3.5 EFi - some sort of electrical problem

Any coolant loss? I was losing coolant from my '88 3.5 V8i with no signs of leaks. My 'man wot does' told me that a symptom of head gasket problems manifests itself as poor starting from cold, as if you have lost one or both of the rear cylinders. This is because the head gaskets can leak coolant around either of the rear cylinders on each bank into the cylinders as the engine cools - i.e. the vacuum formed as the engine cools sucks coolant into the cylinder. At cold the water in the cylinder causes poor running until it's been expelled.

I didn't have the poor running symptoms but since the head gaskets have been replaced I don't have the internal coolant loss.

HTH Richard

Hi Richard

Head gaskets were just done on this one - leaked between 2 & 4 cylinders and steamed like The Titanic. That's all done and dusted but I am left with the current puzzle.

Graeme

Ok, I take it it only does it first start of the day? There are 2 sensors at the front right (facing engine bay) of the inlet manifold. One is the temp signal to the ECU, the other is the Thermo-time Switch. This switch controls the ammount of extra fuel added by the cold start injector on the left of the inlet plenum chamber. The rough running just after startup is almost definitely due to excess fuel from the cold start injector. You can try replacing the switch (not all that cheap), or try simply unplugging the cold start injector. If it still starts ok, leave it disconnected. If it still runs rough, replace the injector as it's probably leaking fuel in when it shouldn't. Good luck. Badger.