Rusty my well traveled x300 has developed a fault during her winter rest. Was perfect when parked up three months ago now won’t rev passed 1200rpm. Starts and idylls perfectly but as rev builds it’s like she floods herself with fuel. Any ideas appreciated, I’ve tried what I can think of.

 

Short term fuel trim as it climbs through revs . Target 0 %

The 1 fuse for all O2 sensors internal heaters to read correctly , either as only 1 # 10 , 12 , 14 , or 16 right engine bay fuse box

MAF connector still attached middle wire on paper 1.2 volts DC at proper idle speed this value climbs toward 5 on throttle up

TPS connector still attached 0.60 volts DC at the idle stop , climbing toward 5 on throttle up . No opens on this variable resistor as you very very slowly bring throttle up ( engine does not need to run )

This TPS connector hidden can be read as it passes over the fuel rail if you knick the wire or at the ECU connector as pin X and Y but reading the resistance value again . not seeing an open

 

I thought about it over a cup of tea. It had to be something affecting whole engine, not just one cylinder as if just one cylinder engine would still be able to rev. It was faulty when hot or cold, so couldn’t be O2 sensors as they are out the equation when cold. It wasn’t the MAF sensor as that was working. Only other thing could be crankshaft sensor! Took it out, replaced for a spare I have had for years and hay presto she was fixed

 

There has been recent talk on cheaper CKPSs even though is a generic part and not Jaguar specific

Someone found grime on the sensor face looking at the spinning target and one even had a extra ( now 2 instead of original 1 ) missing tooth broke off removing the harmonic balancer using alternate method ( jamming large screwdriver on existing teeth that need to stay to lock crankshaft / tooling of sorts )

Keep a spare jumper for the fuel pump relay as that single CKPS signal can fail in the fuel pump enable aspect

If I recall you had a CKPS wiring issue in the past

 

A silly little broken CKPS is not gonna keep Rusty down for long! Nice work, Stu, go for the #1 easy things first. I think I should drink more tea.