Jonathan Kay

Sometimes there's one or more tiny grub screws: /forum/chitchat/gear-knob-1 /forum/techtalk/stupid-question-refitting-gear-knob Jonathan

"so you are saying that as a security issue (prevention from unfastening in case someone might use the wrong nuts) one shorter stud was used on purpose?" No. I have no idea why yours are like that. But if the nuts are closed-ended then I'd check what's happening when they're tight. The stud mustn't bottom out in the nut. Jonathan

No idea why yours are like that. But there is an issue on Sevens where if you use closed-ended nuts on the wrong length studs the attachment can be insecure. Jonathan

"I will check the drop of voltage when cranking of the old battery (voltage at rest is 12.65V, so approx 80% capacity up to my knowledge). What´s the value it should not drop under when cranking? 10V ?" Probably something like 10.5 V. Some electronics might drop out below that. The strange thing is that it might still be able to crank at a decent rate. I recommend measuring this routinely in the same way that we check oil levels. It's probably the easiest way of detecting deterioration as early as possible. Jonathan

Thanks Jonathan

Intermittent and lots of possible causes... Has this happened when the immobiliser hasn't been set recently? And is that the factory immobiliser... two buttons and a battery in the fob? Any recent work? I'd start (!) by: 1 Measuring the battery voltage at rest, minimum during cranking, and idle. 2 Checking all of the relevant wires: battery, starter, ECU, ignition switch, starter button and relevant earths. Inspect, wiggle, disconnect, clean, reconnect. 3 Having a look at that starter button. Is it really a button rather than a position of the ignition switch? When was it fitted? Would you like a copy of the appropriate wiring diagram? Jonathan

Well done. Jonathan

The treatment of old cars has been pretty generous in the past. I don't expect that to change. I'd guess that the use that's most at risk is driving them in low emission zones. Jonathan

IIRC there are several battery-only 7ish cars in the 7 Concept Car thread. Including a video. And there's one in the background on Vintage Voltage. But the simple swap versions are going to be just what you'd expect: fast, quiet and heavy. Jonathan

Yes. Have a look at this thread and please add your experiences and thoughts to it. Thanks Jonathan

"When you don't hear the fuel pump does the engine crank normally? --> yes, but it does not start Does it always start eventually? --> no. The last few times I just waited until next day while as a precaution charged the battery. Next day all was good; engine started directly." Good advice above. 1 Have a good look at that inertia switch and the wiring connections. Inspect, wiggle, disconnect, clean, reconnect. 2 Have that little jump wire available in the car so that you can try shorting out the inertia switch the next time it happens. 3 Identify the fuse for the fuel pump. Check that it is gripped nicely. Remove, clean, and put it back in. 4 If it's the type of battery that needs topping up then check the levels. 5 Measure the battery voltage at rest, the minimum seen during cranking, and at 3,000 rpm. Tell us what they are. Cranking is the most convenient DIY load test and will tell you about the condition of the battery before it fails. Or that the battery isn't the problem and that you don't need to replace it blind. Jonathan

Identifying cables: You have the wiring diagram. It can save time when identifying cables by looking them up in the "standard" British wiring colours, eg: https://www.autoelectricsupplies.co.uk/cms/files/colour_code_for_vehicle_wiring_-_new_order_2.pdf Caterham usually adhered to these. Eg that Brown is very likely to be a "Main battery feed". Jonathan

Thanks Jonathan

"So it directly affects the fuel pump, right? Because I sometimes experience that the fuel pump does not work when starting (the immobilizer has been correctly turned off though). And I am thinking if this switch might have anything to do with that? (malfunctioning somehow?)" *It does. But it's going to be hard to find out what's happening: intermittent failure and lots of possible causes. When you don't hear the fuel pump does the engine crank normally? Does it always start eventually? Have you got a multimeter? Jonathan * Unlike the immobiliser!

Please let me know if you would like an Assembly Guide and Handbook. Jonathan

Very good. We had some constructive exchanges with them, although I think that there isn't a current special offer to Members. I have some wiring diagrams and manuals if anyone needs them. Jonathan

How many relays are there, including that one? And are they in one row or two? Thanks Jonathan

Yes, but which position is it in amongst its fellows? Jonathan

Please could you let me know if it isn't in the position shown in the Handbook. There are at lest three layouts on Sigma-engined car... Jonathan

"Somehow the wording on my actual post didn't appear after posting on my phone. Is that a known forum problem." Android? There's a known problem. Jonathan

Let me know if you need an Assembly Guide. And here's Shaun's bolt list for both Imperial and metric chassis. Jonathan

The layout should be in the Handbook. Let us know if you can't find it. Jonathan

Some part numbers and nominal power. Jonathan

I think that it would be difficult by feel. How about a smart 'phone pointing at the back while you look at the screen? Or used to take a photo? (But the gauges are easy to release.) Jonathan

I listed the factory bulbs once, but it was in a discussion of decreasing the power by migrating to LEDs! I'll try and find it. Jonathan