Maestro Turbo Ignition problems

[Andy]

Hi Pete. Is you ignition switch in good condition? My Ledbury come grinding to a halt with no spark last week and the mechanic that looks after it traced it be a butchered ignition switch.

http://www.ebay.co.uk/itm/3320262731...%3AMEBIDX%3AIT

[E_T_V]

Flywheels are different but only in terms of 2 gap or 4 gap (and starter tooth profile). So you'd still get a spark but perhaps not at the right time or not enough of them if the wrong one was fitted.
Whip the plugs out and crank it on the starter. Does the rev counter "wiggle" when you crank it? if so then it is getting some sort of pulse which will be from the crank sensor. If not check out the crank sensor wiring (as it can get strained by accident). I have a feeling the crank sensor on the O series is the same as later rovers. I think I replaced mine when it went kaput with something from a later car that I had lying around.

[Sussex Pete]

Thanks for the clarification Dan. At least I don't think I have created a problem for myself in that area. I'll check the tacho next time I go through the "troubleshooting" list, although at the mo' I feel like I am going round in circles doing the same tests with the same results and not getting closer to the real problem. I'm also reticent in buying a new ECU in case the fault is really elsewhere and therefore wasting £75.

[Sussex Pete]

I think I am on the final run of getting this fixed! Having spent over two months going round in circles, employing trained auto electricians who came to the same conclusion as me, and speaking to techies at companies who repair the ECU's, who have given me polar opposites in solutions and tests, I can now write with a fair degree of confidence that it is the crank sensor. This is something that Jeff indicated almost two months ago, but I sent myself down wrong paths by believing that the Ignition Analyser was telling me more than it really was.
What I have learned recently and also now proved, with Jez' help, is that the Turbo ECU will run a normal EFi engine. As of today I have now proved or confirmed that the ignition ecu is working, there is a new coil that is ok, new HT leads and new plugs. So, the only thing left that would not allow the coil to create a spark is the crank sensor. I have also learned that as it is an inductive type, the only way to prove if it is working correctly is by use of an oscilloscope. All the ignition analyser was telling me was that there was a complete circuit through the sensor. It doesn't say if the magnetic field is being induced or at the correct level, which is why I have spent so long on a proverbial goose chase.
Looking at suppliers for new ones (ADU7342) Wilcox have got 1 Rover one in stock, but at £71+Vat is a tad expensive. Online stockists are showing them at anything from £26 to £100+. It looks as though they were/are used on Rover 400,800 and V8 Range Rovers, although the RangeRover one has a L suffix on the part number.
Once I've got the old one out, I'll then sort who I will buy the new one from.

[Jeff Turbo]

Glad you're getting there, if it is the crank sensor best of luck changing it as its a bugger with the engine in the car. It did point to the sensor from your original post and as you say it's the only thing left. The diagnostic on crank should have gone out or flickered if not pulsing though. I'm guessing the flywheel was ok that you substituted?. Gimmy a shout when you've finished with my fast checks Pete

[carfix]

Hi Pete.

I am glad you are seeing some progress now. I can see how frustrating it can be particularly when "experts" come up with conflicting advice!!!

Regarding the "L" suffix on the Range Rover parts.

I have found that it simply means that it is now a Land Rover badged part (and probably comes in a Land Rover labelled box) but it will be identical to the original MG Rover part with the same part number.

I have bought quite a few parts for my Rover 400 over the past few years which have had the "L" suffix but are identical to the previous MG Rover part. I guess it happened on the demise of Rover and once the original MG Rover parts disappeared from the supply chain.

All the best, Ian

[Sussex Pete]

....The diagnostic on crank should have gone out or flickered if not pulsing though. I'm guessing the flywheel was ok that you substituted?. Gimmy a shout when you've finished with my fast checks Pete

I think this was the "lightbulb moment" when the latest expert explained that as the sensor is an inductive type, there is no voltage being sent to the sensor. So the LED on the Analyser is purely confirming that there is a circuit in place. As the guy also explained, the only way to see the pulses is using an oscilloscope, a bit of kit I'm sure no-one on here possesses! The flywheel is a new (from Rimmers) early 800 type, that allowed me to fit a bigger clutch. I will be checking quite carfully once the old sensor is removed about how they fit together just to make sure in my own mind that I have created a problem for myself, and recognising that Dan has already confirmed that they are all very similar except for the number of gaps in the relucter ring.

I'm hoping to get the Analyser back to you sometime next week once I've got this all sorted finally. Thanks for the loan, even if it did send me down some wrong paths!

[Sussex Pete]

Got the crank sensor out of the block - although I dread to think how I'm going to get another one in! - and was thinking about the wiring connector. This was because some %%**^£@ person decided to cut the wires at the connector and then twist them back together again before I bought the car. So during my renovation I fitted a waterproof 2-wire plug and socket to the circuit. As I will now be fitting a new sensor with the correct socket, I decided to check a spare maestro harness to see what is involved in recovering the plug to mate to the sensor and connect that to my harness.
What I found was that the wires from the sensor plug are shielded all the way to the ECU plug. I'm pretty sure that mine hasn't got any shielding on that circuit. Could this explain why I wasn't getting a signal from the sensor??

[E_T_V]

It certainly won't help. The sensor signal is tiny and easily disrupted by electrical noise. That's why it is shielded to prevent electrical interference with the signal. I can't remember where the shielding runs to. I think it is all the way back to the ECU, but certainly it is connected to earth.

[Sussex Pete]

As of this moment my ignition system consists of:

• New crank sensor (giving exactly the same resistance as the old one at both the sensor plug and ECU plug)
• ECU - confirmed as working correctly (by fitting to an EFi and engine starting and running well)
• New coil (3rd one)
• New HT Leads
• New Distributor cap
• New Champion RN7YC plugs
• All tests so far have been from the coil to exclude possible issues with dizzy cap and/or rotor arm

If, when I have managed to refit the crank sensor and connect everything back together again, I still don't see a spark then I am at a total loss to point to a reason. The only thing that still bugs me is that fact that I'm using a new flywheel (PSD101580) and am bothered that the crank position sensor may not be far enough inside the reluctor ring for the magnetic field to be created. Using a long arm allen key, I have seen that the back face of the reluctor ring is at least 5mm further in than the tip of the sensor. Is that enough clearance and the tip position is correct for the magnetic field to be created, or should I be looking to shave a millimetre or so from the face of the spacer plate to move the sensor further in?

[Jeff Turbo]

Then you may have to remove the gearbox to double check, and possibly put the old flywheel back on

[G Force]

some %%**^£@ person decided to cut the wires at the connector and then twist them back together again before I bought the car. So during my renovation I fitted a waterproof 2-wire plug and socket to the circuit. As I will now be fitting a new sensor with the correct socket, I decided to check a spare maestro harness to see what is involved in recovering the plug to mate to the sensor and connect that to my harness.

Apologies if you have already considered this but it important that the wires in the crank sensor harness plug are oriented correctly to the corresponding wires of the sensor itself. The physical one way only connection of the standard male and female plug usually ensures you can’t get it wrong. The problem occurs when the wiring has had to be repaired it presents an opportunity for the wires to become transposed. Unfortunately I don’t recall it being documented anywhere as to the correct pairing but it should be easy enough to refer to your spare harness and new crank sensor.

Regards, Gary

[Jeff Turbo]

Apologies if you have already considered this but it important that the wires in the crank sensor harness plug are oriented correctly to the corresponding wires of the sensor itself. The physical one way only connection of the standard male and female plug usually ensures you can’t get it wrong. The problem occurs when the wiring has had to be repaired it presents an opportunity for the wires to become transposed. Unfortunately I don’t recall it being documented anywhere as to the correct pairing but it should be easy enough to refer to your spare harness and new crank sensor.

Regards, Gary

OO that's tiny writing Gary, need my glasses to read that lol

[Sussex Pete]

Apologies if you have already considered this but it important that the wires in the crank sensor harness plug are oriented correctly to the corresponding wires of the sensor itself. The physical one way only connection of the standard male and female plug usually ensures you can’t get it wrong. The problem occurs when the wiring has had to be repaired it presents an opportunity for the wires to become transposed. Unfortunately I don’t recall it being documented anywhere as to the correct pairing but it should be easy enough to refer to your spare harness and new crank sensor.

Regards, Gary

Its a good point Gary, and when I carried out the initial repair I also used wires with the correct colours so that I was connecting like to like at both ends. With short tails on the ECU plug, those wires didn't change position, just a short infill wire to remove damaged ones that could have allowed a short. Also added a 2-pin waterproof plug and socket at the sensor end as that was missing entirely when the car was purchased (wires were just twisted together, so its amazing it ran at all!)

[G Force]

You would have thought that if the physical positioning of the crank sensor with the 620 / 800 turbo flywheel retro-fitted was an issue it might have been flagged up by the guys that have been down that road?

I don’t think that you can see the physical location of the sensor in relation to the reluctor ring even with the gearbox removed. The armature of the crankshaft sensor protrudes about 3/4 of its own length into the reluctor ring, thinking back from distant memory as it is visible on the 1.6 engine with VW manual transmission removed.

Regards Gary

Hopefully typed back in big for Jeff as he’s lost his spec’s