Chazza

Thank you.

Thank you for your suggestion. It idles on all 8 cylinders but I will check with a thermometer to see how hot the exhaust manifold gets. Can you suggest where I can buy a plug to go on the injector? I can make a test-lead, Cheers Charlie

Good idea, thank you.

Yes.

Hello everyone, My Disco 1 has been stuck in the shed since May last year with a misfiring problem on No.3 cylinder. I rebuilt the engine 3 years ago, properly, and it was running superbly when it was last driven and then not running the next morning. The car has done 320 000km and is in good condition. A compression test showed every cylinder on the same pressure at about 170psi cold; which indicates to me that the valves are working properly. No.3 spark plug is always clean (no soot) and fuel is obviously rich at the exhaust outlet and is exploding in the system. The other 7 plugs are dry and sooty. So a list of parts changed; New spark plugs. New distributor cap. New coil – the right type. Ohms test on all high-tension leads; the figures made sense. New airflow meter. All injectors sent away for a clean and check. New injector on No.3 New fuel temp sensor. We have tested the ohms on the harness to the injectors and No.3 was different to the rest, so my brother soldered all of the harness joints, on both sides of the engine. Can anybody think of something I have missed? It has been quite maddening to have the car off the road for so long, Cheers Charlie

Well not quite; it was idling well but bangs and pops when a gear is engaged! Aaaargh! Seems as if No. 3 is over-fueling again. Despite having the injectors serviced, it appears to be time to substitute it with another one.

Well some good news and hopefully an end to the questions. My brother explored the injector harness in the valley and found the join for all four injectors. One of the wires to No.3 showed a random ohms reading. The joint was crimped not soldered, so he soldered it for me and then went and did the other side. Running on all 8 cylinders now! So if anyone else has a similar problem, unwrap the harness under the plenum chamber and the harness on the right-hand side to find the two joins, Cheers Charlie

Hmmm! There was chap on here from a Pacific island, who discovered that his air-conditioner wouldn't work when he converted to MS. Surely the alarm ECU must disable the ignition system somehow? Perhaps not. Thank you for your thoughts.

Discovery 1 V8, 3.9litre. Automatic transmission; air-conditioning; alarm ECU; central locking; air-bags. You may recall that in another thread I had trouble with one cylinder miss-firing. After exhaustive testing and substituting I am convinced that the No. 3 injector is getting a signal to squirt but not one to shut. So I have decided to install the MS2 which has been sitting in the cupboard for years. So I ask you this question first; Can the Rover ECU be left in place? I suppose that it controls, or communicates with the Alarm ECU and perhaps the other things in the title at the head of this page. Will removing it make the car un-functional? Can the MS2 do the injectors and spark with the old ECU still there? Cheers Charlie

I don't disbelieve you but I would rather put the effort into converting to MS. Hence my desire to getting it running well again, first of all, Cheers Charlie

Ah ha! Missed that in your earlier question. Thank you that will be worth changing as the car is rather old, Cheers Charlie

No I haven't. See my reply to Fridge. Thank you for the advice, Cheers Charlie

Yes, I changed the sensor on the fuel rail. My hunt for bad earths will continue – under the dashboard I guess? Where can the ECU be found? I think the richness may have been because the engine was cold. I plan to run it today and get it hot, it isn't road driveable. Thank you for your suggestions, Cheers Charlie

Well still no luck. The fuel temp sensor has been changed and a new MAF meter installed - no change. The car did have a bad earth somewhere on the body, because the new battery couldn't crank it. I installed a new earth cable between the body and the chassis and that has fixed the cranking problem. Which means there must be a bad factory earth somewhere on the body. Could a bad earth be affecting the ECU somehow? My next suspect is petrol quality; I bought half a tankful from another town and the problems started the next morning. Might have to siphon it out; trouble is I don't have enough containers for +50 litres. Can anyone think of anything that I haven't tried? Dodgy ECU or signal to it perhaps? I want to install the MS but I would rather have the thing running properly first. Going back to my first post; what happens when the fuel regulator plays-up? Cheers Charlie

Thank you for your thoughts everyone. Yes, no oxygen sensor or cat. converter on the car. I have ordered a new coolant temp. sensor as it was fairly cheap. Although I have a good understanding of basic circuits and how to make and test them, I am lost-in-the-woods when it comes to testing components. Thank you for the ohms scale Fridge, Cheers Charlie

Single coil of the right type. May well be a coolant sensor; any thoughts on how to test it? Could be an MAF as well; if so it will be time to finally install the MS.

Still trying to track-down the cause of a poorly running engine. Can someone please tell me what the symptoms are for a fuel regulator failure, on a V8 serpentine belt please? My engine starts and idles slightly roughly and gets worse as it warms-up. There are explosions somewhere in the exhaust. Cold compression-test on this rebuilt engine is 170 psi on all 8 cylinders. I have changed the spark plugs, coil, distributor cap and no. 3 lead with no change. Discovered a very wet and clean no. 3 plug, so I had the injectors serviced - no change. So the engine is definitely running rich. The symptom appeared suddenly overnight, after running superbly on a 400km drive. Cheers Charlie

Thank you Fridge that is very helpful. What is a flapper? Cheers Charlie

Hello everyone, I think I have a dribbly injector and after 310 000km it might be time for new ones. Can someone tell me please what make and type the original injectors are? Cheers Charlie

Magnecore are superb leads and they don't seem to wear out. In my experience the extra price is quickly negated by the need to keep replacing cheaper leads, which barely last three service intervals. The magenecores on my Disco have now been there for more than 100 00km. Use Iridium spark plugs as well for the best possible spark. You ask how important the leads are! Just as important as every other component on a petrol engine. You do want the engine to run perfectly don't you?

I can't hear anything mechanically wrong either. Certainly doesn't sound as if anything is going to break. Get it tuned and see what happens, Cheers Charlie

I used a Loctitie product.

Mine doesn't have any ticks now after a full rebuild; I did have the exhaust manifolds faces sanded flat and I use high-temperature silicone as a manifold gasket. Perhaps that is the reason, Cheers Charlie

I couldn't agree more with you about genuine parts. Most of the parts made in India and other slave-labour manufacturing areas, have appalling quality control. I had the opposite problem; the original sensor sprung a leak a few thousand kilometres after the rebuild. A really fun job to replace it, when the engine is in the car! Well done for finding the problem, Cheers Charlie

I did the same as Mike H and filled the pump through the oil cooler hose. Prior to that I made a priming can out of PVC drain pipes and using about 10 psi of compressed air, I forced oil into the engine via an oil port; can't remember which port. After about 5 mins, oil was pooling in the heads after escaping from the rockers. When I started the engine the light went out immediately. Don't crank it anymore, or you will bugger up the camshaft; that is how I wrecked my first one.