Have a on going problem with my 4x4 saph, the car is acting funny and the problem seems to keep changing. It used to be a bit hard to start but once started it started straight away again, now the car has decided to really act up. The car is currently off cylinder no4 and when you remove the plug lead the car stops, doesn't do this with the other 3 leads. There is spark at no. 4 though but when you unclip no 4 injector it seems to make no difference but when you put it back on again you'll hear it pulse for like one cycle, other prob I found is at the map sensor plug I get 2 feeds of 5v when ignition is on. Anyone any ideas on what's going on? Bad chip perhaps?

 

The 4x4's have trouble with the standard loom connector plugs at the rear of the engine bay, quick fix seems to be cut the plugs out and solder the wires directly to each other.

 

Tried the plugs on the bulk head but no difference all the connections are nice and clean, tbh I think it may be the chip or brain that has gone a bit funny,

 

Have you got access to another ecu to try? It sounds like your ecu has the same problem that my L8 had and maybe a little more but mine went down on number 2 and 3, it wasn't supplying an injector pulse to them (Well no 2 was dead but no3 had a very weak signal), turned out the injector drivers had gone down so got the injector drive and trigger transistors replaced and it was all good again, I was lucky as a mate of a mate is a genius and sorted it for me

 

Have a level 6 ecu with chip in it, so I could try it I know it won't be right with the throttle sensor but it would at least see if the injector will pulse again

 

That's exactly what I did after spending almost 2 days diagnosing the fault trying a different loom, sensors etc thought to myself id try my spare L6 and it purred away on all 4

 

Well I'll be giving it a go on Monday and hopefully all the problems will disappear

 

Any joys?

 

No won't start at all on the l6 ecu, which is in strange as I used to run it in the car when I was waiting on a new l8 chip, did check voltages to map sensor and injectors and found everything OK, map voltage at the back of the brain was 5v and 1.5v at ignition on and it did alter as engine speed changed, gonna look a bit more today and swap around 2 injectors see if the problem moves

 

A possible culprit for the car not starting is the water temperature sensor that goes into the back of the head, it's a pig to get to but I had starting problems with my 4x4 Sapphire once and it was the wts that was gone/faulty

Also what does the car do when you are out driving it and it comes on boost? Have you got like a mis-fire problem and what is the rev counter doing when you are giving the car a bit of boost?

 

The water temp sensor is fine both connection wise and resistance wise, it doesn't go out of range anywhere, driving along before it dropped a cylinder it drove fine but occasionally it would start backfiring and until you switched it off and on again it wouldnt clear itself. As said the car starts with its own l8 ecu but won't on the l6 for some reason

 

The L8 ecu has quite a good limp home mode the L6 is thick as fook and has none
This may explain why the L8 runs the car and the L6 won't

 

Good point well iam at work now till next thurs so I'll not get near it till then, plenty of thinking time as to what is going wrong