Fuel Pump Current Ramp Waveform - bad pump?

Hello,

Background Info
- 1995 Jaguar XJS convertible 4.0L inline 6
- 2 issues:
a) upon initial start up, engine runs smooth for about 15 seconds and then runs rough. Have an EGR code (don't remember the code at the time of writing this post), but likely this is reason for rough idle
b) looses power when at WOT

Please see attached pic of current ramping the fuel pump
- I zoomed the picture out 8x in an effort to establish a pattern
- I've establish the following from the attached pic
- pump has 8 commutators
- highest amperage reading is 6.1 amps and lowest is 4.7 amps
- based on cursor 1 and cursor 2 positions, 1 full revolution of the pump is 9.5 ms
- pump's speed = 60,000 / 9.5ms = 6,316 rpm

My thoughts on the health of the pump
- pump is okay (not great) because it has a decent speed (i.e. 6,316 rpm), however, I think the pump is starting to fail because of the uneven hills (not all hills reach 6.1 amps) and valleys (not all valleys reach the low of 4.7 amps).

Today's $2.00 question - can I determine that my WOT problem is from the pump based on this waveform? Or, do I need to get into the trenches and test fuel pressure at idle and WOT with a gauge. (FYI - Jaguar in all of their wisdom / trying to force people to take it to a Jaguar dealer, did not design this fuel system with a schrader test port)?

As always - thoughts appreciated and thank in advance

Jaguar XKS ---- not worked on a 99 MY USA model but Jaguar usually put the fuel filter in a really accesible place in the spare wheel well easy enough to either T in or measure the dead head pressure.

95 might make it hard, but if you have scan data you can watch the o2s during a wide open throttle pull.
If the pump is healthy enough, the o2s should report rich @ wot.

To answer your $2.00 question.

IMO, the amperage of the pump is low.

But use your Load PIDS from scan data to give you direction first.

On a WOT run, if your Absolute Load and Calculated Load are high, and you have Fuel TRIM (POS in your case I would think), you've got a fuel delivery issue.

IF the Load Pids are low, coupled with Fuel trim your looking at an air issue.

A good engine has High Load pids and no trim at all operating ranges of the engine.

Low Load and NO TRIM, the engine truly has a pumping problem

Weycraze wrote: IMO, the amperage of the pump is low.

RPM also looks high. Might be normal for that pump or could be due to low pressure. Would be interesting to dead head the pump and see if that changed amps or RPM.

Agreed scan data would be the better way to go if it's available.

Hi everyone.

Lack of power could be also related to EGR leakage.

EGR valve is suppose to be closed at idle (to keep a smooth one) and at wot (to not reduce total power).