Fault codes

[kelvin]

I've just rebuilt my engine after a major failure (VN computer). Same specs, but now runs VERY rich, black soot out the exhaust. No obvious faults, the only thing I figured could cause that much overrich would be a MAP sensor showing full throttle. It's flashing 12 (OK) with the appropriate terminals shorted. But when I unplug the MAP sensor it still flashes 12. I would have thought fault code 34 or something. Why is it so. Also any help to track down the rich problem.

[VL400]

Does unplugging the MAP make any difference to how it runs? Might be worth logging it (if you can) and see what all the sensors do - could also be a coolant or intake temp sensor thats reading very cold.

[antus]

Yep, or bad fuel reg or blocked or reversed fuel pipes causing high fuel pressure.

[kelvin]

I'd like to log it, but I'm not that clever, yet, may need to work on that, but would obviously help. It's difficult to try unplugging MAP as the car only runs for a short time then fouls up. I need to unplug the fuel pump relay for a while to clear it out. It must be something I've done wrong in putting the wiring loom back as it was runnimg fine before.

[VL400]

Def check what antus suggested too, a blocked (squashed or kinked) return line will cause it to run pretty rich.

[vn5000]

Have you tried starting and letting it run for 30 sec without the map sensor connected .If you have and it still doesnt log a fault code i would be suspecting a faulty ecm .Also try checking the map output voltage at the ecm with engine stopped and running.