range rover dead...

hello, Would the ignition module from a 3.9 fit on the distributor of a 1990

3.5. I think the spark is weak, and have changed the power resistor. Seems as though the spark is in time if a little weak.
Reply to
bern
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Reply to
Paul Coley

Possibly.... There is a good chance they have the same distributor but the 3.5 did have a few variations and there's no guarantee that the distributor is original.

A 1990 RR should have the amplifier module mounted on the side of the distributor and SHOULD be the same as a 3.9. What power resistor have you changed ? There shouldn't be a power resistor associated with the ignition on these distributors. If you have a ballast resistor in line then that is your problem or you have the wrong coil/distributor/ amplifier set up for the model year.

cheers

Dave W.

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Reply to
Dave White

Reply to
bern

On or around Wed, 25 Aug 2004 23:58:12 +0100, bern enlightened us thusly:

when mine died unexpectedly like this it took me quite a lot of swearing and money and time and effort to discover that the rotor arm was shorting from the top to the inside, by some invisible means. Cost me an arm and a leg to discover that, too - bought a new trigger unit for the inside of the dizzy, 'bout 70 quid, buggrit.

The 3-wire connector is not unusual, as you've found, only 2 get connected.

check that you actually get a spark in the plug, not just the leads...

Reply to
Austin Shackles

Working on the principal that you have compression, fuel and spark it would suggest that the spark either isn't big enough, it's happening at the wrong time or the fuel mixture is wrong.

A 1990 3.5 shouldn't have a ballast resistor IIRC but then a 1990 RRC should be a 3.9 as the 3.9 replaced the 3.5 in August 1989. You sort of suggest you've done this already but the first thing I'd do is run a temporary feed from the battery +ve to the coil +ve. This will rule out any problems with any ballast bypass wiring and make sure the coil is getting all the power it needs. You'll need to leave the existing wire intact as the existing +ve at the coil also connects to the amplifier.

Time the engine manually - stick a welding rod or similar down the spark plug hole in cylinder 1 and make sure that TDC on the crank pulley matches TDC on the engine. (You'd be amazed how far out some of them are). Then check the ignition timing against that.

I'm assuming from the 3.5 engine that it's running a flapper EFi, that being the case make sure you diconnect the electrical connector to the cold start injector. Ideally you should leak test the injector as they do have a record of jamming open. When you try running it on gas, make sure you disable the petrol pump before you start cranking. The easy way to do this is by either removing the fuel pump relay or disconnecting the 3 way connector near the fuel filter in the RHS rear wheel arch. This will prevent the cold start injector (or any of the other injectors that may be leaking) from screwing up the gas mixture.

Never try starting a flapper EFi using short bursts of cranking, every time you start cranking again the cold start injector will fire for another 10 seconds (unless you've disconnected it).

Burn the plugs off on a gas hob or similar to get rid of any residual fuel and replace them while they are still hot as this will discourage further flooding. Don't burn your fingers though !

If you are seeing petrol at the throttle body there's something wrong with the fuelling. The fuel (petrol) is injected directly above the inlet valves for each cylinder and the trumpets inside the plenum chamber ensure that the fuel charge stays put. The only injector that can get to the throttle body is the cold start injector as it is mounted on the side of the plenum chamber. I've seen cold start injectors malfunction so badly that neat petrol has started dripping from the end of the exhaust !

One last thing to consider (although the gas problem probably rules this out) try draining some fuel out of your tank into a clear bottle and let it stand for 10 minutes. If you see a line appearing in the bottle you have water in your fuel, if you don't get a line appearing then sniff the bottle and make sure it smells of petrol ! I once spent several hours trying to restart a damp 3.9 only to find that the petrol tank was actually full of water :-)

HTH

cheers

Dave W.

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Reply to
Dave White

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