Lucas 14cux Fault code reader

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Richard Coupe

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8
Hi, anyone know where I can get one of these? Got a '95 LSE 4.2 that refuses to start except for the odd brief moment, then stops with check engine light lit. Checking through we have determined that the fuel pump relay is not being enabled by the ECU in fault condition, but other electrics are ok. Stuck for where to look next but I have read that a plug in fault code reader exists which may tell us what the ECU thinks is wrong!
 
For how useful it is going to be,compared to how much it is going to cost I wouldnt bother.14cux is a fairly simple system and with the correct electrical troubleshooting manual from Lr you should be able to sort it out.I have testbook T4 but rarely use it on these cars,my multimeter is usually the biggest help.Dont panic about coolant temp and air flow meter sensors - these can all be disconnected and the engine will still start.It wont run very well, but it will go.So as your car wont start, let alone run,you need to go to basic things like fuel delivery/pressure and sparks happening at the right time etc.From memory I think the engine needs to get to 550rpm before the cux strarts to look for sensor inputs.Having a known good vehicle alongside to take readings from or borrow bits from can be a big help,and dont worry about coded ecu's etc,14 cux can easily cope with bits being swopped - just turn off the ignition and get on with it.Good luck !
 
Thanks for that. Its desperation that has driven us to ask for a fault code reader! I have a RAVE manual on CD care of ebay and have gone through some of the electrical checks with my multimeter and found nothing wrong with voltages. What I managed to find was that we got sparks but no fuel pressure so I checked the fuel pump relay & it was not energised. I tested the relay, fine, ECU wasnt sinking current to turn the relay on. But occasionally everything is fine & she starts a treat, smooth running for maybe 10 seconds to a few minutes then cuts out, check engine lit. The ECU is shutting the relay down for some reason & this is what I'm trying to determine. We have checked connections carefully, buzzed lines for good continuity etc, but cant find a problem. When we first got the car (3 weeks ago) all seemed well starting although the car was only driven a short distance once. It was left for a week and started OK and turned off but then battery was low/flat (just a click on starter motor, not turning over) so we jump started it (the RAVE manual states jump starting is OK) and it aint been right since.
 
Does the fuel pump run for 2-3 secs when you first turn on the ignition ? It should do this to pressurise the fuel rail ready to start the engine.The fuel pump relay will not then run again till the ecu see's a signal through a 6.8k resistor from the -ve side of the ignition coil.Check this out from the coil right up to the ecu.If this is all ok,then I would try another ecu - it does not matter if it is off a 3.9 or a 4.2 just for the purposes of testing.Where are you located ?
 
Sometimes fuel pump runs briefly & starting is ok but this is intermittent, so we spotted that something was wrong here, no fuel pressure. I will check the 6k8 resistor this morning with my meter, this is something we havent looked at yet. I dont have another ECU to hand to swap out unfortunately. I am located in Billingshurst (A29/A272 crosses here), West Sussex. Thanks for your help!
 
It might be a good idea to hook up a 12v bulb to the fuel pump feed, right back at the pump - then you will know exactly when it is or isnt being powered.I'm over in the west country - bit far away to swap ecu's,but I reckon you will find a wiring fault,cux ecu's are very reliable - not like the old 3.5 lucas 4cu ones,I would have suggested subbing that before doing anything else ! Good luck with the wiring checks - I think you are close to finding it now.
 
If you are still having trouble find an independant repairer with one of the testbooks or a Rovercom and get them to do a fault reading for you. They may well be able to tell you why its giving trouble and how to fix it.
 
I looked for the resistor & found 2 taped to the side of the loom sheath up by the coil. I measured resistance of both, one was 6.9k the other 7K, near enough I guess. Both resistors had same wire colours, white/black in, white/blue out but one had a red ring around the white/blue. I measured the voltage on the resistor terminals, got battery voltage (12.9V) on white/black on both but about 12.8V on one and 10V on the one with red ring. The connectors were a bit corroded so I wiggled them about and got good continuity, hey presto - she started instantly and ran for a couple of minutes, smooth , regular - beautiful. I then made the mistake of thinking I had found the problem, while telling my friend I had done it the thing cut out again, same old check engine light! So after a cuppa, I went back & rechecked the coil voltages. Section 86 Electrical section on the RAVE CD describes fault diagnosis - I did test 2 & got the expected readings, then test 3 but got an error with voltage from battery +ve to coil -ve, I got a reading of battery voltage not 0V, with ignition OFF so the amp or the ignition resistor is pulling this line down. With ignition on the voltmeter reads 0.08V and the manual reckons 0V (so thats probably right). So something is odd here, seems to point to amplifier but what bothers me is the intermittent nature of the problem - the amp is fixed tightly to the body & wires look good. I would love to know whats inside this amplifer! This Rangie is owned by my father-in-law who lives in North Devon, near Torrington, how close is that? I will hunt around for an ignition amp now. Thanks for the light bulb suggestion, when time allows I may try this if the amp swap isnt the answer.
 
Hello Goneoffroad, thanks for that advice. We have called the local dealer to see if they offer a callout service but dont, only option was to get the car transported to their garage and have them fix it. We decided to have a poke around first incase its something simple (dont laugh please) and so save the expense. If there is someone who would come to West Chiltington (West sussex) with a fault code reader we would be most interested in talking to them, please get in touch!
 
Dont give up ! Sounds like you are very close to finding the fault.Poor connections in the low tension side of the ignition system can be very frustrating to find - even for a pro.
I still maintain that testbook is going to be no help - 14cux fault codes are very basic and mostly relate to poor running issues,not poor or non start issues.Its not till you get to 1999 on bosch motronic injected RR's that you would get any light shed on a non start car.So dont waste your money - I think you are 95% there.Another idea that may help is to draw out a large scale diagram of the ignition system,laid out the way the car is and mark everthing on it - including the cable colours and expected meter readings etc.
Also leave a timing light connected to the coil lead so you can monitor sparks while the engine is cranking/running.
Go for it !!!!
 
Hi 8inaV, no giving up here! I'm not letting a moody ignition system get the better of me! I was looking at ebay for a 14cux & one came up but I was too late, went for £50, it would have been worth having just to plug in & try, maybe keep for the future. We hear that the ignition amps can go down sooner or later so have ordered one from local dealer to try - if it isnt this at least we got a spare for later. If its not this it could be the HT coil or the pickup coil from the distributor (spares on ebay for these), nothing else connected to this part of circuit to check. It would be nice to get a manual just for the ECU system, I'm curious about this gadget & would like to know its inputs/outputs & how it copes with failures or out of tolerance conditions (this more technical stuff seems hard to come by), I may be able to repair one with a circuit diagram to follow, if the controller chips perpherals are damaged - an electronic circuit like this must be pretty well protected against its environment. I will ask around for a timing light & try again when amp arrives & get back to you. Thanks again!
 
Way to go ! The info on the rave cd is about as far as has been published,to go any farther only recognised experts will have more - probably what they have worked out for themselves.Having spare units is a good way to troubleshoot once you have gone beyond basic electrical checks.Make sure the bits you buy are all in good working order - fitting them on a known good car is this best test,and mark them as ok before you store them in a nice dry place for future use.Keep going !
 
It would be nice to get a manual just for the ECU system, I'm curious about this gadget & would like to know its inputs/outputs & how it copes with failures or out of tolerance conditions (this more technical stuff seems hard to come by), I may be able to repair one with a circuit diagram to follow

The info on the rave cd is about as far as has been published,to go any farther only recognised experts will have more - probably what they have worked out for themselves

I agree, you won't find any info on the workings of the ECU - Land Rovers anwser is to replace rather than repair - typical of how things are now-a-days*

There are a couple of companies who will repair an ECU for you if you send it off to them, but like eight said, I think they get their knowledge from working things out for themselves.
http://www.carclinicmagazine.com/ecu_exchange___repair.html

*My grandfather dunked his video camera into the river a while back, the insurance company wrote it off (it was worth £2500!) and paid out. He asked if he could keep the camera and they agreed - he took it to a specialist and they fixed it for him for £350!
 
Well I thought an update was in order. I swapped the ignition amplifier & still get check engine light. If ignition is turned off and back on, still get check engine lit. When check engine is lit, fuel pump doesnt run but we get ignition sparks. Occasionally when turning ignition on, check engine doesnt light & she fires up and runs well, sometime engine runs for a couple of minutes then cuts out with check engine lit. Next thought is to substitute another ECU but need to acquire one, possibly from ebay. I havent given up yet!
 
you cant beat the 8 track have you all seen them new tape player thing for cars might get one
 
Funny you should say that Yella - he's seriously into film making and video editing - the room where he has it all in looks like bloody Nasa! - but asking him to set his domestic video to record a program and he hasn't got a clue! lol

You back on the road yet dude?

Matt.
 
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