Its broken.

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LetsHopeItFits said:
Well Im going today to pay the bill and push it out of their yard so I can get it on the weekend.
Thankfully theyve decided not to charge me any labour, so just for the sparkplugs, which is kind of them.
So, has anyone got any useful links to what all the wires should be doing?
Ill start by testing the battery voltage and the earth, and then all the wires which connect to the coil. How do I test the ignition amp? Thanks
Click to expand...
I take it you referring to the coil wiring.
A copy from my Haynes manual shows what is connect to the top of the coil.

Black is 12v to the coil + via the spider immobiliser.
White from + to the amp terminal 3.
White from + to the suppressor.

On other side of the coil.
White to the amp terminal 1
Black/white to the EFI ECU via a resistor and on to the trip computer (manual gearbox only) via a resistor.

So all very simple.:)

upload_2023-2-22_18-21-45.jpeg
 
Can someone confirm the correct part number for the ignition amp? Or even better, a link to the correct item on ebay/etc? They seem pretty cheap so Ill just replace it
Thanks!
 
Finally got it back from the garage with a battery flatter than the netherlands. It took over a day to recharge it, dropped the battery in and it turns over but doesnt start.
Garage told me theyve fixed the spark, but now it wont fuel. Ill check the fuel pressure and see if it runs on EZ start.
They also said theyve not done the timing, so they might have put the dizzy on the wrong way. Ive found an old timing light in the shed, no idea if it works.
Its had an LPG kit on it in the past, but its been removed. The garage reckon its something to do with that.
 
Thanks. Ive had a look and theres no fuel pressure and the fuel pump isnt making a sound. Started to unscrew the fuel pump, but the last screw is rusted solid and Ive not got a drill. Soaked it in WD40 and will try again tomorrow.
The fuse isnt blown, so either the pump is dead, or theres some other issue.
 
Right, did a proper bodge to try and get it to run.
Recharged the battery, hard wired the fuel pump to another battery. Lots of fuel pressure, turns over but doesnt run. Spark is working as it should (but timing is out)
I guess the fuel injectors arent opening, so ECU?
 
Okay, heres what my mate whos helping me has said.
"The first thing we noticed was that the fuel pump isn't running
So multi meter on the pins. Getting about 9v at the fuel pump. (Is this correct?)
Tested the fuel pump with a 12v sourge direct to the pins, and the fuel pump runs.
Therefore, assuming a bad ground, we put a ground from the fuel pump ground pin to the chassis. Trying againwith the normal battery, the pump still doesn't run.
Any ideas why the fuel pump isn't running?
With the fuel pump issue in mind, we tested spark, spark is good. Forcing the fuel pump to run and seeing good pressure to the fuel rail, we tried to start the it, and we got nothing. Turns over, but not even sounding like it'll start. It is just turning over.

Any ideas about what this could be?"
Thanks!
My guess is that its the injectors, which makes me think its something to do with the LPG kit, because surely all 8 injectors wouldnt be broken?
Could it be the ECU?
Thanks!
 
Okay, it has been known that the EFI ECU is faulty but its rare I believe. The ECU controls the fuel pump relay and that that also has been known to fail so i’d check there’s output voltage from the ECU to the relays coil, also from the relay contact away to pump.
I assume you have checked the inertia fuel pump cutout isn’t open circuit and isolating the supply to the pump, its on the bulkhead down behind the washer bottle.
 
Its not the pump thats the problem. Well it is, but its not the main problem. The issue with the pump is that its getting 9v instead of 12v, but when given 12v it still isnt running.
Will check the relays and the ECU too, just in case.
Even will ample fuel pressure at the rail, it isnt firing. Now given that the garage who had a look at it couldnt fix it, Im going to check that the firing order is still correct and that the timing isnt so far out that it isnt running at all. I think that the injectors arent opening due to the leftovers of the LPG kit, but further investigation is required
 
Firing order is correct, spark is working, timing isnt out, will not run on EZ start.
Fuel relay pins all showing about 1v iirc.
Its been 3 months since its moved under its own power. I just want it to drive...
The petrol might be off
 
Right, bypassed half the loom to hardwire the fuel pump, so now there is plenty of fuel pressure.
Tested the voltage for the injectors and its 0.1v at best, so they arent opening. Any ideas?
Thanks
 
If it won't even pop or fire on easy start, fuel isn't your problem - either nothing is getting into the cylinders, or there is nothing to make it go bang.

Compression test first. Make sure air gets in, and gets squished properly.

Then check you have decent spark the ENTIRE cranking time. Then make sure the timing REALLY is correct (if it was off, I'd at least expect a backfire or pop if the spark REALLY was working!). I'd go over the whole system, making no assumptions and using no preconceptions - it's easy to get wrong in the same way, repeatedly.

Even better, if you get an inline spark tester, you can see if it works under compression - sometimes spark "leaks out" the easiest path, if the cap is faulty (for example).

I'd leave the fuel pump disconnected and try get a get a pop on easy start, in case its dumping raw fuel into the cylinders.

After you can get it to fire/pop etc, THEN worry about the fuel getting in.

There is also the wire from the coil to the ECU that it uses to detect the spark and trigger the injectors - if it's not getting that signal, it will never open the injectors. You should have 12v on one side of the injectors, and the ECU earths the other side to open them. You can watch it with a multimeter. Each sides set of 4

Best thing for these old things is Rovergauge. You can tell if the ECU is getting sgnals, what they are and how it's responding.

Once again, I'd like to see a vid of it cranking, with decent sound :)
 
AllanWorms said:
There is also the wire from the coil to the ECU that it uses to detect the spark and trigger the injectors - if it's not getting that signal, it will never open the injectors.
Click to expand...
Is this the same wire that does the revcounter? The rev counter was playing up and then stopped working a while ago
 
Actually, I've never checked how the rev counter functions on a V8, but it wouldn't surprise me if it used the same signal. The Engine ECU does NOT have an output to the tacho. The wire comes off the coil, goes through a resistor to keep the signal clean/arrest spikes and to the ECU, it might split off to the tacho along the way.
 
LetsHopeItFits said:
Is this the same wire that does the revcounter? The rev counter was playing up and then stopped working a while ago
Click to expand...
The alternator supplies the signal to the rev counter from its terminal W, via a white wire to a ‘phase tap resistor’ and then on to the rev counter head a with white-grey wire.
According to the workshop manual. :)
 
LetsHopeItFits said:
Right, bypassed half the loom to hardwire the fuel pump, so now there is plenty of fuel pressure.
Tested the voltage for the injectors and its 0.1v at best, so they arent opening. Any ideas?
Thanks
Click to expand...
Again the EFI ECU looks after the operation of the fuel injection, so does the the ECU have the 12v supplies, from the battery and from the ignition coil.
 
The ECU is working, at least to some degree, because theres power to the idle control valve.
Ive noticed that the garage have put the coil in upside down. Theres spark, so its working somewhat. Other than making the spark, does the coil serve any other function?
 
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