[E-Type] Stalling problem... help!

E-Type
1

My 4.2L '69 has learned a new trick – stalling.

Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)

Fuel mixture too lean? Fuel pump? I’ve never had to tinker
with a dual carb set up – any advice (if you think this is
the problem) would be appreciated!

Also, for what it’s worth, I’m in northern California and
the weather is actually not cold at all these days…

Thanks!
Jon–
1969 4.2L convertible
San Francisco, CA, United States
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2

In reply to a message from JonCraw sent Sun 1 Nov 2009:

Having SUs, I am not sure about the fundamentals of the
strangleberg carburettors. What I do know is that choke affects
both the mixture and the idle. With SUs, pullin gthe choke half way
out only affects the mixture, fully out increases the idle speed as
well.

So… It sounds to me you might just have an idle problem. I doubt
it has to do with the fuel pump. To check that; pedal to the metal,
if it responds smoothly you’re okay. Can you keep it idling while
pressing the throttle pedal a bit?–
The original message included these comments:

My 4.2L '69 has learned a new trick – stalling.
Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)
Fuel mixture too lean? Fuel pump? I’ve never had to tinker
with a dual carb set up – any advice (if you think this is
the problem) would be appreciated!
Also, for what it’s worth, I’m in northern California and
the weather is actually not cold at all these days…

–
Andrys, '69 e-type 2+2 back on the road since 14.10.2009
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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3

In reply to a message from JonCraw sent Sun 1 Nov 2009:

Hi Jon—Sounds like it was behaving and now suddenly just woun’t
idle right? Check your throttle linkages, especially those to the
secondary butterflies if still connected. Turn in the idle screws a
bit and see if you can get it idleing right, and if so, the
throttle linkage was binding somewhere and freed up, thus lowering
you idle RPM. The whole linkage should be periodically cleaned and
lubed, especially the secondary and crossover linkages.

John–
The original message included these comments:

My 4.2L '69 has learned a new trick – stalling.

–
John Deren
New Jersey '69 2+2, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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4

In reply to a message from JonCraw sent Sun 1 Nov 2009:

Jon,

Been a long time since I messed with Strombergs on my
family’s Volvos, but I remember the rubber diaphragms had a
habit of spitting with some regularity. Could be the engine
is flooding out when you push the choke in.–
The original message included these comments:

Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)

–
Jack Terrick 66 FHC
Greensburg, PA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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5

In reply to a message from JonCraw sent Sun 1 Nov 2009:

First thing is to pop the air filter and cover off so you can see
the shuttles in the carbs. Rev the engine and watch that both
shuttles lift as the engine speeds up. If one doesn’t lift, the
diaphragm has a hole in it.
Also check to see that all the vacuum connections are tight as well.–
The original message included these comments:

Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)
Fuel mixture too lean? Fuel pump? I’ve never had to tinker
with a dual carb set up – any advice (if you think this is
the problem) would be appreciated!

–
Pete Peterson 70E(193K) 88XJ40s(253K & 242K) 94XJ40 (122K)
Severna Park, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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6

In reply to a message from Jaguarpete sent Mon 2 Nov 2009:

Thanks to all for the responses so far (Andrys, John, Jack
and Pete)

A few more observations –
Air filter off. I start the car with the choke all the way
out, no problems. As I rev the engine, I can see the
pistons going up and down in both of the carbs. When I rev
it pretty aggressively (up to maybe 2800 RPM) I can see the
secondary butterfly valves open, though only a tiny amount
At this point everything seems normal.

However, when I start to ease the choke in, the idle speed
starts to drop slightly (as it should) but when I try to rev
the engine, the car stalls.

As an experiment, I start the car (with choke all the way
out) and hold the engine at 2000 RPM using the pedal. I
then start to slowly push in the choke. The engine dies
once the choke reaches about halfway in.

At this point, I do NOT think it is a throttle linkage
problem. I also visually inspected/ wiggled all the hoses
and vacuum lines, and all of them appear to be ok.

The car was fine, then it sat for about a week, and now
suddenly it has this stalling problem.

Does this sound like a gasket/ diaphram issue? Fuel mixture
too rich/ lean? Help!

Thanks!
Jon–
The original message included these comments:

The original message included these comments:

Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)

–
1969 4.2L convertible
San Francisco, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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7

In reply to a message from JonCraw sent Mon 2 Nov 2009:

Jon,

I can’t vouch for this being your problem, but I can say that when
I had the same symptoms (also occured ‘‘overnight’’), it turned out
to be a major vacuum leak, resulting in a weak mixture. In my case,
it was due to a bolt dropping out that a previous owner had stuck
in the secondary throttle shaft hole when the secondaries were
removed. I later found the bolt on the garage floor… In your case,
it sounds like the secondary throttles are still in place, but the
source may still be a big vacuum leak. I think the bypass valve(s)
in the Strombergs have been known to cause this if the diaphragm in
the little bypass unit cracks and leaks.

-David–
davidxk '56 XK-140 OTS, '69 XKE OTS , '98 XK8
Monterey CA, United States
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8

In reply to a message from JonCraw sent Mon 2 Nov 2009:

Does it also backfire through the carbs as it dies? That’s a sign
of weak mixture. There is a fairly large hollow brass plug on the
bottom of the carb that screws into the carb body. Unscrew it and
inspect the small hole on the side of the plug. Make sure it is
open. Use a round toothpick or safety pin to clean it out.
Generally, it can plug with wax or varnish if you let the car sit
for extended periods of time. I pull the hot wire off the fuel
pump and let the car idle until the carbs run out of fuel when I
put mine away for that reason.–
The original message included these comments:

Air filter off. I start the car with the choke all the way
out, no problems. As I rev the engine, I can see the
pistons going up and down in both of the carbs. When I rev
it pretty aggressively (up to maybe 2800 RPM) I can see the
secondary butterfly valves open, though only a tiny amount
At this point everything seems normal.

–
Pete Peterson 70E(193K) 88XJ40s(253K & 242K) 94XJ40 (122K)
Severna Park, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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9

…I think you are narrowing it down to the diaphranm
LLoyd

Now occurs everywhere, simultaneously.  But it doesn't have to be

experienced the moment it happens. Every now that ever was is still exactly
when it was, when it was now. Then, in terms of perception, is nothing more
than all the nows that are no longer now. Thus, the difference between now and then is when.
–The Waystoppers Users’ Manual----- Original Message -----
From: “JonCraw” jon.f.crawford@gmail.com
To: e-type@jag-lovers.org
Sent: Monday, November 2, 2009 12:40:17 PM GMT -08:00 US/Canada Pacific
Subject: Re: [E-Type] Stalling problem… help!

In reply to a message from Jaguarpete sent Mon 2 Nov 2009:

Thanks to all for the responses so far (Andrys, John, Jack
and Pete)

A few more observations –
Air filter off. I start the car with the choke all the way
out, no problems. As I rev the engine, I can see the
pistons going up and down in both of the carbs. When I rev
it pretty aggressively (up to maybe 2800 RPM) I can see the
secondary butterfly valves open, though only a tiny amount
At this point everything seems normal.

However, when I start to ease the choke in, the idle speed
starts to drop slightly (as it should) but when I try to rev
the engine, the car stalls.

As an experiment, I start the car (with choke all the way
out) and hold the engine at 2000 RPM using the pedal. I
then start to slowly push in the choke. The engine dies
once the choke reaches about halfway in.

At this point, I do NOT think it is a throttle linkage
problem. I also visually inspected/ wiggled all the hoses
and vacuum lines, and all of them appear to be ok.

The car was fine, then it sat for about a week, and now
suddenly it has this stalling problem.

Does this sound like a gasket/ diaphram issue? Fuel mixture
too rich/ lean? Help!

Thanks!
Jon

–
The original message included these comments:

The original message included these comments:

Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)

–
1969 4.2L convertible
San Francisco, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

Search the archives & forums - http://search.jag-lovers.org/
Subscription changes - http://www.jag-lovers.com/cgi-bin/majordomo
Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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10

In reply to a message from JonCraw sent Sun 1 Nov 2009:

Jon, this looks as if the pistons are dropping too low to keep
enough fuel for the idle = poor depression in the depression
chamber. I would recommend 3 leads: remove the 4 top screws of each
carb and check that the depression holes are clean, check the
diaphgrams for eventual cracks, finally examine the seals at the
dampers screw-caps.
The fact that it happened suddenly does not imply that the 2 carbs
had the problem at the same time. One would have had it for some
time, but the idle was still ok with one running properly.
Good luck and please keep us informed of your findings.
Ralph
69 OTS–
The original message included these comments:

My 4.2L '69 has learned a new trick – stalling.
Here are the symptoms – Cold starting is fine with choke
all the way out. Idles fine, no problems. But, as soon as
I push the choke in even halfway, it stalls. This happens
even if the car is warmed up (e.g. the water temp gauge in
the middle range…)
Fuel mixture too lean? Fuel pump? I’ve never had to tinker
with a dual carb set up – any advice (if you think this is
the problem) would be appreciated!

–
Ralph1780
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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