hunting 92 spi

[MiniHaven]

got an spi in at the mo has good tick-over and revs up to three thousand and then above starts hunting as if you had your foot up and down on the throttle . any ideas chaps , we've looked at the fuel supply and return fine , put the diagnostic machine on it , no faults reported by mems ecu , checked the dissy and coil all ok , checked the maps tubing for obstruction fluid or otherwise nothing , suspect fuel pressure reg in the injector body ,,,,,,,,,, but not sure especially at 329 quid each !!. were a bit stumped ?.

[vanman262s]

sounds like a air leak around the manifold

[Simon1275mpi]

Hi,

Check under the air filter box. The vacuum pipes off the manifold. The manifold pressure sensor or even the good old carbs will not hold a rpm with a vac leak.

Rubber pipes should be tight and it good condition. Best off secured with clips.

Si

[Simon1275mpi]

Bugger - Start writing a reply, get dragged away from the box to eat, come back and finish up. But some nice guy beats me to it!!

[monkeyjim]

Throttle position sensor
D

[annon]

doe's it burn a lot of fuel?

[MiniHaven]

tried pipework for leaks ,no leaks . manifold seems ok no induction leaks , not sure weather it burn a lot of juice , plugs are not sooted tho. throttle pos pot cheaks out ok ,also idle switch cheaks out ok .
after spending many hours on it we finally gave it back today stumped , customer was happy we had tried we suspect a faulty fuel reg in the injector body however will prob never know now thanks for all ur words of encouragement
regards

[minimole]

got the same kind of problem with my carb'd mini atm i have stripped it down as i wanted to clean it anyway, but i suspect it is that the manifolds are not lined up properly. it is possable to mount the inlet manifold "low" due to the way they are fitted. i would have a look at that. hope it helps