Hello everyone, i got problem with my jag. He still cant accelerate well, when i start accelerating, it starts to choke. I have no idea what to do, 0 error's. 0 comunicats. Well, all sparks, coils, intake gaskets, both catalyst, lamba sond's changed. Any idea's ? What can it be ?
when it warms up very much it's better, but still it dont accelerate well.
Strange thing is when i drive easly about 5 km and go full throttle it goes well, but when i slow and accelerate again it start to choke, i need to drive easly again few km and it goes a bit better.

Sorry for my english but im trying to describe best i can

 

What do the fuel trims indicate? Can you take a reading with a suitable diagnostic reader and then post them back here for the forum...?

 

I have just simply OBD Reader. What the fuel trims should like in good engine and on what RPM's. Or others parameters like fuel pressure, intake pressure, MAF , so i can compare to my . and i have too add that when car is working on idle, i can smoothly add gas to max , no choking, its only when im drive

 

I would suggest that you get a diagnostic reader that can get your long and short term fuel trims at idle and 2.0~2.5K RPM and post these values back here for our resident experts to have a look at. Fuel pressure at the rail should be 45-40 PSI, if I recall correctly. How recently has the fuel filter in the behind the left front wheel liner been changed?

 

So thats tej values on idle


nad Here are on 2.5k rpms


And here arę codes i get

 

Not properly warmed up (ECT quite low) but probably has no air leak so you may be looking at inadequate fuel flow (blocked filter, failing pump,...) or blocked cat.

 

I regenerate both cats, what about DTC' ? so i will replace fuel filter, - fuel pump is new. What i have to check ?

 

Your fuel pressure looks good, but a filter change is not a bad idea if you don't know the replacement history of this component.

You also have a couple of stored codes, an evap leak and one, P1245, for which two possible descriptions have been posted on-line; one fault description deals with an alternator issue and the other deals with a crank position sensor:

https://www.justanswer.com/jaguar/7v...tool-says.html

Perhaps one of our tech gurus can chime in on this...?

 

fuel filter changed, no diference, what's i have to search now ? what do next ?

 

Here’s the official Jaguar document for trouble codes:

http://jagrepair.com/images/AutoRepa..._OBD_II_R2.pdf


P0455 is for the evap monitor system, so I don’t think that’s the problem. P1000 is just the status of the readiness monitor, also not an issue.

I’d suggest concentrating on P1245, a fairly uncommon code. If I understand it correctly, it means the PCM is expecting to see a certain voltage from the starter relay when the starter is engaged. This is the signal so the PCM knows the engine is trying to start, and can schedule fuel and ignition accordingly.

I’m extrapolating here, but I don’t think a fault during the start cycle should necessarily affect how the engine runs once it does start. But it does make me think the battery voltage may be dropping too low under the load of the starter. That can cause all sorts of havoc. These cars are very sensitive to low prestart battery voltage.

For a quick test, hook up a automatic battery charger overnight. The next morning, disconnect the charger and then turn on the headlights for about 30 seconds to draw off any surface charge. A good battery should show at least 12.6 volts.

 

Also, check the alternator output. As smart as these cars can be, they are not programmed to warn you of decaying battery voltage until it’s WAY too late.

Right after start, a 2003+ car should show about 14.5 volts at the battery. After a few minutes, the voltage should decrease to approximately 13.5.

 

well, its about DTC's , fine. What about the main problem, that car cant drive properly ? I think it can be something with fuel/air ratio bc the engine is very hot, coolant is ok, but when i open the hood - hot air just blows and i cant hold for 2 seconds my hand on air intake

 

I'm just looking for little clues myself. I picked up on P1245 because it MIGHT indicate a low battery voltage problem, which in turn MIGHT cause poor running. It's quick and easy to rule out by fully charging the battery and taking a couple of voltage readings.

It's kind of like going to the doctor. Whether you've got a sore back or are coughing up blood, no matter the symptoms, they always check basics such as your temperature and blood pressure.

 

battery is new, im really sure she's good. it shows like u wrote, 14.4-14.5 right after start , then 13.5.

 

Voltage numbers sound good.

Some more history might help. Is this car new to you? Any other recent work?

The reason I ask is I’d expect to see some misfire codes along with the rough running. But IIRC, those codes don’t set right away, but only after driving several minutes. But if the problem is severe enough that you can’t really drive the car, we’re at a disadvantage of not receiving that additional troubleshooting information.

 

i got this car some time, well i do alot of work, both catalyst new, new coils, sparks, intake gaskets , before i got some missfire codes and catalyst codes , so i change that all this stuff what i wrote. and it help but still is some problems with that, that's why i think its something with fuel / air , becouse sometimes car drive as 238hp should drive.

 

After all that recent work, did the symptoms change? Better or worse?

For example, some no-name aftermarket coils and O2 sensors are junk. Perhaps while fixing the original faults, you inadvertently caused new problems with bad parts.

Did you save the old coils? if some of them were still good, you might experiment swapping in the old ones.

 

i got old coils, old spark plugs, but the new one's where OEM, so i didnt think they are bad

 

here's a video how he run now, not good at all, full gas ofcourse

 

I'm pretty much out of ideas. Anybody else?

The one thing left is you still didn't mention if the symptoms improved or worsened after all that recent work. If worse, I'm still wondering if one (or more) of the new parts has failed.