Sorry,,, I can't multi quote on my phone, lol... I'm in a proverbial SEA of technical difficulty these days, lolololololololol

Yes, the language is technical - and that's what I meant. Some voltage value (I'm thinking) higher than the 3.xx varying up to some higher value. FPM sensing and responding to 10ths of a voltage but from say 5v,,,, up 8 or 9 ~~~ maybe... I don't think my 3.73 volts meets that lower threshold. Which sucks. BUT,,,, I don't think I'm getting and average, here. I think it's a steady,,, although faulty,,,, voltage. And it's with this voltage the FPM would translate INTO a pulse on the ground side. Again,,, I could be wrong. I don't know how the FPM translates a positive ECM voltage... Or,,, what that voltage would need to be.

I meant what is preventing the ECM from providing the FPM a varying signal it can use and read LIKE the rail sensor is sending it's varying signal to the ECM...

​​​​I need to get back to this machine... Having theories with out being able to test them is making me craZy, lol... All like I'm groping around in the dark...

Saturday.

 

I hate the price,,, but if push comes to shove..

https://www.milspecwiring.com/DUAL-H...DGE_p_749.html

 

That just isn't the way it is designed to work. Sketchy as the available information is, there is sufficient out there to determine how the fuelling system has been implemented. We have to take Jaguar's word on this.


The way the engineer designed it. In practice, it is doing just that, albeit in a different way. ECM <-> FPM is digital PWM (varying duty cycle), fuel pressure sensor -> ECM is a varying DC voltage.

One key advantage of PWM control is efficiency, although we're likely straying too deep into the theoretical here.

 

I agree about not going tooooo deeply into the theoretical. I like to have a little better than a general idea about how something (things) works, but usually, don't want or need to go in much further than that. I usually resist that and dont want to go there, depending on what it is. Really,,, I'm not studying to be an engineer here, lol

But, lol, I have been reading some, watching some doggone YouTube videos - and stuff... What I came away with was (and hell yeah I could be wrong) that the duty cycle between the pump and the fuel pump module is the only thing working on a duty cycle and PWM. That the signal sent from the fuel rail pressure sensor to the ECU/M is a simple but varying voltage. That from there the signal from the ECU/M to the Fuel Pump Module is a simple varying voltage (pin 3) - Essentially a ECU/M translated measure of that pressure sent to the FPModule in simple volts... That the fuel pump module then takes that simple varying voltage from the ECU/M and uses it to control/determine/create the rate of pulse, thus creating the (varying) duty cycle with the pump... Is that right? Again, this is new to me, and i am ok with being wrong...

That also,,, the FPModule also creates a wave of sorts,,, information it sends back to the ECU/M (pin 4 - unreadable in my testing/probing) letting the ECU/M know everything is oky doky or if there is a problem...

​​​​​​Please know that I am not challenging you,,,, just trying to understand....

 

No. according to the 'documentation', the communication both ways between ECM and FPM is via a PCM signal

Yes. Higher the pressure, higher the voltage & vice versa.

No - it's the 150Hz PWM signal (see the pdf)

Not quite, as per above. The FPM takes the PWM signal from the ECM and outputs its own PWM signal to the pump.

Yes - it's the 1Hz FPM signal (see pdf), your fluctuating value on BT18-4

Not at all:- please do. It's sanity checking at the end of the day and - perish the thought - I can be wrong.

When the fuel pump on the MGB used to play up I'd get the rubber hammer out of the boot. Didn't need any new-fangled oscilloscope for that

 

Hey All...

First thing I need to do is thank folks who have taken this ride with me... I really hope I haven't wasted everyone's time just because I'm trying to save a buck or two, anywhere I can.

As of now, problem is not solved, per se... I do have a running pump but it is not as designed,,, and I'm not really sure what to do - other than go out and get another new pump...

I tested a new Walbro pump this weekend. Rigged two long wires tapping into the R and YR wire on the FPM side of the connector, disconnecting the connector. I took the pump around to the driver's door and held it in my hand as I turned the key... At position 2,,, the pump would kick in my hand for a 2 count. Then I could feel it relax... Never full turning. Then, as I went into the spring in the ignition for START, releasing the key (the car would run a little on the residual rail pressure for a bit, I could feel the pump in my hand kick again, never spinning.

​​​​​​If I used the jimmied set up and ground the new pump it would spin like no bodies business...

This is leading me to believe that trying to run a NON PWM pump is my problem,,, because I'm cheap... I am thinking I will ship this pump back,,, take the return, add 100 bucks and get the pump Walbro says is "designed" for PWM set up... This pump, Walbro told me wouldn't "benefit" from the PWM set up. Which left me holding onto a false dream...

I feel bad and hope folks don't get too frustrated with me or feel that I wasted your time...

Definitely to be continued. I need the PWM set up working correctly... And will get it.

We shall see.
​​​

 

Yes, that seems quite likely.

 

Jay, we're with you. Sounds like you see the light at the end of the tunnel with your latest finding.

John

 

Other Forum members, like GD, had to pay the big bucks for the PWM pumps for the later X100 models. Can't see a way around it from where you currently are.

I'm also a penny pincher miser when it comes to car parts, and often you can find more modern, better and cheaper parts from reputable manufacturers, rather than pay for the eye-watering expensive OEM original parts. However in the case of a fuel pump, it's essential for the proper running of the car, so maybe it comes under the category "You just have to pay for the OEM."

Good luck and keep at it. You're almost there.

PS After all your efforts, is this now your car?

 

Thanks guys...

Is it possible to GET the VDO pump that comes in the basket,,, without the entire basket? It's $6 dollars worth of plactic,,, not $600.

I get this from Walbro ~~~~ """The Tia485 and Tia450 are both PWM compatible and can also be used with E85 if you choose. They have a 450LPH flow rate."""" $150 bucks or there around...

The first time, via email, the rep told me that the 455LPH pump would work but not "benefit" from a PWM signal and that PWM would shorten the pumps life would be short... Anywho...

I appreciate y'all (especially you, Michael) for sticking with me, the penny pincher, thru this....

Still,,, I literally don't have the cash for a $700 fix, plus other things on 3 other cars, so I have to figure it out...

 

So, progress. It seems that the ECM/FPM combo is doing what it should - or having a good stab at it. Initial burst at switch-on, then on fire-up the ECM eventually gives up trying either (possibly) because the fuel pressure isn't rising on command or the FPM is telling it directly that there's a pump problem (via the heartbeat).

Please don't spend any more $$$ on something that 'might' work, or 'might be designed to work'. I wonder what's special about the OEM pump other than the price - do you still have the original?

 

Hi! Thank you, Michael... Seems like progress...

Foolish me,,, the old pump (VDO) was badly stuck, gummed up... I shouldn't have but after soaking it (fort days) and shocking it, it not moving, I cut it open to see what made it tick. Then, free'd it (of course), then tossed the remains... I've been kicking myself since.

If anyone out there knows which VDO pump comes in the full fuel pump assembly, I'll try to track it down individually. I CANNOT pay $700 bucks for a new bucket and pump (really really don't want to)... If I can't find the VDO I will try the Walbro pump THEY say fits,,, and if it doesn't I'll return it and start squirreling pennies for the real deal...

I hate the idea of running a pump and driving (in the future) on the jimmied direct ground pump...

I also hate the $700 game suppliers are playing with fuel pumps... But that's a whole other story.

Working on seats today. Wish me luck!

 

This is a long shot - you likely have checked this so apologies if I've missed it.
Is the FPM ground definitely good? You can check with your meter between pin BT18-6 and a known-good ground - or simply jump the pin to same ground

If you see any voltage or fluctuations at all when the pump (any pump) is trying to fire, then there's a grounding problem.

 

Good luck. If it's the module(s), extra special good luck.

In any case, looks like someone on ebay has been rooting through your trash...
https://www.ebay.com/itm/JAGUAR-OEM-...gAAOSwxbxcyOMr

 

HOLY ****!!!!
BOUGHT!!!

That is a big big deal, Bass! Thank you so so so much...

I have two xkr seats from a coup... Working on them. I'll have questions and will post a new thread.

For now, on the driver's side, everything seems to function except (of course) the forward and backwards. Can't bolt them in... It will start to go, then stop... It's like maybe something is out of line... Then I'm seeing something that looks like a sensor? NO seats in this thing when it was,,, aquiered,,, really the only thing completely missing from the outset... I still need the luck O the Irish here.

Then, roof. The menace who basically gave me this thing went to town on it. Just got a handful of new pins and clips from McMaster... Two bent hinge arms... Need a pump motor. The fluid section valves and such are (seem) ok. I think I posted a picture. The motor was mud filled.

So it goes, lol

I'm having fun, though!

 

You know what, Brother... I don't know how well I had and did... But good point, worth doing again,,, GREAT ADVICE,,, and I'm all over that...

Bass just pointed me to a great pump deal,,, if it is, lol...

And,,, the downpipes for my XJS got in today.

And,,, got my teeth cleaned, lolololololololol

"It's a beautiful day in the neighborhood..."
(If you don't know that quote ^^^^^^ above, Michael) Google it, lol

 

Happy to help, happened on that 'pump' (or bits of pump/pump module) in my frequent searches for yet another cheap piece to replace broken plastic.

On forward/backwards, you may be able to check the motor easily by powering it with a battery. Depending on what seat you have (classic?), fore/aft connector may be right on the front, first thing you see, four pin connector, two leads, switch polarity to move in each direction. Seems like that was by design since it would be difficult to remove the seat without fore/aft travel.

 

Did someone say,,,, plastic? What do ya need? Seriously. I have lots of stuff laying around here...

What I found at the front of the underseat framing is a small black box with heavier maybe 12guage wire, interesting little cris cross thing inside with a coil of some sorts... The seats are out of the car (not original seats) and the motor will attempt to move. Threading maybe a half inch forward,,, half inch back. It seems to be at the end of its travel,,,, seat moved forwards. I think on the weekend I will unmount the upper padded section and work on the base. Very cumbersome working on the seat with the top attached. Anyways,,,

So has it, the guy with the pump has other parts, XK. I messaged him and explained the mountain I am climbing with my Olympic Swim Team XKR... He texted that he had some experience with where I'm at (go figure) and invited a phone call. Ya can't make this isht up, lol

I am very very hopeful about the pump, Bass. Couldn't have expected anything as fortunate happening. Now, we'll see if,,,, well, we'll see...

Have a great day, Y'all!

 

Completely Frustrated...

So, the OE pump and bits came in the mail last night. Went to try it out today, rough weather and all. Noooo Joy... I am out of my depth with this one...

Connected, the pump,,, ran outside of the tank with jimmied ground... Not, with OE ground. Yeah, feeling a bit defeated here. Say I were to work with an osilloscope, find that there was a problem... I would know what to do then? It's a pain. 70.1psi with jimmied ground. Should I just count my blessings and forget it?
​​​​​​

 

ADD...
I should add that the OEtype VDO pump clicks and jumps thru key turns,,, damnedest thing. I hate electrical issues.