Thread: V8 Non start after rebuild

Rule 1 with V8's and 14CUX management, DON'T try and start from cold with a low battery, it'll flood the poor little plugs. This would be made worse by new cam followers that aren't fully pumped up, not allowing valves to open enough which = less intake air. Try pulling the plugs and replacing them, and charge the battery fully.

JC

In a 14CUX ECU cranking fuel (cranking conditions determined by engine coolant and fuel temperature sensor inputs to ECU) is set by the ECU’s temperature map. LR constructed the 14CUX temperature map so cold & warm-up fuelling is very rich to the extent the risk of start up flooding is dangerously high and fuel economy shocking during warm up. LR must have thought were all driving around the Scottish Highlands in the middle of winter.

The ECU also needs to see some RPM (minimum 50RPM I think) to know its cranking so ensure your alternator is correctly wired up.

Do rush out and buy it a new 700cca battery, it will love you for it. Also check all the earth cabling between the battery and the block are present and correct.

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.

Originally Posted by justinc

Rule 1 with V8's and 14CUX management, DON'T try and start from cold with a low battery, it'll flood the poor little plugs. This would be made worse by new cam followers that aren't fully pumped up, not allowing valves to open enough which = less intake air. Try pulling the plugs and replacing them, and charge the battery fully.

JC

The battery had been fully charged overnight before I tried it, and the plugs were brand new.
After trying a few times to get it to start, and I'd got to the click, I put the battery back on charge for 5 hours, pulled each plug and cleaned it.

After charging, I pulled the fuel pump relay, then tried each plug in turn to check for a spark (half a second burst on the key each time), and all was good. Pulled the starter motor, cleaned (plenty of life left on the brushes) and checked for operation direct from the battery.
Disconnected the starter earth lead and cleaned, reconnected.

When trying the battery, there was no huge voltage drop. It was sitting at 12.6v before cranking and dropped to 12v during cranking.

Originally Posted by cockie55

.....The ECU also needs to see some RPM (minimum 50RPM I think) to know its cranking so ensure your alternator is correctly wired up.

This may be the problem. It was probably only turning at 50rpm or thereabouts. For the alternator, I checked the connections (I think there's 3?) and couldn't see a problem.

Originally Posted by bee utey

Do rush out and buy it a new 700cca battery, it will love you for it. Also check all the earth cabling between the battery and the block are present and correct.

I am tempted with the battery. Everything I have read points to a 650+ CCA battery required, so a 400 seems a little pathetic.

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.

I followed the instructions on RAVE (and I'm going from memory here as I'm not at home, so forgive me if I misquote), which said that initial timing after rebuild was to be 6deg BTDC, which was to be achieved by getting the timing mark at 6deg BTDC on the crank pulley with the rotor pointing at the No.1 position.
I also measured my own TDC mark on the crank pulley rather than rely on the existing mark.

When I get home, I think I'm going to try a beefier battery as a start point and see where I get from there.

Thanks for the replies so far, any further guidance appreciated.

Originally Posted by sheerluck

The battery had been fully charged overnight before I tried it, and the plugs were brand new.
After trying a few times to get it to start, and I'd got to the click, I put the battery back on charge for 5 hours, pulled each plug and cleaned it.

After charging, I pulled the fuel pump relay, then tried each plug in turn to check for a spark (half a second burst on the key each time), and all was good. Pulled the starter motor, cleaned (plenty of life left on the brushes) and checked for operation direct from the battery.
Disconnected the starter earth lead and cleaned, reconnected.

When trying the battery, there was no huge voltage drop. It was sitting at 12.6v before cranking and dropped to 12v during cranking.




This may be the problem. It was probably only turning at 50rpm or thereabouts. For the alternator, I checked the connections (I think there's 3?) and couldn't see a problem.



I am tempted with the battery. Everything I have read points to a 650+ CCA battery required, so a 400 seems a little pathetic.



I followed the instructions on RAVE (and I'm going from memory here as I'm not at home, so forgive me if I misquote), which said that initial timing after rebuild was to be 6deg BTDC, which was to be achieved by getting the timing mark at 6deg BTDC on the crank pulley with the rotor pointing at the No.1 position.
I also measured my own TDC mark on the crank pulley rather than rely on the existing mark.

When I get home, I think I'm going to try a beefier battery as a start point and see where I get from there.

Thanks for the replies so far, any further guidance appreciated.

I would replace the plugs. IME Once they are soaked, they aren't any use for a cold start. 400CCA isn't sufficient either.

One other thing, are you CERTAIN you haven't mixed up the fuel rail temp sender plug with the coolant temp sender plug. It can and HAS happened I have had a vehicle flat trayed in with a non starting/ poor running condition due to this. The ECU was getting some silly numbers from the mixed up sensors. Someone had replaced the head gaskets and plugged the wrong sensor plugs in to the wrong sensors. After a week of trying to get it running it was sent down to me...didn't THEY have a fit when It was runing OK in 3 minutes...


JC

Listen carefully to the fuel pump. It should run on for a moment after you stop cranking. If it doesn't I would suggest tracing the wiring around the coil. There is a small white/black stripe wire that MUST be connected to the coil negative. That sends engine rotating signal to the ECU. Without it, no injection. On some cars this wire is white/blue stripe and can be connected by an inline resistor near the coil. Use a LED test light to look for pulses at an injector plug while cranking.

I doubt you need alternator signal to start, that is what the coil negative wire is for.

Originally Posted by justinc

I would replace the plugs. IME Once they are soaked, they aren't any use for a cold start. 400CCA isn't sufficient either.

Ok, so that's an extra set of plugs and a new battery on the shopping list for Friday afternoon then.

Originally Posted by justinc

One other thing, are you CERTAIN you haven't mixed up the fuel rail temp sender plug with the coolant temp sender plug. It can and HAS happened I have had a vehicle flat trayed in with a non starting/ poor running condition due to this. The ECU was getting some silly numbers from the mixed up sensors. Someone had replaced the head gaskets and plugged the wrong sensor plugs in to the wrong sensors. After a week of trying to get it running it was sent down to me...didn't THEY have a fit when It was runing OK in 3 minutes...


JC

JC, are you describing the sensor at the front right of the fuel rail that has a plug very similar in shape to the injectors, and the temperature sensor that sits below and to the right of that (has a single flat "prong" to attach to)? I remember the plugs being quite different in shape and difficult to get round the wrong way, but I'll put it on the list of things to eliminate.
I hope it is something as silly as that though.

Originally Posted by bee utey

Listen carefully to the fuel pump. It should run on for a moment after you stop cranking. If it doesn't I would suggest tracing the wiring around the coil. There is a small white/black stripe wire that MUST be connected to the coil negative. That sends engine rotating signal to the ECU. Without it, no injection. On some cars this wire is white/blue stripe and can be connected by an inline resistor near the coil. Use a LED test light to look for pulses at an injector plug while cranking.

I doubt you need alternator signal to start, that is what the coil negative wire is for.

Fuel pump was definitely running on, though for no more than half a second or so.
I did tighten all of the spade connectors to the coil terminals as they were a little loose; there was 3 on the negative side and 2 on the positive (though that may have been round the other way....!). As I had the coil out whilst cleaning part of the engine bay it's possible I disturbed something. Something else to put on the "to be eliminated" list.

Thanks again.