see how a problem can occur.

    Interestingly though, once air con is switched off, any attempt to restart it is ignored and only actioned once the ignition is cycled through off.


    So, what can the air con do to affect the idle? My shortlist is:

    EMC/RFI – could the air con clutch generate interference?

    Direct electrical cross feed due to wiring loom problem? Unlikely because car has only done 21,000 miles and in general the loom seems to be in excellent condition.

    Vacuum pipes? How can a loss of vacuum, for example at the dashboard, adversely affect the engine idle on an engine whose only vacuum control is of the wastegate?

    ECU Problem? Could the code somehow be corrupted such that the ECU behaves erratically?

    Bad earth causing loss of reference voltage. But the IACV and throttle pot are both connected directly to the ECU from which they receive their reference, so that seems unlikely.


    Does anyone else have any other theories, please?


  2. Hi Trevor,

    I’ve got a 1997 GT3, which is an early dash model, and is a bit of a garage queen having only done 21,000 miles.

    It’s not for sale, but if you’d like to come and clamber all over it then you’d be very welcome.

    There are two downsides: 1) is that I am in north west Hampshire, and; 2) the car is now SORNed for winter.

    • Like 1
  3. Gentlemen,

    Are you really sure that powder coating suspension components is a good idea?

    The risk is that if a small stone hits and microscopically penetrates the coating, then moisture will creep in.

    The consequence of that is that the corrosion will occur beneath the powder coating, an an insidious way where it can be neither seen nor cured.

    Worse is the fact that the ensuing corrosion will simply creep along and spread under the coating.

    The outcome of this is really quite frightening when an apparently perfect component suddenly fails .

    The alternative approach is to have all the suspension components blasted and then re-plated as per original.

    Yes the plating can be penetrated, but if that happens then the consequent corrosion can be seen and dealt with.

    The cost is quite reasonable and there’s a company in Poole, Dorset who I use who will collect, process and drop off – Dorsetware – but I suggest that it’s best to call them on 01202 677939 because they’ll talk you through the options and usually ‘do a deal’.

    I should add that I have no connection with them other than being a many time customer.


    As an alternative, this is a quote from a Pistonheads discussion this week: "You should try Mercury Electroplaters in Camberley, I kept on popping down there to get the parts for my V12 engine zinc plated, they did a great job and even chrome plated my rusty headlamp surrounds. They matched the Jag OEM zinc finish
    Unit 7H, Bridge Trading Estate, GU15 2QR"



    • Like 1
  4. A further update: I've just received a Four Seasons 33403 for my 1997 GT3, and as expected it fits perfectly.

    I bought mine from Topspeed Automotive ( who from what I can gather are a U.S. based parts distributor with a UK outlet.

    Unfortunately inflation and a weak Pound means that the price delivered to UK is now £36.95.

    The part is here if anyone needs it:

  5. 30 minutes ago, Chillidoggy said:


    My gauges had all new plastic casings fitted by Speedy Cables and have been good as gold for 5 years/15,000 miles now. If you fit them carefully enough and don't overtighten them, then they'll be fine. I can't help but think that what you're proposing is a lot of work!

    You're right there's some work involved. I'm waiting on a quote for the scanning and reverse engineering into a CAD file.

    Alternatively, I keep threatening to learn how to use a CAD package properly, so this might be the ideal opportunity to simply draw the casing shape from scratch.

    There are many of the intricacies of the Caerbont casing that do not seem relevant to our gauges, so they could be omitted, whilst taking the opportunity to slightly thicken the plastic case.

    Then of course I'd have the ideal excuse to buy a 3D printer... 😉


    On reflection, I could also update the mounting to use a finely threaded external collar, rather than the metal bracket.


    • Like 1
  6. 3 minutes ago, Chillidoggy said:

    They are Caerbont gauges, and yes, Speedy Cables did the refurb on them, including new casings. Definitely cheaper than new replacements, but they did take a long time to do.

    In my opinion, the cases probably fail due to over-enthusiastic tightening of the securing screws, and/or knocking them when they’re in situ. They really don’t need to be that tight, but if you change them for another type, the originality has gone.

    Thanks for the confirmation.

    I agree with the issue of originality of the front of the gauges, but am less concerned about the casing since it can't be seen with the gauges in situ. Hence my desire to reverse engineer the shape and then increase the thickness of the casings to add strength.

  7. 5 minutes ago, tomcattom said:

    Are they the caerbont gauges? I gather this is not an uncommon issue with their plastic cases.

    I believe @Chillidoggy may have had his dials refurbished by someone but I can't for the life of me remember who it was or find it in his build thread. Hopefully he'll see this and reply and tell us.


    *EDIT* Sorry managed to skip over the line where you have already found the company that does the repairs. I think I need to go to specsavers!

    Yes, they are the Caerbont instruments, whose co-located sister company, Speedy Cables, can apparently repair them, but there are three disadvantages to this:

    The company's name is a bit of a misnomer in the sense that my and many others' experience with them is that they are anything but speedy.

    Second is that I'm told that they charge upwards of £50 to repair each gauge, and third is the fact that I would still have delicate plastic casings.

  8. 2 minutes ago, jonwat said:

    What about touring scrapyards for car with cars instruments with metal cases that you could cannibalise? :unsure: 

    Funnily enough that was my wife's suggestion - to replace plastic with metal - and I considered it, and also discussed it with an instrument repairer.

    Unfortunately we concluded that the way each of the terminals is brought out of the back of the gauge - using a threaded stud - would mean that there would be a lot of re-work necessary to make insulating pillars for each stud.

    I therefore discounted the idea for the time being.

    At one point I also considered buying cheap Chinese gauges from AliEpress and cannibalising them just for their casings...

    • Like 1
  9. Whilst concluding my conversion to LED lighting on Sunday I got a nasty shock when I removed the instrument binnacle cover and found that all five of my minor gauges are exhibiting some degree of cracking.


    The water temperature and fuel gauges being the worst; having cracks around more than 300 degrees of their circumference.


    All this on a car that has done 20,000 miles hence has spent most of its life away from extremes of temperature.


    The cost of replacement is obscene: £450 for five gauges, and I’m still awaiting ‘Speedy’ Cables’ quote for repair, but it occurred to me that either of these solutions will still leave me with the same weakness to future failure.


    I’m therefore contemplating a modern alternative which is to have a casing 3D scanned as a baseline, then converted into a CAD file which can be modified to thicken the plastic to strengthen where appropriate, before being manufactured using 3D printing.


    The non recurring expense of going for injection moulding rules it out unless there’s a demand for thousands, which I very much doubt, but I wonder what the potential interest might be for modified casings?


    I’m aware that the same gauges are used in the Esprit, early Elise and some TVRs (anything else?) so I can’t imagine that I need to make a batch of more than 10 sets i.e. 50 cases initially.


    Obviously I’d want to amortise my initial outlay in scanning and re-designing, but firstly I’d like to get a feeling for who would be interested, please?


    Hopefully this doesn’t count as illicit marketing… but happy to be corrected.




  10. Just to resurrect and update this thread.

    On my GT3 I have replaced my brake/tail light bulbs with LEDs but found, as others have done, that with the ignition on, as soon as the side lights are switched on, the ABS illuminates its warning light. (It’s a ‘97 GT3 so has the Delco ABS system)

    I concur that this is because of the inner workings of the LED ‘dual’ bulb which is, in fact, only one, and that it effectively back feeds the ABS Controller through the bulb sense wire.

    My instinct was to overcome this by simply adding diode in the feed to each brake light, such that power from the side light circuit could not get back to the ABS Controller. Unfortunately the forward voltage drop across the diode seems to be too much for the ABS controller which continued to show a warning.

    In order to persuade the ABS Controller that there is a good circuit path to ground I have therefore also added a 4k7 resistor between the anode of the diode and the bulb’s earth wire.

    This seems to do the trick.

    • Like 1
  11. I am in the process of possibly the slowest Esprit rebuild in history, but the end is in sight, and I’m chasing fiddly odds and ends.

    With that in mind, does anyone please know, or happen to have a photograph of the fixings that are used on the rear radius arms (trailing arms) to locate the handbrake cable, the speed sensor cables and the rigid brake pipe.

    From memory there were a mixture of plastic and metal clips, but I can’t find them in the remaining parts tubs, nor in the parts catalogue, they’re not listed on SJ Sportscars’ web-site, and Googling hasn’t yielded a picture of an assembled trailing arm.

    As the Classic Car Show is on at the NEC next weekend I thought I’d have a trawl around the inevitable flea market, but only if I know what I’m looking for.

    Many thanks in advance.

  12. Yes, it interested me too, so I enquired about its status and this is the reply I received:


    "Hi no mot or tax not sure about service history I have had car about 8 months got it from a job I was on. It has been some one pride and joy as you can tell from condition but only got log book. Thanks."


    That rather calls into question the "one owner from new" statement.


    Judging by the underbonnet photos I think it has been stored somewhere none too dry.


    I suspect it might need a bit of tlc to get into roadworthy condition - certainly to the point where it's fit to be used daily.

  13. Paul,

    You may not have seen my reply to your question on Pistonheads, but if you google "retroviseur cx electrique" you'll see that there are a few second hand mirrors on le Ebay and also a company called Auto Prestige is offering a pair of brand new manual mirrors for €100. It can't be too difficult to transfer the positioning mechanism across, can it?


  14. Last summer after a trip to a very wet CarFest I suffered a very unusual problem: whenever I drove the car there were streaks of what looked like white emulsion down the left side of the car – investigation revealed that they appeared to originate from the near side lamp pod.


    Further investigation revealed what look like tiny bits of papier-mâché strewn inside the luggage compartment. One of which was big enough to read and that’s when we figured out what had happened:


    My car lives in the garage with its nose pointing towards the doors, in one of which is the letter box, and it seems that an errant envelope had, when pushed through the letter box, not dropped, but instead flown a couple of feet or so and dropped at just the right angle to fall unnoticed down the back of the pod. (You couldn't repeat it if you tried...)


    Then, after two days in the rain the envelope had disintegrated sufficiently to block the drains and had gradually dissolved into a white paste to be distributed by the air flow. Lovely…


    You don’t mention what the change by 4 units is equivalent to in percentage terms (or should that be in perhexage?), but if the closed to wide open scale is nominally 28 to 255 then that represents an unacceptably large drift.


    I’ve previously used the standard “rotary position sensor” that RS sell for about £25 and that is more stable than you’re


    Have you considered that the throttle pot may be the victim and not the cause, and measured the Vref that it receives,
    and the pot’s Vout to see whether they vary similarly? (Sorry if teaching you to suck eggs…..)


    If you’re adamant that it is the pot that’s at fault then the next step is to use a Penny & Giles TPS280DP which is a
    contactless device that contains some pretty trick electronics which is claimed to have a stability of ±30ppm/°C. From memory the cost is somewhere around £120.


    So far I haven’t used a P&G myself but I’m currently in the process of fitting an injection system to a 1972 Porsche 911
    for a friend and the P&G device is what we’ve settled on….

    ... and apparently P&G deal with the great unwashed directly without having dealers as such.




  16. Given that the transmission cases are made of aluminium alloy, I'm surprised that no-one has suggested placing a support under the driveshaft whilst punching out the pins. I used a block of wood with a vee cut into it, supported by a trolley jack.


    I also went and bought a couple of brand new pin punches for the occasion, which, when assisted by a 4lb club hammer were extremely effective in shifting the pins first tap!

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