Thread: V8 Non start after rebuild

For a start after the injection has been broken into, you have to prime the system several times by turning the ignition off then on and listening to the 3 second burst and waiting until it completes. I do it six or seven times. It cannot hurt anything as the regulator will spill excess back to the tank.

If the engine is flooded the ECU has a "clearing " mode by surprise surprise holding your foot flat to the floor while cranking.
Regards Philip A

Question, did you install the dissy with the crank spot on TDC?
If you installed the dissy with the crank at 6 BTDC you could be a tooth out, Regards Frank.

I should have said the engine cranking is wired from coil not the alternator (as bee utey correctly pointed out). There is a 6.8k ohm resistor in this circuit (black/white wire) that produces a voltage pulse of about 7 volts to the ECU so also check that resistor/output voltage. Except for this externaly powered input the ECU has defaults for all other inputs in the event they fail so engine can still run, albeit not well.

You seem to have good fuel pressure and spark and it cranks. Therefore if initial timing proves OK is there any chance the ECU may have got accidently fried at some point during the rebuild??? Checking ECU output to injectors and idle stepper motor followed by ECU input voltages (sensors powered by ECU) from say MAF, ECT and TPS is a good guide to ECU health.

I have a leftover 14CUX ECU if you need it, I switched to megasquirt long ago

Originally Posted by bee utey

Aerostart?

I think that's the next option, though one thing did occur to me, which is that the Disco has been sitting for nearly 8 months, with fuel of unknown quality in the tank. I've seen a couple of threads on how quickly fuel goes stale, so I'll be adding a couple of jerrycans worth of fresh fuel just to eliminate that too.

Originally Posted by PhilipA

For a start after the injection has been broken into, you have to prime the system several times by turning the ignition off then on and listening to the 3 second burst and waiting until it completes. I do it six or seven times. It cannot hurt anything as the regulator will spill excess back to the tank.

If the engine is flooded the ECU has a "clearing " mode by surprise surprise holding your foot flat to the floor while cranking.
Regards Philip A

I did give it 5 goes on the fuel pump before the first start attempt, then a quick check for leaks, then a burst on the starter.

Originally Posted by cockie55

.....You seem to have good fuel pressure and spark and it cranks. Therefore if initial timing proves OK is there any chance the ECU may have got accidently fried at some point during the rebuild??? Checking ECU output to injectors and idle stepper motor followed by ECU input voltages (sensors powered by ECU) from say MAF, ECT and TPS is a good guide to ECU health.

I kept the battery disconnected for all but the last couple of days. I can only think of one event where there was any kind of sparking or surge, and that was where my mate was underneath trying to remove the heatshield from the starter motor before I'd finished re-disconnecting the battery, and managed to wiggle it too close to the starter terminals. Small spark and a couple of swear words, but would that have been enough to fry the ECU?

Originally Posted by jazzaD1

I have a leftover 14CUX ECU if you need it, I switched to megasquirt long ago

If the answer to my question above is "yes", then I'll be back to you.

Originally Posted by justinc

The ECU temp sender input is the same plug and socket shape as the fuel rail input, the plugs will interchange. It is near the single pin temp sender for the gauge on the passenger side front of inlet manifold top face, near no.1 cylinder intake runner.

JC

I vaguely remember there being 3 leads to plug in, and am reasonably sure I got everything back in the right place, but will definitely give it a look when I'm home.

When I have flooded an engine after working on the car/rebuild, my farther showed me a way to reuse the same plugs without having to wait for time to solve the flooding problem. He took out the plugs which were wet. Placed the plugs on a sheet of metal (Milo tin lid) and set fire to the plugs. Burns off the petrol and warms the plugs, you might have to wait until the plugs cool a bit before you can handle them.

WARNING DO NOT DO THIS AT HOME BY YOURSELF CHILDREN. Matches and petrol are a dangerous combination.

This might be like telling you grandmother how to suck eggs, are you sure of your valve timing? spark timing? fuel timing? If you have flooded it pretty much rules out the fuel availability question.

If your battery is going click, click after a few cranks and it has not come good after a night on the charger then I think your up for a new battery

It is my understanding that allowing the engine to turn on the starter alone when a new camshaft and lifters have been fitted will quickly see the camshaft ruined.

The engine must be fired up straight away and then run at between 2000 to 2500 rpm for a good 20 minutes and no idling at all during this time.

I appreciate that your engine will not start, so I am only offering some well intentioned advice.

Ron.

Originally Posted by Tank

How did you setup the dissy when you installed it, you say it is set at 6 degrees BTDC, how did you get it to 6D, the correct way is to turn the engine till on TDC, #1 piston valves both closed, slide in dissy so that rotor buttun points to #1 terminal, when the engine starts you adjust the timing using an Timing light.
Correct me if I'm wrong, have you put the dissy in with the timing mark at 6d or TDC, if so remove the dissy and put it in at TDC, Regards Frank.

Frank,

As I said, I followed the instructions on RAVE, which I have attached the relevant page of.

My memory was a little defective though, I said 6deg, it's actually 3deg, but the methodology was correct:

1. Point the timing pointer at 3deg BTDC.
2. Stick the dissy in it's hole in such a way that the rotor ends up pointing at no 1.
3. Start