Update on XJ8
#1
Update on XJ8
hello all, just wanted to post this update hoping I could get some help again. I finally got my XJ8 back from the shop, and the car was given to me as is, in what I was thinking, was safe mode as the mechanic had told me, but when I arrived there, he told me that the car was functioning just fine, oddly. I drove the car off the shop, and it was working perfectly, and I mean perfectly. Perfect shifting, no smoking or weird smells, nothing. I took it to the car wash, and when I drove off the car wash onto the gas station that was right, besides the car wash, the car started to stutter, and shake, and the RPMs went down to around 400. Then the car turned off, and I had to push it to the pump. I genuinely thought that it had run out of fuel because it has done this before, since I can't tell when it's empty (my fuel gauge doesn't work). After $80 worth of fuel, I tried to start it back up, but it would crank, start, stay on for literally about one second, and turn off. it stayed like this for 40 minutes, while I let the car rest(?). I thought it was a bad fuel pump, so I went to the back to see if I could hear anything at all, and the pump sounded just fine. I tried doing a hard reset as well, to see if that would solve the issue, and that did nothing. eventually, after about 40 minutes of me just waiting in the car, not really doing anything, I tried again, this time, putting my foot on the accelerator and tapping it repeatedly. I heard the car turnover, and so I kept stepping on the gas over and over, until the RPMs went up, and it finally started. After this, I drove it home as quickly as possible without letting the car idle, because I knew it was gonna shut off. I Finally got home, and let the car with the ignition on to see if it would turn off, but it didn't. It stayed on at around 500 RPMs, perfectly stable and quiet. I'm so confused right now, this is clearly not a transmission or throttlebody issue anymore, or maybe it is, but it doesn't make sense that it only happens sometimes. It makes even less sense that the accelerator pedal tapping worked. I think the car hates me, because every time that I fix an issue, quite literally within that same day another issue pops up. Maybe the universe just doesn't want me to have a jaguar lol. Any ideas would be appreciated, thank you
#2
The next time you have the engine running, at idle with no loads on using a voltmeter take a voltage reading under the hood at the bulkhead, rearward of the passenger side shock tower. My car reads 14.5 volts. Then take a reading at the battery terminals (my car is 14.2 volts), then put the negative meter probe on the body itself, there should be no change. If you were to let the engine idle for about 10 minutes, *carefully* touch each terminal of the battery. If one them is HOT to the touch, it is likely the battery cable is defective and needs replaced. The older these cars get, I’m running into more bad battery cables. The braided battery cables develop excessive resistance that’s likely where the braids meet the ends.
If you put $80 worth of fuel in it, it must’ve been really low??? Is it possible that the fuel pump got hot and is causing the issues? Multiple times we’ve had cars towed in and they had just filled up from near empty and when they went to restart, the engine just died. The fuel pump let go. Maybe yours isn’t happy either?? I know you said you heard the pump though but I’m wondering about the volume as well.
If you put $80 worth of fuel in it, it must’ve been really low??? Is it possible that the fuel pump got hot and is causing the issues? Multiple times we’ve had cars towed in and they had just filled up from near empty and when they went to restart, the engine just died. The fuel pump let go. Maybe yours isn’t happy either?? I know you said you heard the pump though but I’m wondering about the volume as well.
Last edited by Addicted2boost; 03-23-2024 at 08:03 PM.
#3
#4
Thanks for the suggestions gentlemen, I will try to find what I can. I should mention the car has another issue, it loses throttle information at random. I mean it works just fine when cold, shifts and accelerates perfectly, up until it just loses throttle info and goes into limp mode.
And I realized the air intake tube to the throttle body was badly positioned and not tight enough
And I realized the air intake tube to the throttle body was badly positioned and not tight enough
Last edited by ericnunez; 03-25-2024 at 12:44 AM.
#10
#11
The first time this happened I had to wait 35-40 minutes for the car to finally turn on. I tried several times to start it and finally the last time it worked. But like I mentioned before, I had to tap the gas several times until the car "woke up" and slowly increased in RPMs. It's like it's not getting enough fuel pressure or something, and pressing on the gas repeatedly built that up enough for it to start.
#13
They register just fine, when the car died they went down and down until it shut off. Then when it finally turned on, the RPMs started to slowly go up. MAF maybe? I checked this morning and fuel pressure is just fine.
Last edited by ericnunez; 03-27-2024 at 08:35 PM.
#14
#15
Mafs generally don't cause stalling as even disconnected, the car will run mostly ok
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ericnunez (03-28-2024)
#16
Yes, RPMs register. This is how I noticed the car was starting to turn on, because the more I pressed the gas, the higher RPMs went. I think it started around 1,000 rpms and then went up with every tap.
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