Engine hesitation when under load...
#1
07-16-2007, 10:13 PM
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Engine hesitation when under load...
I own a 2001 xjr. The car hesitates or seems to bog down when underload. Driving the car conservatively around town is ok... but as soon asI step on it... it seems to pause... "lost"around 3000-4000rpm (through every gear)... for 4-10 secs... then seems to find itself... and go.It has been getting worse in the last several months. I have had the vehicle in for serviceseveral times but no success.
Things I have had done:
Fuel filter changed
Fuel system/pressure check
New spark plugs
MAF checked and cleaned
No codes.
If anyone has any advice to this issue... kindly respond. Any info would be greatly appreciated.
SMX
Things I have had done:
Fuel filter changed
Fuel system/pressure check
New spark plugs
MAF checked and cleaned
No codes.
If anyone has any advice to this issue... kindly respond. Any info would be greatly appreciated.
SMX
#3
07-17-2007, 09:42 PM
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RE: Engine hesitation when under load...
Hey there SMX and[sm=welcomesign.gif] to the forum. Sorry to hear about your problems and unfortunatley I can't help.
However, mayeb Jose or Nti or one of the resident Jagtechs can help. Hopefully someone will be along soon with soem answers for you.
Jim
#4
07-18-2007, 10:53 AM
#5
07-18-2007, 01:41 PM
RE: Engine hesitation when under load...
Let me jutst make sure, you've had your oil changed regullary right, ur not running oil that you changed like 8,000 miles ago are you, and youu've been using premium right?Just want to make sure, cuz it sounds like you have like a corroded engine or something,I can't think of the right word right now.
Unless it's something obvious like the two things I just stated, I'd advice just taking it in for a diagnostic test at a dealer of jag service place
Unless it's something obvious like the two things I just stated, I'd advice just taking it in for a diagnostic test at a dealer of jag service place
#7
07-18-2007, 09:01 PM
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RE: Engine hesitation when under load...
are you sure youchecked and confirmed fuel pressure ,you might be running rich... you'll probably have rich running codes.. the vacuum line for pressure regulator, can kink even more when heated up.. check the vacuum line for brittleness..whats your fuel trim?
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#9
07-19-2007, 12:51 AM
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RE: Engine hesitation when under load...
ORIGINAL: 93xj6
Let me jutst make sure, you've had your oil changed regullary right, ur not running oil that you changed like 8,000 miles ago are you, and youu've been using premium right?Just want to make sure, cuz it sounds like you have like a corroded engine or something,I can't think of the right word right now.
Unless it's something obvious like the two things I just stated, I'd advice just taking it in for a diagnostic test at a dealer of jag service place
Let me jutst make sure, you've had your oil changed regullary right, ur not running oil that you changed like 8,000 miles ago are you, and youu've been using premium right?Just want to make sure, cuz it sounds like you have like a corroded engine or something,I can't think of the right word right now.
Unless it's something obvious like the two things I just stated, I'd advice just taking it in for a diagnostic test at a dealer of jag service place
#10
07-20-2007, 09:31 PM
RE: Engine hesitation when under load...
I agree with Jag_Genius about fuel pressure. Have the shop check your fuel PSI under load. My car would hesitate/delay shift/not have "oomph" under accelleration (like on the interstate on-ramp, passing, etc). The "restricted performance" warning started coming on. Took it to the Jag dealer. My PSI was a couple pounds low under heavy accelleration. They suggested a fuel filter change and injector service. I also did a throttle body service for good measure. BINGO! No more issue 
.
Now, lots of pep. Shifts like it should under hard accelleration. You can actually feel the supercharger surging as you accellerate. Ummm... what's the word.... oh, yeah... exhilerating!
. Now, lots of pep. Shifts like it should under hard accelleration. You can actually feel the supercharger surging as you accellerate. Ummm... what's the word.... oh, yeah... exhilerating!
#11
07-20-2007, 09:34 PM
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RE: Engine hesitation when under load...
Codes:
P1603 EEPROM Malfunction
This is the only code which showed up. The code was cleared... and I have been driving it for a day. The hesitation issue still exists. No luck in finding out what it is...
The results of a fuel pressure check was 44psi. Does that sound right? And the fuel filter was also changed.
It is obvious there is a problem some where... but how come no codes?
P1603 EEPROM Malfunction
This is the only code which showed up. The code was cleared... and I have been driving it for a day. The hesitation issue still exists. No luck in finding out what it is...
The results of a fuel pressure check was 44psi. Does that sound right? And the fuel filter was also changed.
It is obvious there is a problem some where... but how come no codes?
#13
07-23-2007, 10:10 PM
RE: Engine hesitation when under load...
Has the tech checked the function of the mass air flow meter? My Jag dealer found that mine was malfunctioningadding to myhesitation problems under accelleration.My issues were multi-fold.Part of my lean and rich problem (depending upon throttle position and whether you where looking atbank 1 or 2) was reduced fuel psi - about 2 psi too low(apparently overdue filter change), malfunctioning mass air flow meter, and possibly dirty injectors and/or sticking throttle valve. In addition to the newmass air flow meter,the tech suggested a "fuel service" which included the throttle valve and injector cleaning. Your issue may have more than one cause. Since you have already replaced the fuel filter,I would suggestthe throttle valve and injector cleaning next. It certainly can't hurt and it may improve your situation. I would also look into themass air flow meter. If it's on the fritz, that may bepart of your problem, as well. Obvious question - youhave checked your air filter and filter housing for blockages (very dirty filter or a wayward critter, or two? - hey, it happens!)
#14
07-24-2007, 11:18 AM
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#15
08-02-2007, 11:52 PM
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RE: Engine hesitation when under load...
Update:
I was gone on a short vacation. The car still has the problem. The tech was unable to diagnose the issue.
I think it's time for the dealer. I called them and described the problem... again. They said that if there are no codes they can't really help me. That the computer in the jag is smart enough to shoot codes for ANY issue. He said he can start troubleshooting... but possibly hand me the car back after 4-5 hours of labour and a bill... but the car not fixed. I said it can't be very complicated. It should be easy for them to rule out any systems which aren't the problem. After a bit of talking... he said his shop manager will go for a ride with me. No charge and no appointment. Supposedly he is very knowledgable on jags. That maybe he could suggest what root to take. So that will be next week.
I was gone on a short vacation. The car still has the problem. The tech was unable to diagnose the issue.
I think it's time for the dealer. I called them and described the problem... again. They said that if there are no codes they can't really help me. That the computer in the jag is smart enough to shoot codes for ANY issue. He said he can start troubleshooting... but possibly hand me the car back after 4-5 hours of labour and a bill... but the car not fixed. I said it can't be very complicated. It should be easy for them to rule out any systems which aren't the problem. After a bit of talking... he said his shop manager will go for a ride with me. No charge and no appointment. Supposedly he is very knowledgable on jags. That maybe he could suggest what root to take. So that will be next week.
#16
08-03-2007, 09:01 AM
RE: Engine hesitation when under load...
I took my XJR to a "Jaguar specialist" who had the "diagnostic computer" but they werent able to pinpoint my problem. I took it to the Jaguar dealer and they nailed it right away. Of course, the total bill was $1,000 in addition to the stuff covered under warranty,but that's because I figured since the car was already in the shop, I'd get new brakes and front rotors and a few other little odds and ends. It still runs great! 
Give the dealer a shot at running a diagnostic.Itshouldnt cost that much and who knows - between the ride with the tech andthe diagnostic, they'll hopefully find your problem
Good luck! -Kent
Give the dealer a shot at running a diagnostic.Itshouldnt cost that much and who knows - between the ride with the tech andthe diagnostic, they'll hopefully find your problem Good luck! -Kent
#17
08-03-2007, 10:24 PM
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RE: Engine hesitation when under load...
I think XJRs have 2 fuel pumps in the tank, right? Unless you check the pressure (44 psi sounds a bit too high) under the load, you may not be able to check the pressure under the "actual" running condition. If rich or lean condition exists, I think the computer should have already told you so by popping up some codes. Well, the computer is not the most sensitive thing in the world though.
Good luck.
Good luck.
#19
08-06-2007, 11:48 PM
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