The car runs fine. Doesn't stumble or anything when you floor it. Floor it, and it'll spin the tires easily. No codes are being thrown or stored. But when I watch my AFR at WOT, it's at 14.x
I've seen people on here say it should be 10-11 AFR at WOT. I want to do upgrades to the R this spring. But want to get this issue resolved first.
In the summer of 2020, I installed new:
Fuel pumps(Delphi brand)
Mann Fuel Filter
OEM Mass Air Flow
And new MAF connector(November 2020) which fixed erratic MAF readings.
Speaking of the MAF, I have questions. I believe a stock R should show a max reading of 289 g/s at WOT. Now, should you see 289 g/s anytime you go wide open throttle? Or should 289 g/s be shown when you're flooring it at a certain speed? I do want to buy a smoke machine to test for vacuum leaks. Anyone have any suggestions on what smoke machine to buy?

Oddly, I was scanning another 02 xjr. It also showed a 14.x at wide open throttle. But ran strong and fine otherwise.

 

Sounds like your car is running fine ever since you fixed the MAF connector. I never have checked the AFR on mine, just relied on the fuel trims. For the MAF readings, I'll have to hook up my big scanner and take the car for a little drive, which I haven't done since finishing 'the project from hell.' I did some "mods" to the intake elbow while it was off; put a -4AN fitting with a 5/16" hose barb for the brake booster tube, and made a connection from spare hose to hook up the part breather. Of course, the outer ring on the Norma fitting for that thing broke, and I didn't feel like buying and fitting that whole piece when everything else was fine with it. It seemed like the MAP reading was a little higher when scrolling through the live data on my little scanner. I was more interested in seeing the fuel trims after having the injectors cleaned and flow tested and putting on the new downpipes and O2 sensors. So far so good in that department. I'll try to do a 'live data' run this afternoon and take a piece of paper and a pen to write down the numbers.

How did you make out during the **** storm last week?

 

Nice to hear your fuel trims are fine after the injector cleaning. It was a **** show 2 weeks ago. Stayed home from Sunday-Friday. Roads were not drivable for me. Otherwise, I was fine.

I did monitor my short term, long term fuel trims and air fuel ratio while driving it, earlier today. Fuel trims are fine, unless you floor it. Then it's too lean. Otherwise, perfect numbers at idle and cruise.

Throttle position reads 100% when you are at foot to the floor. Got it up to 5,200 rpm and it wasn't lacking in acceleration at all. Where of course, it was lean. Haven't taken it to redline in quite some time. Because I'm not looking to kill a piston.

 

Without having to look in your old threads related to this issue...

Have you tried running a can (or 2) of pressurized fuel injector cleaner? Just an FYI, don’t get the pressurized efi cans from Napa! Get them from the Toyota dealer.

 

Never heard of that. But I'll look into it! Old thread was about running rich at odd times. Which the MAF connector fixed.

 

My last wasn't supercharged, but it was flat at WOT until I cleaned the throttle plate and bore. Might also look to leakage in the air piping.

 

What do you mean by flat? Down on power?

 

Took mine out for a run and the only thing I noticed was the MAP was up to around 16 In/HG at around 2200 rpm. But, I was on a two-lane road so not many opportunities to look at the readings while I was driving. I'm going to have to read the manual (again) for my Autel scanner to get to some sub-menus and record a couple of acceleration runs. One problem that I'm having is a a couple of DTCs; P0460 which is a short in the fuel gauge wiring and P1649, a flash memory something that I'll have to do some reading on to decipher the acronyms. Kind of interesting that I get a CEL for the fuel gauge.

Glad that you made it through the **** storm without problems. My son lives on the other side of the Metroplex in Justin. His pool equipment got trashed, but no other damage.

 

I was also blessed to have electricity the whole time. Sucks about your son's pool equipment, but coulda been worse. Hope you get your codes sorted. If I can't figure my issue, I'm going to talk to a few Euro shops. Take it to whoever I like best. Sucks, but I may have to swallow my pride.

 

So, I took my car to a local Indy Euro shop. Told them my car's AFR goes lean at WOT. No codes. Said they'd look at it. Great. Called me 2 days later. Long story short: I was told, "Cars should run leat at wide open throttle." LOL. If you are a local Dallas person, and want to know what shop this is, just send me a PM. They didn't charge me anything. So there's a positive note.

That said, I'm really dumb founded by this. Car pulls amazing. I'm going to buy a long fuel pressure gauge. To see what happens under load. Desperate at this point. I have been saving my money to mod, improve some cosmetic issues and sound system. But this lean issue is holding me back from doing so.

 

If I were you, I’d PM Avos. He’s extremely knowledgeable about modifying the supercharged cars and AFR’s will be right up his alley. Mind you, he’s in the XKR forum mostly but still the AJ variant engines.

 

I let off at 5,500 RPM. Wot fuel pressure is 54psi. That seem correct?
Also, ran a vacuum leak test with a smoke machine. No leaks.

 

Saw your private mail, and will respond here.

WOT fuel pressure is perfect!

Am not a fan of standard odbii derives, its already hard enough to get good granular data via the IDS, so I am not taking what you read as trustworthy.

If it was really this lean you would notice misfires as well, do you experience any of that (don't do to many runs if you don't trust your car though!)

So if you're not able to use the Jaguar tools (ie the IDS) to get some proper measurements, then I would advise to have your O2 externally measured, for instance on a dyno. That will also give you an idea if the power is where it should be (give or take).

 

Thanks for the response, Avos!
I don't get any misfires at all. Whether at idle, cruise, or WOT. And when I let off the throttle, my obd2 scan tool goes rich. Like 11-12 AFR. I hope the car isn't actually lean at WOT, like the obd2 data says. Everything else in the obd2 data seems to read correct. Example, rpm agrees with what my tach says. Fans come on at 205°F and turn off at 194°F.

 

If any of you guys have obd2 scan tools, can you guys check what your supercharged x308's are reading at wide open throttle? Supposedly, the afr reading is based on our wideband sensors. I would assume if I had bad widebands, it would throw a code. When the afr goes lean, both banks show the exact same fuel trims. If all else fails, or I can't fimd anything, then yes, I'll get it on a dyno.

 

I think that OBD lean/rich values are not required to be reported at WOT so don't look at them. If you really want to know, use a wideband sensor and measure it directly.

 

 

That's just showing off

I thought our upstream o2 "sensors" are actually widebands, from factory? I believe from 99 and up, they are widebands. Which is why it doesn't show o2 sensor readings in voltage.

16.64 AFR was when my throttle angle was at 100%

 

Because upstreams are wideband you should look for downstream voltage at WOT. Should be around 0.8-0.9V.

 

Using the same obd2 app(Dash Command, not the free one) I scanned another 02 xjr at WOT. Surprise, surprise, it also reads a lean AFR at wot. This car also runs fine and makes good power at wot. So that is three 02 xjr's I have scanned at wot, and show the same lean afr. That is odd. Just thought I'd put it out there.