V8 Engine Issue

[ajh]

I'm having a rather frustrating problem with a 1999 V8. The two symptoms include the air suspension not levelling and the vehicle starting then running for a few minutes and stopping. Then it will not re-start for at least an hour but after that it will restart fine. I just discovered that moving the bundle of wire in the engine bay that goes through the firewall seems to cause the stall.

Disconnecting the battery for a few minutes doesn't seem to let it re-start which is a bit confusing.

Any suggestions on what to try to possibly at least get it able to start more often to make the debugging even possible?

[ajh]

I also get an open circuit P0202 on cyl 2; changed the injector already.

[FridgeFreezer]

I'd check that wiring loom closely.

[ajh]

Any idea on a list of things that if the wire is broken will cause this behaviour? To get it to re-start after a stall I apparently need to disconnect the battery for hours and then reconnect it. This is seriously limiting debugging.

[ajh]

Along the way I did fine one spark boot that had pulled down (not on #2, on #3) and was arcing from the cable to the valve cover, and replaced the ICF which was making more noise than it probably should but it is still stalling out. This is the same one where the XYZ switch split and had to be replaced... everything seems to be happening at once.

[FridgeFreezer]

No idea, the RAVE manual wiring diagrams might be a good way to scare yourself through. They tend to show all the connectors, joins, junctions, etc. as well as the actual circuit diagrams.

[V8 Freak]

This might be sending you away from the real problem, but if you change the plugs for a fresh set (After stalling and failing to start) does it run?

I recall having issues with some spark plugs, moreso with some brands than others. Once "wet" they would not fire the engine....

I can't see how a running engine, would stall and not start for an hour if it's a wiring issue? How do the wires mend themselves temporarily?

Sounds more like overfuelling during warm up cycle and a sort of flooded issue requiring time to re-start and run.

Is this 14CUX / Hotwire or Flapper?

Neil

[FridgeFreezer]

I can't see how a running engine, would stall and not start for an hour if it's a wiring issue? How do the wires mend themselves temporarily?

Chafing against something metal, then moved by the vibrations of the engine starting / stopping etc., could be affecting a sensor reading or anything - could be shorting the coolant sensor making the ECU flood it with fuel... could be any number of things if the wiring loom is dodgy - until that's removed from the equation it's going to be hard to be sure what else, if anything, is wrong.

[V8 Freak]

But plugs out could help diagnose over fueling / flooded?

[FridgeFreezer]

Butt plugs?

Yes removing the plugs might help, but if there's an obvious fault with the main wiring harness (which could easily be the root cause) why go hunting round until that's been sorted out?

[acamato]

Check the Crank Position Sensor. When they fail, they have issued when they get hot, when they cool back down they work.

Check for fuel and spark when you have the problem.

[dave88sw]

As above. In my experience, a failed crank sensor will not show a fault on diagnostics, the car just assumes the engine is not turning over. You can go into live data and look for an rpm signal whilst cranking though

[ajh]

Yes, the final issue was the CPS. So this one vehicle needed an Injector, the XYZ sensor, the O2 sensors re-wired as the plugs corroded out, a cleaning of the ICV, and the CPS, and we replaced the BCU/ECU with a known working set due to the immobiliser going off randomly.

Thanks for all the input; it's always frustrating when multiple issues present at once. I now know a lot more about the V8s... and still prefer 200/300s.