[greddm]

I've discovered that, in addition to not having fuel pressure, I also have no spark after reassembling my engine. Nice. I checked the ignition fuse and it's fine. I also removed the HT lead from the distributor and held it 6mm from engine block so see if I had a spark (I didn't). Seeing that I have neither fuel nor spark I'm wondering if there is a larger problem at work here - perhaps a wire pulled loose while I was working on the engine? Is there a common component between the fuel pump and the coil that I could check?

One other bit of info that might be helpful is that while the engine was apart, (negative battery lead disconnected) I moved something and grounded out the battery and there was a spark - I don't remember exactly how or what all was in contact, but maybe that fried something? Seems like it would have just blown a fuse.

Feeling like a rank amateur at this point.

 

[95classiclwb]

your spark controls the injector duty cycle, thus if you have spark you open the injectors. coupled with working fuel pump and the rest works it self in theory.
to summarize trace your power concern and if you have fuel delivery...…...

 

[Classicpain]

While looking thru my hardcopy of the '95 factory manual (haven't found a download-able copy of the ’93 RAVE manual yet) to findinfo on dis-assembling my dizzy, I stumbled across an ignition diagnosissection in the “Electrical” section, at the very end of the manual. Not in an “ignition”section, but in the Electrical section. It has a VERY clear and step-by-stepprocedure for checking voltage at various points in the ignition system, todetermine where a fault lies. Take a look at it. I’ll record the section/pageand get back to you if you can’t find it.

 

[leftlanetruckin]

One other bit of info that might be helpful is that while the engine was apart, (negative battery lead disconnected) I moved something and grounded out the battery and there was a spark - I don't remember exactly how or what all was in contact, but maybe that fried something? .

Moved something? Hmmm OK
Yeah in theory it should blow a fuse and everything is happy. In reality though, that isn't the case a lot of the time.
You're going to have to check everything one step at a time, and see what you blew.

Martin

 

[greddm]

Thanks Classicpain, I found the guide and will go through the step tonight. One question I have is that I noticed my distributor does not have the amplifier unit bolted to the exterior – It just has two wires and a connector. I'm assuming it is not the dizzy that came with the truck since the original 3.9L engine has been swapped for a 4.6 out of a discovery. Will that affect any of the test results? Specifically test 3 v4 shows connecting a bolt on the amplifier unit to ground. Can I just use the casing of the dizzy instead?

Thanks

 

[greddm]

your spark controls the injector duty cycle, thus if you have spark you open the injectors. coupled with working fuel pump and the rest works it self in theory.
to summarize trace your power concern and if you have fuel delivery...…...

I thought the ECU (14cux) controlled the injectors and the spark was all mechanical?

 

[greddm]

Ok, I've done ignition tests 1-5 from the manual, (screen shots attached for reference) here are the results:




Test 1
No Spark. No surprise here.


Test 2
• V1 – 11.9v
• V2 – 11.7v
• V3 – 11.7v
• V4 – As mentioned earlier, my dizzy does not have an external amplifier unit (see pic) so I wasn't sure how to complete this test


Test 3
Here's were I saw some discrepancies:
• (with ignition OFF) Batter pos. to HT coil neg. should be 0v but I show 11.98v
• (ignition ON) Should still be 0v but I show 0.12v


Test 4
Again, I don't know if this is apples to apples since I don't have the amplifier (external, anyway) - So I connected to the two wires coming from the dizzy and I get 3.47k Ohm which is with the specified range.


Test 5
No spark




So where does this leave me? Based on the info in the manual it says I need a new amplifier, which as we have established, I don't have. Does that mean I need a new Distributor?

 

[JS5D]

Ok I have a different year (older) but I would think that you need an amplifier. The way the system works is that the coil gets a + feed and then the negative side gets switched between open and ground so you get a pulse wave on the + and - of the coil resulting in a high voltage spike on the ignition leads etc.

The two wires from the distributor are connected to a small signal coil inside the distributor which creates a tiny pulse from the trigger wheel on the distributor. What you measured is the resistance over the signal coil which seems to be ok. That tiny pulse (which you can only measure with delicate equipment like a scope) goes to an amplifier (either mounted on the distributor or separate on the mudgaurd) that in turn creates the proper grounding signal for the coil. In effect this is just an electronic replacement for the mechanical points as used on old cars.

Now I am not familiar with newer Range Rover classics and it could be that the (tiny) distributor signal goes the the main ECU to be amplified, but I don't think this is the case and the whole ignition system is independent of the fuel delivery (other than a one-way signal for the ECO to use).

So from your description your amplifier might have failed, which is not uncommon. Did you check the resistance of the coil? They can fail also.

 

[Classicpain]

Agree with JS5D, if you did the tests per the procedures andit indicates you need an amplifier, that’s the easiest thing to replace. Theimage of the dizzy looks like a Lucas dizzy so you know you’re not dealing witha Mallory or anything, so that’s good.

 

[greddm]

Guys, I believe I have solved all the mysteries! I removed the coil last night because I had ordered a new one to see if that would fix the problem. Low and behold what did I discover tucked away attached to the coil bracket? The amplifier. It’s remote. But the real face-palm moment came when I also found the connector was disconnected... just a stupid disconnected plug. In my defense it was not visible before I removed the bracket but I must have somehow disconnected it during my tear down of the engine. So between that and the new fuel pump I installed I’m hoping it fires up tonight. I still need to replace the fuel filter so I didn’t give it a go last night.


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