When the fuel pump cavitation issue occurs, at least in my case, the car will simply stall at road speed and will not restart until a cool down or some cooler fuel is dumped into the tank. That will get you going again. In my case it is either an on or off situation, there is no slightly diminished performance. Insulation on the fuel rail is part of the solution but I believe the heating of the fuel and “vapor lock” is primarily due to excessive heat in the vicinity of the fuel pump and lines which are relatively close to multiple exhaust components downstream of the very hot catalyst. It usually occurred after multiple hours of driving and is exacerbated by a tank that is only 1/3rd full or less.
yes mine was the similar before the insulation - it would hesitate sometimes stall but then did always restart at least. Adding fuel did help as you say.
for my hot start it cranks for ages - if i short crank than try again it always starts quicker
This symptom is often the result of a leaking back fuel pressure regulator that drops the retained fuel pressure in the fuel rail. Each time you turn ignition off and re-crank the fuel pump is briefly energized and it rebuilds pressure in the fuel rail. This situation is more likely dependent on how long the engine has been shut down, not so much a hot or cold start situation.
Hi John
That’s what I was hoping was happening but my car starts fine when cold regardless of how long it’s stood. I replaced the regulator last week with a new one. And no change with the hot start.
I’m out of ideas - it’s so odd that if you do a short crank stop then crank again it fires much quicker. Sometimes when cranking you can’t hear it has fired but when you stop cranking it sometimes actually starts.
This can be sign that the battery is weak. When the engine is still rotating and the starter is not drawing current more can go to ignition.
It’s a long shot, but you said you’re out of ideas.
Good luck, Alan
Hi Alan
The battery is new. It’s hard to describe but sometimes just as you give up cranking the engine starts running - like at 300 rpm then comes to life.
I’m out of ideas for sure.
I think I would rig up a gauge on the fuel rail and monitor pressures as this occurs.
Sorry that’s a blind alley for you.
Sounds like a good idea. I’ll try that