S TYPE R fuel pump shuts down
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Joined: Jan 2011
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From: N.R.H. Texas
Time to take a breather...... Lots of input here, some of it misleading.
For 2005:
XK8/XKR -- one fuel pump only.
X-Type, S-Type Normally Aspirated and XJ NA -- Fuel Pump RH, Jet Pump LH
[Jet pump sends fuel from LH to RH side to be available to Electric pump]
S-Type Supercharged and XJ Supercharged -- 2 Fuel Pumps, RH & LH
[Pumps are in parallel and run together, all the time]
I think it would help some to seek out the Fuel Trim FAQ and read the two papers. In this case, with the car running so bad under load, the fuel trims are only responding to the misfires. Misfires flood the exhaust with oxygen that didn't get burned and the trims go haywire. Consequently, they seem to indicate air leaks.
The misfire cause should probably be the central issue. Just based on the original description I tend to come down on the plugged catalyst possibility. You have to consider the 'self preservation' functions designed into these systems, and consider the ECM may be shutting down the pump or pumps to prevent a catalyst meltdown.
That may not be the case, but by the same token, catalyst substitution may be the only conclusive diagnostic strategy, one way or the other.
My two cents.......
For 2005:
XK8/XKR -- one fuel pump only.
X-Type, S-Type Normally Aspirated and XJ NA -- Fuel Pump RH, Jet Pump LH
[Jet pump sends fuel from LH to RH side to be available to Electric pump]
S-Type Supercharged and XJ Supercharged -- 2 Fuel Pumps, RH & LH
[Pumps are in parallel and run together, all the time]
I think it would help some to seek out the Fuel Trim FAQ and read the two papers. In this case, with the car running so bad under load, the fuel trims are only responding to the misfires. Misfires flood the exhaust with oxygen that didn't get burned and the trims go haywire. Consequently, they seem to indicate air leaks.
The misfire cause should probably be the central issue. Just based on the original description I tend to come down on the plugged catalyst possibility. You have to consider the 'self preservation' functions designed into these systems, and consider the ECM may be shutting down the pump or pumps to prevent a catalyst meltdown.
That may not be the case, but by the same token, catalyst substitution may be the only conclusive diagnostic strategy, one way or the other.
My two cents.......
Last edited by Bobco51; Feb 16, 2012 at 04:05 PM.
Joined: Sep 2010
Posts: 2,114
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From: Indianapolis, IN
saw a plugged cat instance on another thread str not running right but i had to remove most of my post because as was mentioned it got confusing real fast so i started fresh. xjrguy what is you input on swapping coils side to side to see if it follows indicating coil breakdown
Logical step, go for it!
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From: N.R.H. Texas
Yes hard to believe all coils on one side are breaking down at the same time, i am yet to see more than three at a time and there is an obvious misfire.
Last edited by Bobco51; Feb 16, 2012 at 07:03 PM.
Failures of all coils on one side is not the norm but failure of an item that is related or controls those coils is possible. This situation is out of the norm so please post what you find.
Joined: Sep 2010
Posts: 2,114
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From: Indianapolis, IN
I wasn't actually suggesting total coil failure on one side was the cause here, my point was that at this juncture since it would be so easy to do, he might as well give it a go. Maybe we'll be surprised and the misfires will move, but I doubt it. After everything he has reported, I'm still hangin' my hat on a catalyst issue.
And I'm sorry about this Gus, but I have to ask this question:
Bobco, does this car currently have platinum, surface gap or split-fire spark plugs in it?? It should have iridium plugs.
Cheers,
And I'm sorry about this Gus, but I have to ask this question:
Bobco, does this car currently have platinum, surface gap or split-fire spark plugs in it?? It should have iridium plugs.
Cheers,
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Joined: Jan 2011
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From: N.R.H. Texas
Problem resolved, I did not swap coils i went for the fastest way to test the cat, I simply removed the front 02 on suspected bank and now rev over 5K easy
Thanks for all the input
Bob
Thanks for all the input
Bob
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From: Yorkshire, England
Misfires / air leaks which are either not noticed or ignored would be my vote. Time and again we get people who've ignored the "idiot" light, may even have frequently cleared codes, and finally have to do something if they need a state inspection or the car stalls etc.
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