Over the years, many questions have been asked. These are some of the answers. If your question isn't answered, please send it via the Contact Form and we'll answer it here.

1. "The headlamps are rubbish, more like candles than headlamps. What can I do?"

A: Experience tells us that most headlight problems are caused by corroded reflectors (or even just dirty lenses). Look at yours carefully, if they're full of water or looking a bit brown at the bottom, then you need to think about replacing them. Unfortunately the original "push-fit" 7-inch units (shared with the original Mini) are no longer available, but a little careful modification to the headlamp pods allows any 7" unit to be fitted. Some people favour Wipac Crystal units, where the mirror does the focussing, while others have gone for LED.

If you think your reflectors are OK, then please try an upgraded lamp, like the Osram Nightbreaker, as a cheap starting point. H4 is the correct fitment. You should also check the connector for corrosion as this has been known to cause problems too. Replacement connectors are readily available and not very expensive.

2. The brakes are rubbish. What can I do?


  • Firstly, the braking system is a 1970s design. It's adequate for what it was designed to do, but not for modern driving styles which involve stamping on the brakes at the last minute. That said, the calipers are known to corrode a little and prevent the brake pads moving freely, so the first thing to check is that the pads can move freely.
  • Secondly, the non-return valve in the brake servo sometimes fails. They're easily replaced and a fairly standard part.
  • Finally, if you still don't like the classic braking feel, big brake kits are available from LotusBits and PNM engineering amongst others. They take about a day to fit.

4. My carburettors have a lot of extra hoses attached to them. What do they do? OR

I'm having problems with idling and carb. balancing - could these extra pipes be the problem?

A: Over the years, Lotus added a lot of extra vacuum pipework as part of an attempt to control emissions.

It's common for perished hoses or failing "vacuum switches" to lead to problems.

The "vacuum switches" are still available as Jeep parts, but a check of the condition and location of all hoses is a good starting point for curing many idling and fuelling problems.

Bryan Barker produced this helpful diagram, of the final arrangement, which shows all the hoses in their original factory colours. Colour is not important, but the end points are. (Earlier cars don't have the carb. "F" pipes, and LC engines don't have the vac. advance on the distributor.)

5. My car won't start, but the battery is fine, what's the matter? - and other electrical issues

Depending on the age of your car the most likely sources of electrical faults are corroded connectors, water in relays and fractures in the wires themselves. Start by checking the relevant connectors carefully and cleaning them up. If they're OK, get the wiring diagram for the year of your car (there are 4 different looms, depending on year - ask nicely through the contact form and we might be able to help) and look for fuses and relays which affect the failed circuit.

For starting problems - if you can't hear the starter solenoid clicking, then the prime suspect is the start drop-out relay which cuts power to all non-essential circuits while the key is in the start position. If the solenoid is clicking, but the starter isn't turning - then you may need a new starter. Replacing the starter is a pretty easy job and can be done in 20 minutes once you've had some practice. Of course, before you swap the starter, you should check that all electrical connections between it and the battery & alternator are good and free from corrosion.

As development of the Excel progressed, more relays were added, and they were grouped together in just a few places around the car. The cluster in the driver's footwell (UK) is particularly prone to accumulating water if your car leaks at all. This results in corrosion inside the relay which eventually breaks the circuit. Most regular drivers carry a couple of spares and know which ones can be swapped around to get the car moving again. Ultimately, though, the best cure for corroding relays is to fix the water leaks...and then replace the relays - and still carry a spare or two, just in case.

6. Do I need an additive or new head to run on unleaded?

No. The Lotus 9xx series engines were designed for unleaded from day 1. They benefit from higher octane (super unleaded) but can run on standard 95 RON (UK) fuel if you retard the ignition timing a little.

3. My ignition amplifier has failed, or I'm getting misfires and idling problems, what can I do?

A: The AB14 ignition amplifier is actually pretty reliable. Over the years we've tested a number of "failed" amps. and found that they were all actually working correctly. Before blaming the AB14, there are a few checks to carry out:

  • First - check the condition of the wiring from AB14 to coil, particularly the wire ends at the spade connectors. After a few decades of exposure to heat and vibration, you may find that many of the strands have broken, resulting in poor performance. Strip them back and fit new spade connectors and your problems may go away. Also check for corrosion on the AB14 terminals and clean them up if necessary.
  • Second - try disconnecting the rev. limiter. It sits lower down on the wing, ahead of the AB14 and is a known weak spot. When it starts to fail it can cause non-starting, misfire, poor idling and lack of acceleration. Pulling the plug from it often cures "AB14 problems". It's possible to fit a replacement modern rev. limiter if yours has failed.
  • Third - the "black wire" from distributor to AB14 also fails due to flexing, heat and vibration. If waggling it allows your car to run normally for a while, but then return to previous bad behaviours, it's probably time to replace it.
  • Fourth - if all else fails, follow the Lucas diagnostic procedure to figure out which part of the ignition system is misbehaving.

If your AB14 has failed, then a replacement DAB125 (or Intermotor 15210) ignition module is likely to bring it back to life, as long as you get a real one from a reputable supplier.

7. All Lotus leak - do I need a garage and is it safe to leave an Excel outdoors?

Actually, not all Lotus leak and they were certainly not intended to leak when they were built. If you are getting water inside your Excel then your car has developed a leak which needs to be fixed. See this page for more info.

As long as your car isn't leaking water, it can live outside without too many problems - as long as you use it regularly. Of course, keeping it in a garage or under a good quality cover will help to preserve it - as long as you use it regularly to keep things freed up.

Where can I find an alternative part for ....?

Firstly - not everything on a Lotus is sourced from another manufacturer. However, our sister site, www.LotusPIG.org.uk is building a list of alternative parts which might have the answer to this question.