Quote:

What pin is the ground pin for the ECU?

Pins 5, 16, 17, 35

Also, all the fuel injection ground wires are attached to to the rear of the water rail. Worth checking this ground point

Cheers
DD

 

Thanks Doug! I didnt know it was there. Its similar to the check valve in most Euro cars of the time. My 911SC and Volvo had the same type of check valve. So if the OP is able to order a new OEM one he could just drop a new one in or technically install the new one in place of the old one.

 

Haven't checked recently but I'm pretty sure the original valve is NLA from Jaguar

Cheers
DD

 

Im sure you’re correct in that the OEM version is NLA. So I’d just install the modern racing FCV in place of the old one or place it closer to the fuel rail. Mine failed on the XJ40 and Getting to it meant replacing the pump, so I installed one in the engine bay, where its been for almost 7 years.

 

yes thank you Doug. I was unaware of this check valve until today. CAC2027

​So the Ford boys were correct after all !!

this valve sure isn't mentioned anywhere.

 

im amazed! You know these cars in and out too!

 

Just wanted to update this thread as I had time to give the added check valve a try. I could not install it in the engine compartment as a mechanic had previously recommended and installed an additional fuel filter near the fuel rail which would have made it a tight fit up front.

Extra fuel filter at fuel rail

So, instead I put it just after the factory fuel filter at the back of the vehicle as shown below.



Additional fuel check valve

I also replaced all the original fuel hoses at the back while I was there as they were showing signs of cracking with age. While everything worked fine, unfortunately this addition did not make any noticeable improvement in the extended cranking to start the engine.

It is almost as if the ignition or the injectors take a while to get working. I have never looked at the grounding points on the car. I am sure there could be issues there.

Is there a good reference for where to find all the grounding points on a Series III and what (if any) improvements to make in the wiring to ensure proper grounding is available to all components at all times?

The car continues to run and drive very well. Starting (warm or cold) is still the main issue.

 

at the rear top corner of the cylinder head, intake side, there is a bundle of ground wires connected with a bolt to the cylinder head. Those are the fuel injection grounds.
Remove the bolt and clean each ring terminal shiny, including the ground strap in that bundle.

 

Sounds like a good starting point. Where is the ground for the ECU that controls the fuel injection system?

 

The entire fuel injection system grounds at that point.

See post #21 above 👍

Cheers
DD

 

Got it. So pins 5, 16, 17, 35 are also worth a look. I'll give this all a try as soon as i can find my multimeter and get a jumper long enough to reach back to the ground post on the battery.

If I find one of the 4 ECU pins floating, is the best fix to run a new wire back to the negative post of the battery and connect it right at the ECU main connector?