Hi all,

I've just bought a Daimler Super V8 (MY 2000) 135k miles which has a few issues. From its history it appears it's been in storage for the last 10 years with an average of <50 miles per year. I've lurked on these forums and the threads have helped me solve the "Low Coolant" error by freeing the float in the header tank. With thanks to other threads I've also just replaced the ignition coil on cylinder 3 and cleaned the throttle body which has solved the rough idle and the misfire on that cylinder.

The issue I haven't yet been able to solve is the car being in "Restricted Performance" mode and the P1671 code coming up on my ELM scanner. My first port of call was the luggage compartment fusebox where Fuse 15 (20A) "Fuel pump (supercharger where fitted)" had blown. I optimistically thought this would be the end of it. Replaced the fuse, cleared the codes, and started the car and drove it around a bit. No dice. Still in Restricted Performance and P1671 code has returned as "pending."

I then took a look at the relays in the luggage fuse box. Fuel pump relay 2 has a red wire that connects to one of the pins for some reason. I took the relay out and put a spare one in. Car turned over but wouldn't start (presumably no fuel being pumped.) Replaced it back with the original relay (still with this red wire attached) and the car starts and runs (albeit in restricted performance.) I take it this is not usual? Potentially a bodged repair?

I will take some photos tomorrow in case that is useful but grateful for any thoughts on how I can get it out of Restricted Performance.

 

Hi Senex,

Welcome to the Jaguar Forums! It' great to have you with us.

Your extra wire at the Fuel Pump 2 relay certainly seems like a clue. Perhaps there was a short in the harness and that red wire was added to restore the circuit, but is now shorting itself?

Here are the Jaguar definition and possible causes of P1671:




If you can determine which pin of the relay the red wire is attached to, that may tell you what part of the circuit has a fault. You can download the wiring diagrams here:

Jaguar X308 Electrical Guide 2000

Please visit the New Member Area - Intro a MUST and post an introduction so we can give you a proper welcome.

Cheers,

Don

 

It appears that you problem is rather simple - your Pump 1 is dead and the additional wire is most probably there to "force" Pump 2 to run continuously from ignition n" to cover for the bad pump. Did you check whether the new fuse has blown again? If it is blown again, do not replace it again as the pump that it is for might be seized and shorting.

Instead, do the following test: remove the relay with the wire and insert again your spare relay. Switch the ignition "on" and just keep it there for some 45 sec to 1 min, then crank the engine. If it starts, it will confirm that Pump 1 is bad. In the case of failed Pump 1, what the ECU does is switch to Pump 2 (but it needs time to "realise" the issue, thus waiting 45 sec to 1 min is needed). With only one pump running, it will stay in "limp mode".

Otherwise, the two pumps operate as follows: at ignition "on", Pump 2 runs for a few sec. to prime the system; during cranking and later engine running, Pump 1 will continuously provide fuel and Pump 2 will come on only at times of higher fuel demands (harder acceleration or at high highway speeds).

So, it looks like you are in for fuel pump replacement. Of course, replace both.

 

they did all that just to cover up the RP message?