Ok let’s go through things in a logical order, we maybe covering ground that you’ve already covered but by doing it in an order it sets shit to bed in my mind.
Have you done an OBD diagnostic check with a Testbook T4 or a PScan? If not you might save a shitload of time and money doing so.
You said that you’ve changed the spark plugs, I assume you checked the gaps before installation.
When you say you have a strong spark, where did you take this from…..the coil lead or the plug leads?
If you took it from the coil lead, please check the spark from the plug leads.
If your spark isn’t a nice fat juicy zap you should check the dizzy cap and rotor, may as well check the plug leads too while your at it.
When you say that you checked the timing, I gather you used a timing light, had you at anytime adjusted the timing in recent history? If the answer to these two questions is yes, check the harmonic balancer isn’t failing…has the outer pulley rotated on the centre? If yes replace the harmonic balancer and reset the timing.
So now we should’ve established that we are throwing a big healthy spark an the appropriate time and place.
Let’s now check that all sensor plug connections are properly fitted and going to the correct sensors, whilst doing this we need to make sure all the terminals are clean and free from corrosion. Test all sensors with a multimeter to see that they’re within specs.
Now we hope we have established that the ECU is getting all the correct information to make the car run.
Next is check the fuel system a pump pressure and flow rate test. Failure here and you should try a new filter and retest. Further failure, replace the pump.
Then the injectors, should be tested for flow rate and spray pattern. Failure here and you should ultrasonically clean the injectors and replace the nozzle tips then retest, further failure, replace injectors.
Test signal is getting through to the injectors by plugging in noid lights into the injector harness, if the lights don’t light up when you turn over the engine, then you need to find a wiring harness problem.
Now we have established that there is nothing likely to impede fuel getting in.
When we had the spark plugs out did we do a read of them, did they have deposits, black fluffy carbon or oil shit on them? Was one or more too clean as like steam cleaned?
Do a compression test, and whilst you at it a cooling system pressure test, let’s establish that the head gasket that was new when you got the car is still good now.
Another thing to check is the exhaust, in particular the cat converter isn’t falling to bits and those bits haven’t clogged up the muffler , en exhaust pressure test is the easiest way of doing this it shouldn’t read over 2 psi but I’m the only person I know that has the gauge for this, so I don’t like your chances of finding someone who can do this test, you may have to resort to pulling the exhaust apart and see if it rattles when shook.
I know that you’ve replaced a lot of items, so you need to check that they’re within specs, never trust a new part without checking it, sometimes they’re worse that the ones you replaced, especially if they’re rubbish from China!
Once you’ve ticked all these things off the list and you still can’t get the bastard to go, get back to me and we’ll seriously get all forensic on it’s arse!
"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"
