1999 xk8 lean both banks
#1
1999 xk8 lean both banks
I let my 99 xk8 sit due to working from home since Covid and I’m now trying to get it run again for my 16 year old son. I have fixed bad fuel injectors and coil pacts but started getting a lean in both banks once those were handled. I have replaced the leaking fuel pressure regulator and the fuel filter. At this point I’m thinking I have a defective regulator or the cheep O’Riley fuel pump I did years ago is just not pumping enough fuel. One thing I have noticed is when I replaced the fuel pump years ago I would hear it buzz when I turned the key to the on position. I don’t hear anything now but I do hear it when I force the relay closed. So the question is does this sound like a fuel pump issue? If so would you think I should replace the aftermarket pump with a oem one or could this be a different issue? Any suggestions would be appreciated.
#4
#5
I have but this makes me wonder if the one i swapped it for is the correct type. Where it runs still I would think it is but I will double check.
#6
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Location: Summerville, South Carolina
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RJ237 (09-11-2024)
#8
I apologize for the slow response my father passed expectedly but unexpectedly if that makes sense. Any ways I just did a vaccine leak test and did not find any issues including at the vvt seals I also went to the local parts store to see if we could get a test on the fuel pressure but I think there tester was bad because we could not get it to register at all even when it was squirting everywhere. I will call a local shop and see if they can get me a number on Monday. I did notice that it takes a second for the fuel pressure to build on after sitting for a while. That makes me suspicious of the regulator. Is there a chance I got a defective one?
#9
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if you have a Harbor freight - they carry them for $32
https://www.harborfreight.com/fuel-i...ter-58760.html
https://www.harborfreight.com/fuel-i...ter-58760.html
#10
I apologize for the slow response my father passed expectedly but unexpectedly if that makes sense. Any ways I just did a vaccine leak test and did not find any issues including at the vvt seals I also went to the local parts store to see if we could get a test on the fuel pressure but I think there tester was bad because we could not get it to register at all even when it was squirting everywhere. I will call a local shop and see if they can get me a number on Monday. I did notice that it takes a second for the fuel pressure to build on after sitting for a while. That makes me suspicious of the regulator. Is there a chance I got a defective one?
First, you should be dragged behind the shed and flogged with a length of fuel hose for using an O'Reilly part. Just kidding, but you really, really shouldn't use parts store stuff on your Jag. My best guess is that you have a bum fuel pump, based on the above. The pressure will fall over time when the engine is off. But it should be measured in hours and days, not minutes. For whatever that's worth. It's possible you have a bad regulator. I don't think it would cause pressure bleed-down but I suppose it could not allow sufficient pressure to the injectors. That's a bit of a stretch, but regulators are easier to change than fuel pumps. What brand did you use? You can check the diaphragm by applying vacuum to the nipple. (One of MY favorite pastimes, but I digress). Maybe swap out the regulator first, just in case? Regardless, first step is to get a pressure reading and go from there.
Last edited by Y2KJag; 09-14-2024 at 06:51 PM.
#11
#13
I was finally able to get a fuel pressure result looks like it stabilizes at 40 psi here is a video https://youtube.com/shorts/g5d1sYQl8...CawBW5mxSzJ1R7
#14
that was with it not running and us manually turning on the fuel pump via a relay bypass. The fact it took so long to build up pressure may be a clue. Anyways I tried a different maf sensor and same issue so I think that is ruled out. I may be buying a parts car that is in better shape than my car this week if I do I will be swapping my engine and trans over to that car…. In the mean time am I still looking at a weak fuel pump?
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