Hi Guys,
Can somebody tell me how to disconnect this connector ?


This is the fuel pressure sensor. I'm getting a P0193 code pretty consistently. I've changed the fuel filter recently, run some Techron through it and I always use premium gas with detergents in it - so I'm thinking this sensor may be the culprit. As with most jobs, for me anyway, the connectors are the hardest part. Of course it is old plastic and I'd rather not force it and break whatever holds the thing on. I tried squeezing at the bottom with no luck. There is a rectangular opening in the top, maybe that is the trick ? TIA.

 

I have replaced this sensor before, and the connector did not fight me back. 10 min job (my sensor was leaking gas).

FWIW, you might want to log some ODBII data for fuel pressure and manifold pressure. There is a post from a long while back that details some of this. The idea is that the fuel pump controller build pressure through PWM on the pump, based on the input of the fuel pressure sensor (there is no return of gas through a regulator like in the older systems). The sensor has a reference to the manifold pressure (that vacuum line). So, all the controller needs to do is control the width of the pulse on the pump for pressure. The complication is that if you suddenly drop manifold pressure (close the throttle), then there is sudden excess pressure that needs to drop. From what I gather, this is done through a pop valve in the tank, part of that expen$ive assembly. If the pressure is somehow not dropped, the sensor maxes out and you get P0193. By logging fuel/manifold pressures, you might be able to see if the code comes up under deceleration. Pressure should be very near 55 psi, and should no deviate more than, say, 1 psi each way. In other words, I am not sure throwing a new sensor will help (not super cheap), and unfortunately that valve in the tank might be the problem.

Best of luck, keep us posted.

PS: Old discussion (no resolution) here: tricky-problem-fuel-pressure-too-high-p0193

 

Thanks much Fred. I have been scouring the threads and saw many of your posts, and really appreciate the advice. On the connector,
I found a video - of course. The guy just squeezes it at the bottom and it comes right off. I guess I'm just getting feeble !

 

You should just need to push on the tab and pull strait up.

Might be full of dirt and stuck though, you can use a small screwdriver between the sensor and connector to gently pry while you have the tab pushed in and released.

 

Thanks Charlie. I'm an expert now. I was pushing on the bar at the bottom (too low). It's always the little things.

 

I thought I should report back on the P0193 I was getting. I hooked up my UltraGauge (OBDII reader) and set it to display fuel pressure and the 4 fuel trims and drove the car for a couple of days like that. The fuel pressure would usually stay around 54 - 56 PSI, but at times it would spike to 70 and drop to 35 or so, and when this happened I could feel the car surging and eventually it would throw the P0193 again. So, not wanting to think about pulling the tank and putting in a new fuel pump, I ordered a new fuel pressure regulator. It was a Eurospare for about $50. This did the trick. Now fuel pressure stays between ~54 - ~56, and usually around 55.

Not a real good photo, but it reads 55.3 for fuel pressure. The others are fuel trims. Of course the obligatory mask !

 

Have replaced this sensor myself (with the help of Fred Mertz). As I remember, I was getting a pulsating feel driving at a steady at say 60 mph. Soon after I got a check engine light and a code (?). Think I got my sensor from Rockauto $50. Easy to change and the problem was resolved. Good luck.

 

You own a Jaguar...there are no stupid questions in regards to these cars...