Just like you i've got few of them already, this time it is Bringbackford who is contemplating the purchase
Totally agree, nothing beats torque + dongle, cheap fast handy and configurable
in the past i swore i will never again step on icarsoft, but recently got v2 at massive discount and to my dismay and contrary to i950 it works
Also have mongoose + ids, the king of diagnostics, brain**** and zero portability with exceptionally appealing interface, but it does all and reads all so definitely a keeper

 

You want to be sure it is a pump before embarking on this adventure, that's why fuel pressure gauge should be on your list

 

Just got myself an iCarPro 4.0 BT. They say the poor goes two times to the store, we'll see.

 

No worries, it should work a charm

 

Hi,

Today I took some OBD measurements. These are done with an IcarPro 4.0 Bluetooth and OBD Fusion (Torque is not supported on my Android, go figure).

The measurements have been done after a hard reset, as I was initially working on the aerial and disconnected battery. After hard reset done, I took it for a drive, some city and some highway and some joining the highway. Now I can put my finger a little bit better on the situation: it is not solely related to the engine rev but to the position of the gas pedal. Reaching high revs in 2nd, 3rd at mid throttle or so will not give any strange behavior, but reaching around 4k at any gear at full throttle will. I can't say if the issue is improving or getting worst, I have get a little bit used and is not so scary as at the beginning (in fact it is not very scary) but it is also not something I want to put the car through often.

Anyway, back at the garage I put the OBD and took measurements at idle and at 2000 rpm, here are the data....The third picture was my first measurement, before the hard reset..I was a bit lost, I think I took it with engine off (but hot).

Fuel trims are ok right (below 10% offset)?

I'll update the OP as well.

Thanks.


At idle

At 2000 rpm

Before hard reset

 

My guess would be it is fuel starvation related. I have an XJR that behaved similarly when the second pump was not kicking in. Problems always occurred around 4000 rpm in any gear

Have you checked fuel pressure at the rail? Should be -45psi. Might be worth doing this when driving to see if the pressure drops off. This would indicate pump issues, maybe the filter on the pump is blocked or the pump is getting weak?

You could also remove the line from the pressure gauge and see if you get a strong steady flow of fuel with ignition on.

 

Thanks, how do I check fuel pressure while driving? I have bought a manometer but I had in mind doing it in static

Sorry but I do not understand the last sentence, what do you mean?

I can for sure check the pressure at the rail, and I still have a couple of bullets: the engine cleaner and cleaning the MAF...I hope it is not the pump, will hate to need to do that, I will need to contact a mechanic because I don't want to deal with the fuel lines.

 

Looks pretty normal at noted engine speeds, so: "Clean the MAF; clean the throttle body and plate; with ignition off move gas pedal back and forth to clean TPS; put a can of fuel system cleaner in gas tank (Gamout, Sea Foam, Lucas' best)," might also change the fuel filter.

 

Checking pressure while driving is a bit tricky, you would have to either pass the manometer to the cabin through bulkhead or hang it on the windscreen, for starters check the pressure at idle, at some middle rpm and at 4000rpm and see how it behaves.
Your trims looks good but you would have to observe them at the moment of engine malfunction to be sure

 

With regard to checking the fuel flow, when you connect the gauge to the schrader valve you can disconnect the gauge so you have an open tube to the valve. Put the tube in a bottle and turn on the ignition and see what the flow is like. I think the workshop manual has specifications for flow rate

 

I would again just change the pump? Your fighting a very old unit and it's pretty well worn out.

Here is where you can check fuel pressure on your engine. This is the injector setup from JPART.




Note the red circle as that is the Shrader valve on the fuel rail. As always these Jaguar factory diagrams are only somewhat useful.

Item #1 is NCA3027AF and it looks like this;





Yes the red circled item looks like a tire valve stem because it is! You remove the blue cap and attach a manual fuel pressure gauge. Note you will find this at the rear of the engine on the passenger side.

I did this on my old 4.2L SC engine in my 2005 S-Type R. You can borrow a fuel pressure gauge from an auto parts store that has the tool loaner program but I would just buy one to add to your tool collection. Around $50-$60. On the 4.2L V-8's Jaguar dropped this sensor in later years so you may or may have a test port.





OTC 5630 Fuel Pressure Tester

I like this one because of the extra clear hose so you can bleed the fuel off after you make your readings.

Since the test port on the engine is at the back on the passenger side I attached the gauge there and ran the rubber hose out the back of the hood and taped it to the windshield so I could read the mechanical gauge thru the windshield. I did this as I was not sure of the fuel pressure readings I was getting with my scanners. Plus the action of the needle on the gauge can tell you a lot more than some crappy digital readout.
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I'm not a happy flower these days.

Loaded Techron fuel cleaner and took the lady for a ride.

After 10 km ECL low coolant level intermittent.

Check the expansion tank back home, ring magnetic float seems to move free, tank not empty but also not very full. Small traces of a White residue at bottom of tank.

I called the guy who worked on the car after purchase, he confirms me he had emptied the circuit and refilled. He told me he did not see traces of oil.

No liquid puddle under the car, except one that was cold and look old maybe AC or go figure, looked like plain water.

So I need to refill and hope for the best. After the test ride I measured trims and they were very very low on the positive side at idle, but the stalling feeling was stil there, although I had the feeling that car runs smoother on city traffic, but I guess I need tot run more.

Mechanic recommended tot start with a compression test. I guess I can do this with the nanometer I bought?

Happy on the one side because I guess after all this I'll be more knowledgeable, which was one of the objectives when buying the car.

Finally, I saw there is a Self-Garage (service spots to work on your car with lift and assistance), but I'm afraid that changing the pump as a first timer is risky in terms of defining a schedule.

So, I'll refill coolant, do some more runs and report. Beginning March I have some free days, I guess I'll do the fuel/engine pressure tests.

 

Just fill the coolant and observe how long it takes to go low, the chance is that it will be in years range and nothing to worry about
Take car for a ride and try to get it to the point of hesitation while observing trims, it will be less burdensome than playing with compressions

 

Thanks xjack. My OBD takes around 60 Secs to create a report, I need to be 60 s in that situation? Complicated.

Maybe I can just run a fuel trim and drop any other reading? I'll check.


​​​​

 

Your reader should have live data monitoring, reports are nice if you want to analyze interplay of many inputs later on, but for purpose of this test have reader at hand and look up trims in the right moment

 

Just curious what spark plugs on the car ? Part number

 

I can ask my mechanic, I wouldn't know. But not the cheap type probably.

 

I refilled with coolant (around 0.4L) and the low coolant level light did not show again. I was hoping for it to reappear, I guess now I'll need to wait some weeks to see if it pops up again.

I took the oil dipstick out, no engine coolant in my opinion, just oil. At least I guess if there is a leak is not going to be the VERY expensive one.

I also did another drive, but since I'm an idiot, of course I only realized once back home that I could log second by second all the car variables and store it. Instead of that, I was just watching the live data as shown in the picture. The red line length in the left graph would be from the start of the X axis to the peak of the MAF in the right graph (that is what 2 university degrees look like gentlemen). Some things of interest in my opinion:

- Peak power is around 170 hp. The 3.2 engine delivered around 170 hp at 4000 rpm (where I hit the wall).
- The throttle position peaks at around 74% (shouldn't it be around 100% at WOT?).
- The short term trims go up and down but no crazy values I guess (13% on one bank as maximum and -11.72 on both banks as minimum).
- Max air flow around 140 g/s as you can see.

I don't know, I really have the feeling I hit an imposed limiter when I get to 4000 rpm...




-

 

You should be looking at long term fuel trims, at both banks and in moment when car stumbles.
Your short looks fine but they are not telling much
Yes your throttle should be very close to 100% at wot, so it is definitely a place to look, perhaps you have loose or badly adjusted throttle cable

 

MAF cleaner and Throttle body cleaner are on the way. I'll clean the TPS with contact cleaner. Will check the throttle cable.

Is it possible to check TPS voltage as I operate the throttle cable?