First post, second Jag. 110,000 miles XJR Purchased it knowing the engine was throwing these codes:

P0174
P1674
P1111

Test drive has only check engine light on but didn’t show restrictive performance. The car had no power and was surging, aknots erratic. PO bought new with extensive maintenance records. Had a history of every major thing being replaced, several claims in the last five years of low oil when the oil was changed, and some history of restricted performance showing up on dash.

Local, trusted shop stated the catalytic converters were probably stopped up because it wasn’t driven hard enough and only for short runs. I cleared the codes and they returned. Found the band on the air intake from filter housing was loose. Tightened and did hard reset with battery cables. No more codes and drove better but still lumpy and surging. Was able to get full power but not consistently. Further investigation showed what looks like to be some oil leaking after being driven very hard. See a picture of plastic cover over the coils.

My larger concern is this sensor that is clearly broken in a seam is visible. Clear evidence that somebody tried to glue it back on to the valve cover. For what it is worth there is also a bolt that is laying on the frame of the driver side. My only other concerns is, I hear pretty loud popping or cracking sounds, which would typically come from an exhaust as it expands and cools after the car is shut down. However, in this case, you can hear it as you crank up the engine and it’s starting to warm up. Hence might be the reason for a comment that the catalytic converters are stopped up.

Any help would be much appreciated. And I’m hoping that I am explaining and showing all of this clearly.


I’ve also included pictures of the hose coming off of the air cleaner back to the engine. Clearly a decent amount of oil within that but the MAF looks clean.

 

I have videos of the dash and me driving the car. If that would help anybody see what I’m trying to describe.

 

Left valve cover port is part load breather port. It has tendency to speep oil out. While you have pipe out, clean the small hole with drill bit. Drill it with fingers only. I can not remember the drillbit size. Other pipe is full load breather and it goes to the intakepipe. When it was disconnected it caused big intake air leak.

 

I do recall reading about that in one of the stickies. Thank you for helping me identify what it is. In your experience with that cause any of my liability issues with the fitting and being cracked at the base?

 

Welcome, I would be looking at the fuel pumps. If it falls on it's face over 3000 rpm it's almost certain one of the fuel pumps is dead. Alternatively their strainers are jammed full, or fuel filter needs changing.
There is a shraeder valve on the fuel rail you can confirm fuel pressure - should be IRO 40psi.

Post the videos so we can see the behaviour - a word of caution, don't blast the engine until it's fully sorted out, or it gets really expensive really quickly!

 

I’ll have to go back and see at what point it drops. I have gotten full on power but thank you for the warning.

 

the oil filter cap doesn’t seem to seal. If I turn it to hard it slips and loosens up. After reading all the cautions on o rings and seals I have to wonder. There also seems to be oil blow by around the cap after I cleaned it up.

I drove the car for 30 minutes and looked at live data from the scanner. See screenshot but a few things stood out. Most of the issues were under 3K RPM and anything above that was barely noticeable.

I questioned to pull out in front of anyone and was thankful no one was following close to get aggravated with how slow it took me to accelerate.

STFT 0%.
LTFT 0%. “ “ “ 0.02 - 0.03

The O2 sensors Voltage fluctuated between 0.02 - 0.04 and a little less on bank 2. I will highlight what stands out to me on the data and hope that helps. My videos are too large to upload though.

Thanks again.

 

P1111 was great but clearing the codes will have lost it. You want it back. Until then P1000 means one or more OBD monitors is unset. Each unset one prevents a bunch of codes being flagged.

Most codes are 2-trip i.e. can only flag if they occur on 2 engine warm ups.

Worth looking at fuel trims via live data (with hot engine) at idle to see if you've an air leak on one or both banks.

 

Out of interest, is your MAF sensor OEM or an aftermarket replacement?

When I had my XJR it would behave similarly to what you describe until we noticed the MAF was a non OEM item. We fitted an OEM part and it fixed it immediately.

The XJR has a different MAF to the XJ8, so not only did I have a pattern part fitted it was one intended for a non supercharged car.

 

I've read on these forums of running problems due to leaking breathers, I've not quite understood why but it seems to really upset the ECU. So you might need a new cam cover to sort it.

As the plastics are obviously past their best it's also worth carefully inspecting the intake pipe as they do split on the belows & cause unmetered air leaks which also through up various problems.

 

Great suggestion guys. I will start working through the list. I used a coating of E 6000 around the breather valve that had the crack at the base yesterday. The MAF is a DENSO S/C unit and once I figure out how to post these videos. Hopefully it will help everybody understand

a little bit better. Thanks again. I really want this car to be a dream and not a nightmare.

 

OK, I thought it may be worth asking about the MAF as that was the problem on my car along with a dead fuel pump. Once the pump and MAF were replaced it behaved perfectly.

Speaking of perfect, I notice that like me you also have an XC70 which is quite frankly the best car I’ve ever bought. It is the Swiss Army knife of cars and I absolutely love mine to bits. I wholeheartedly intend to keep mine for as long as possible.

 

Thanks STU, I’ve had several Volvos over the years and they have all been my favorite. S80 and V70R were polar opposites but fantastic in their own way. I play games with myself and if a car on my bucket list checks all the boxes (year, color, options, keys and passionate owner) I’m down to buy. Only a few cars on my list have disappointed. Cadillac Allanté being one, but I still look at them.

 

I spent an inordinate amount of time with fuel trims and the attendant OBD codes until I replaced the oil cap which was leaking due to the O-ring being old on one of my cars. I suppose if a correct O-ring could be sourced, that would work but I never could find on the fit correctly and just bought a new cap.

 

Check on ebay for a replacement part. Fixing oil leaks will save you trouble later. I used to get oil collecting in the spart plug holes. Does not run well. Clean the MAF. The car has lots of computers that do not do well with a old battery. All the plastic lines in the engine bay
are crap, Keep spares. Engine bay electrical connectors get brittle and the rubber seal allow oil etc to get in. Contact cleaner. If you keep everything up, it becomes a dependable machine.

 

Thank you for the advice. I’m going to create a separate post showing the condition of the spark plugs today. I’m working to get an overall health report and to see what needs attention. Checking hoses, filters, connections. The spark plugs were changed 750 miles ago but that was over 2 years ago. I’m shocked how bad they look considering the limited time in the car. I’m starting to agree with the PO mechanic saying the catalytic converters are stopped up and limiting flow. I know I want to get her running so I can throw a smile on my face.

 

From the picture I can say that at 20% tps I don't think with that rpm map should not be close zero vacuum. I haven't measured my R vacuum behaveour that closely. What I do know is that short term trim and long too will go to 0% because you have throttle opened close to 20%. Engine is going in to the base map area where closed loop is going off and it is waiting for the boost. But I can not remember how low tps% more specially load% it does this
To view short or long trim. You have to stay in cruise engine state.