Hello,

Starting last fall I knocked out a BUNCH of projects on my 2002 XKR Convertible:
- Removed front subframe
- New motor mounts, v-mounts, subframe mounts
- Front ball joins
- Rear wheel bearings
- rethreaded rear half shafts to go back to OEM nuts (that one was fun to figure out!)
- Poly bushings on the front end and on rear sway bars
- Sway links all around
- Knock sensors (#2 was coding)
- Cleaned: Throttle body, egr, elbow, outside of supercharger

Reassembled and then No Start, No Codes. Identified that the fuel pump wasn't working. Then, when researching, found it has 2 and neither would come on when jumped.
So, we can add a pair of Duralast Fuel Pumps to the work list!

Now, both fuel pumps jump fine, jag tries to start but I get one rev then it dies. I get code P1671. When Jumped to pump #1 it revs then dies but the pump stay on (until I pull the jumper). When #2 is jumped it starts, and then revs to 3K repeatedly as the fuel gets forced through the rails. Up/down, up/down, etc... Again, until I pull the jumper then it dies. Each time the relay for the other pump was still in place.

In searching this Website I see that P1671 has switched a few times. So, from what I'm reading it could be Relay #2 fault, VVT Solenoid, the Cam Shaft Position Sensor, or an O2 sensor.

My Pump relays pass the 'click" test and have resistance of 95 ohms each when pulled. Pumps come on when Jumped, no other codes to indicate ECM.

So, I'm lost and need direction on what to check next. Anyone know (at least) what P1671 is supposed to mean on my 2002?

 

Is the 2002 from the VIN? I think you need to use the MY from the VIN and (hopefully) then the matching DTC (codes) PDF, usually available on JagRepair.com - Jaguar Repair Information Resource

 

VIN decoder verifies mine is a 2002.
Here's an interesting twist, the Jagrepair.com site does not have a MY 2002 Electrical guide. Has 2001 linked to MYs 2001 and 2002.
http://www.jagrepair.com/JaguarXK8El...OBDIIcodes.htm

 

HOPPS, check out the below link. It may provide what you need to solve the issue.

XKR and dreaded restricted performance | Jaguar Forum

 

Thank you Thermo. I appreciate the link. I read this one in my research. His issue was the pump wouldn't turn off but the car ran normal up to 3K due to restricted performance warning. My new pumps behave as expected. Pump primes the line when key is in position 2. Then starts, runs for 3 seconds then dies.

As I understand things, pump 2 does the priming then pump 1 takes over. Since the pumps are new, stay on when jumped, and relays test as OK, this seems like something else. Maybe with all the work I did under the "bonnet" I forgot to reconnect an electrical connection somewhere.

So, what electrical or mechanical issue would result in start then die BUT could be forced to run (albeit incorrectly) when pump 2 is jumped and vehicle started but not with pump 1 jumped? VVT, Cam Sensor, EVAP leak?

I've recheck all connections and can't locate anything disconnected. Corn-fusing!

 

I have the 2001 and 2003 editions of the DTC Summaries and P1671 is not listed in either one of them. The DTCs skip from P1658 to P1696. The 1999 Workshop Manual states that P1671 will cause limited engine speed/Restricted Performance, but does not offer a definition or possible causes of P1671.

However, the list of Ford DTCs revised in 2007 defines P1671 as "Secondary Fuel Pump Relay."

Have you tried swapping in a different relay? The Secondary Fuel Pump Relay receives battery power on the Brown/White wire at its socket terminal #3 from Fuse #20 (20A) in the trunk fuse box. Since you can force the pump to run by jumping the socket, that fuse must be good. With the key in the ON or RUN position, ignition-switched power should be present at the White/Green wire that connects to relay socket terminal #1. The White wire that connects to socket terminal #2 should be grounded via the ECM.

Do you have any other DTCs stored? Can your scan tool read Network (U-prefix) codes?

Cheers,

Don

 

P1671 indicates an error on the Fuel Pump 2 relay coil for the 2002 XKR.
Operation is per Don B's description - the ECM activates the relay by pulling the relay coil (pin 2) to ground using a power transistor (Q913) - the other side of the coil (pin 1) is connected to 12V supply.
The ECM also monitors the voltage on pin 2 (White wire) - if it does not measure 0V/Gnd when the ECM activates the transistor, or does not float to 12V when inactive, then the ECM will trigger P1671.

 

I did try swapping another relay into #2 (Horn I think) and got the same result when trying to start. I definitely hear Pump #2 prime the rails at at key position 2. It's almost like something is stopping the transition to Pump #1 to run. I did validate that the fuel shut off is not tripped.

I do not have a sophisticated ODBII scanner, but may be able to borrow one.

Considering all the other work I did, I think I need to go back through all the EVAP tube connections and maybe hit the MAF with some MAF cleaner (it sat on a shelf for 6 months exposed to debris).

 

Thought I'd close the loop on this one. Turns out the P1671 was simply caused by starting with the pump 2 relay pulled when I was investigating. So, still had a start then stall situation with no real codes to go by. So, I started from the top down, after removing the throttle body and testing all connections for continuity (all checked out) I started looking into connections just beneath. Eventually, found that the brake booster connection in the intake elbow was quite loose and the plastic push lock thingy was essentially disintegrated. Ordered a new connection and only used the gasket and push connect (brass fitting was OK). That was enough of a vacuum leak to cause the no start.

After reassembly, viola! Started right up, ran rough for 30 seconds as it figured things out. Now, runs smooth and no codes. I'm back on the road.

Hope this helps someone in the future.

 

Many thanks for reporting back!
Very good troubleshooting to find and repair it cheaply.
Good job!
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