[xj] New Subscriber-83 XJ6 S3 coincidence... or fuel pump...what does pump sound like?

XJ
1

Thanks to Michael, Alex and Frank-

Also, Mark below describes EXACTLY! what my xj6 is doing, and I was
wondering…
the problem started happening after I had British Auto Center in Seattle
give it a tune up and change the water pump hoses. I think that included a
timing adjustment.

Is it just a coincidence that the problem happened after my tuneup?

I am tempted to rule out the fuel pressure regulator and O2 sensor because I
had them both changed about a year ago.
They wouldn’t go bad that quickly, would they?

The fuel pump has not been replaced as far as I know. So, if I open my
trunk and listen, I should hear it working? What does it sound like?

Scott Schreffler
83xj6 s3
Everett, Washington-----Original Message-----
From: Nelson’s [mailto:mark_nelson@telus.net]
Sent: Thursday, September 06, 2001 5:39 PM
Cc: ‘xj@jag-lovers.org’
Subject: Re: [xj] New Subscriber-1983 Jag XJ6 S3

Don’t rule out an ignition problem. I believe I had a similar problem a
few months ago. At first the symptom was hesitation when accelerating
from a stop. The problem really became serious while on holidays on a
rather remote highway. At speeds around 80-90 Km/hr and going up hills
(low rpm and open throttle) the engine was choking and stuttering big
time. I was concerned that I wouldn’t make it back to civilization. The
solution turned out to be a new coil, which also noticably improved the
smoothness at idle. But back to the fuel side of things-If you can see
or hear fuel being returned the the gas tank, I figure you know that
there is enough pressure from the pump to overcome the pressure
regulator. Ah, but what if the regulator is shot? I tested mine once by
removing it and hooking up the input of it to a regulated supply of
compressed air. At or close to the specified pressure, (sorry can’t
remember what it is) the valve will bleed off the excess pressure. It is
a bit of a process but you will know without a doubt that fuel pressure
is or is not the problem. Of course the alternative is to simply get a
garage to check the fuel pressure. But what would be the fun in that?

BTW, thanks for the suggestions on my wishbone bearing question. The
bearing races popped out just as you said. New bearings and races are on
the way. No shims were in stock but I’ll use what I have and tune up the
clearances later if need be.

Mark Nelson
XJ6, Mk1
Prince George, Canada

===================================================
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2

Scott, the pump makes an annoying whirrring.

Do you have a voltmeter/ohmmeter, by the way. If so, check the
resistance (Ohms) between the case of the O2 sensor and the chassis –
should be about 0 (less than 0.1 Ohms). If not, get a stainless hose
clamp to clamp a copper wire around the case of the sensor and attach
the other end of the wire to a lug that will fit under a screw or bolt
on the chassis nearby.

Now, take the voltmeter and set it to the 1 or 2 volt range and connect
it between the O2’s center lead and chassis. When the car is warm and
idling, the needle of the meter should fluctuate up and down around
.4-.8 volts, as I recall, about once a second – this is the indication
that it and the ECU are dancing together just fine.

You can also check the archives for the propane-torch test (remove it
from the car, of course)!–
Alex
79xj6L SII
86xj6 SIII
61 Sprite MkII
Menlo Park, Calif.

Scott Schreffler wrote:

Thanks to Michael, Alex and Frank-

Also, Mark below describes EXACTLY! what my xj6 is doing, and I was
wondering…
the problem started happening after I had British Auto Center in Seattle
give it a tune up and change the water pump hoses. I think that included a
timing adjustment.

Is it just a coincidence that the problem happened after my tuneup?

I am tempted to rule out the fuel pressure regulator and O2 sensor because I
had them both changed about a year ago.
They wouldn’t go bad that quickly, would they?

The fuel pump has not been replaced as far as I know. So, if I open my
trunk and listen, I should hear it working? What does it sound like?

Scott Schreffler
83xj6 s3
Everett, Washington

-----Original Message-----
From: Nelson’s [mailto:mark_nelson@telus.net]
Sent: Thursday, September 06, 2001 5:39 PM
Cc: ‘xj@jag-lovers.org’
Subject: Re: [xj] New Subscriber-1983 Jag XJ6 S3

Don’t rule out an ignition problem. I believe I had a similar problem a
few months ago. At first the symptom was hesitation when accelerating
from a stop. The problem really became serious while on holidays on a
rather remote highway. At speeds around 80-90 Km/hr and going up hills
(low rpm and open throttle) the engine was choking and stuttering big
time. I was concerned that I wouldn’t make it back to civilization. The
solution turned out to be a new coil, which also noticably improved the
smoothness at idle. But back to the fuel side of things-If you can see
or hear fuel being returned the the gas tank, I figure you know that
there is enough pressure from the pump to overcome the pressure
regulator. Ah, but what if the regulator is shot? I tested mine once by
removing it and hooking up the input of it to a regulated supply of
compressed air. At or close to the specified pressure, (sorry can’t
remember what it is) the valve will bleed off the excess pressure. It is
a bit of a process but you will know without a doubt that fuel pressure
is or is not the problem. Of course the alternative is to simply get a
garage to check the fuel pressure. But what would be the fun in that?

BTW, thanks for the suggestions on my wishbone bearing question. The
bearing races popped out just as you said. New bearings and races are on
the way. No shims were in stock but I’ll use what I have and tune up the
clearances later if need be.

Mark Nelson
XJ6, Mk1
Prince George, Canada

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.