1993 3.5 V8 discovery running problems

Basically I'm new to the whole V8 scene. One morning my disco cut out and wouldn't start again. It smells like its over fuelling and when I pulled the plugs out they were black an wet which is a sign to me of overfuelling. I am wondering where to go with it? Common faults? I have heard about this ninth injector or something so could anyone enlighten me? Where is it located and would it be a possible cause? It now runs but is very gutless and stinks of fuel. It also sounds like its misfiring. It's had new ht leads plugs, dizzy cap and rotor arm and fuel filter aswell.

Thanks guys

Joe

Is this when the engine is hot or cold? did the engine restart after you cleaned the plugs?
It could be as as simple as a faulty engine coolent temp sensor informing the ECU that the engine is cold although it is hot or more serious it could be a faulty ECU.
I assume the engine is in a good service order and ignition system is ok fited with genuine parts and air filter is clean.

The ninth injector is what my 1987 3.5 had it was screwed in to the left side of the plenum chamber and operates injecting neat fuel into the plenum on cold starting which IIRC was somewhere around -20c so something not used much in the UK, you may or maynot have this injector on your year of engine.

yes he shouldnt have it as it should be running hotwire injection 14cux

did the problems only arise after the new service parts were fitted? were they genuine landrover parts in landrover boxes?

No it seemed as though it was misfiring and over fuelling as soon as I had it. I was running it for a couple of days, started fine in the morning and cut out. Didn't wanna start again. Plugs were wet and black. They were genuine parts yeh. And yes the engine runs now, but it's really gutless, stinks of petrol fumes and misfires. Where is the coolant temp
Sensor located? Is there 2? One for the ecu one for the clocks?

yes there is, they are on the or about the stat housing, inlet manifold area. its the plastic topped ling thin one you want for the ecu, make sure you replace it with a genuine landrover one. LR direct do them if you ring them and ask for paul he can sort you out.

you can test the voltages in haynes manual but its not fool proof.

so it was running well at some point in your ownership? if its from a trader I would take it back and get them to sort it.

getting th fault codes read would help. you can buy the machine to do it yourself for £100 and it will come in handy for you entire ownership

There is no engine management light on at all. And is the wire a thin green one?

Joe, a 93 engine will not have the ninth injector, as Fett said should be hotwire with 14CUX ECU.

I would suggest taking out the plugs and disconnect the ECU, spin the engine over to clear the bores. Dry and replace plugs. Reconnect ECU. Slacken dizzy clamp then get an assistant to crank the engine as you advance the timing.

BTW I assume you have checked you are getting sparks?

If you can get the engine running it might be worth checking O2 sensors (if fitted). If duff sensors indicated I have two you can have but I don't know if they are good or not as I took them out of a stainless exhaust I picked up for my RRC which doesn't have cats.

Yeh I have checked for a spark, nice spark on all plugs. But one thing I did notice. When the engine was running I removed one ht lead at a time
To listen to the engine note change. When I did this on the N/S bank no change in the engine pitch could be heard. Would it run on 4?

Joe Edwards said:

Yeh I have checked for a spark, nice spark on all plugs. But one thing I did notice. When the engine was running I removed one ht lead at a time
To listen to the engine note change. When I did this on the N/S bank no change in the engine pitch could be heard. Would it run on 4?

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Yes it will run on 4 but would be really rough and uneven. Rough running could be so many things, if you can at least get it to run you know the fundamentals are working - Fuel, Air and Sparks.

Now you need to understand if you have an ignition misfire or an injection misfire. This can take a long time so patience is required. Check/test as much as you can with a multimeter. If you suspect your ECU let me know, I have a spare one you could plug in to do a substitution test if necessary, you're not far from me so could be doable.

FWIW check/test your air flow meter - do a search, quite a few posts about what/how to do this.

also a noid light on ebay for £7 will tell you if the injectors are working.

dont be put of this is normal landyness, after you have got this sorted in a few weeks you will also be able to fix most stuff that could go wrong with the engine quite easily. 14 cux is quite a nice easy system to work on. most mechanics tend to not know fook all about it though. I would get that fault code reader

14CUX ECU fault code reader TVR Range Rover Land V8 | eBay


as thay have got even cheaper since I had mine and it can elimate a lot quickly. the only time I have ever heard the efi light come on was when there was a bloke on here driving about with no alternator belt on and asking us why hes battery was flat. anyway point is really that efi light doesnt really tell you much and every fault I had with mine never cause it to come on.

we are here if you get stuck

Yeah it's running but really badly and there is hardly any power at all. And like I said there was no difference in engine note when I took the leads off the n/s bank. I think someone is looking at it thursday. A local guy who knows them inside out so I will eat some humble pie and send it to someone else. If no luck, I will re think a plan

Hi Fett,

Dunno about EFI warning light never coming on - mine is right twitchy sometimes, comes on for no good reason, give it a reset and all is well. Guess I don't need to tell you about the gremlins though!

Joe Edwards said:

Yeah it's running but really badly and there is hardly any power at all. And like I said there was no difference in engine note when I took the leads off the n/s bank. I think someone is looking at it thursday. A local guy who knows them inside out so I will eat some humble pie and send it to someone else. If no luck, I will re think a plan

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Fair enough but don't loose your shirt! Keep a note of what you have tested and the parts you swap out. Be aware that ignition parts need to be genuine, especially rotor arm and dizzy cap.

If the temperature thermistor is suspect try bridging it and see if that makes a difference. Check the throttle pot for initial voltage and then check it for scaling - the throttle pot should move smoothly with no notchiness and output voltage should also scale smoothly.

Another thing to check might be to fire the engine up then disconnect the air flow meter, if the engine smooths out air flow meter is suspect. I have a spare if you want to try a substitution.

How many miles has the engine done? What is the ignition timing set to and does it have LPG?

I know - lots of questions, but finding the cause for rough running/misfire is a sometimes long process - stick with it. Like Fett said, once you've been through it and the engine runs sweet you'll soon forget the frustrations.

Thanks guys. I have a few things to keep me
Busy checking now. I have tried the air flow
Meter disconnected and it really wants to cut out.

Joe Edwards said:

I have tried the air flow
Meter disconnected and it really wants to cut out.

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Give it some revs then see if it will idle. With AFM disconnected the ECU should swap to the limp home map - this basically just chucks fuel in the engine so it will run. Don't drive it like this too much though (been there done that) coz you'll be getting something like 6MPG irrespective of how you drive it!! When I did that it turned out the air flow meter was fine but the ECU wasn't reading it. Swapped ECU, never looked back.

BTW if you do that don't forget to disconnect ECU and then plug it back in again (resets ECU) when you reconnect the AFM or it will stay on the limp home map.

I wonder if your dizzy has moved on its own like mr noisys did (I think it was him).

Although it does sound more like its overfueling, the lack of power would make me think timing.

I hope your bloke knows the 14 cux well , as I had several so called experts cost me an arm and a leg and acheive fook all. once I had the fault code reader it just makes it all so easy- not that its foolproof of course but its bloody good and saves hours of mulitmetering and swapping bits if you get a hit straight away for the price of mosta garages hours labour. I dont sell them btw lol

Anothe rpoint kev touched on is does this car have cats fitted? as the lambdas open up another avenue for your type of problems.

fett said:

I wonder if your dizzy has moved on its own like mr noisys did (I think it was him).

Although it does sound more like its overfueling, the lack of power would make me think timing.

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A strong contender for sure. Dizzy can move if not clamped tight but also had a timing problem with mine a few years ago - timing was wandering all over the place, turned out timing chain was stretched.

yeah I think mine was going that way, I could only get it to tick over at 500 rpm with the timing right and base idle set properly. It ran that way ok for a couple of years but I didnt like it lol