Need help with a problem with my 3/4 lump (Chevy 4.3 Vortec V6,
4L60E transmission)in my 1965 Mk2. I am using the fuel injection
and computer from the Chevy.
On three recent trips, the engine shut down as if the key was
turned off. She would crank but not fire. All three times the
weather was hot (90deg.+)and I had driven for several miles, with
the AC running. I did notice the high-pressure fuel pump kept
getting louder & louder.
The first time I thought I was out of fuel. AAA arrived about an
hour later with the gas & she fired right up.
The second time I just waited about 20 minutes (I knew I had plenty
of fuel) & she fired right up.
I replaced the fuel pump.
The last time nothing worked. Had her towed to my friendly
mechanic. He hooked up the code reader & found the computer
was ‘‘locked up’’. He cleared all of the codes & she fired right up.
I have lost confidence in taking her on even medium length trips. I
have bought a code reader in case it happens again I will be able
to clear the codes wherever I am.
Does anyone have any suggestions as to what might be the culprit?
All replies appreciated.–
Chuck Welch 1999 XJ-8, 1965 Mk 2, 2004 Triumph Bonneville
Loveland, OH, United States
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In reply to a message from OLDKAT sent Sat 30 Jul 2011:
Its not a matter of just clearing the codes to get it to run, you
need to read the codes and fix what they are telling you is wrong.
Until you fix the root causes, the codes will keep occurring and
you will continue to have problems.–
lockheed 92 XJS Cpe/97 LT1 Miami FL/ 96 XJS Cv 4.0 Austin TX
Austin, TX, United States
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In reply to a message from lockheed sent Sat 30 Jul 2011:
Good point.
That is why I bought the reader - so I can see the codes & correct
the problem. I was hoping to try to avoid another stranded-by-the-
highway event.
One suggestion is that the ignition module is failing when it gets
hot.
Thanks–
The original message included these comments:
Its not a matter of just clearing the codes to get it to run, you
In reply to a message from OLDKAT sent Sat 30 Jul 2011:
IMHO, I think you have problems with at least one ground,
maybe the one to the transmission, but somewhere. Maybe the
codes can lead you to find it, or maybe not, but use your
reader to at least run the tests for each one you get - the
Vortec engine is documented fairly well on the internet and
there is a Haynes manual just for that engine.
Bad grounds can make the codes come at you from all over the
car, but it can also screw up a fuel pump.–
The original message included these comments:
and computer from the Chevy.
mechanic. He hooked up the code reader & found the computer
was ‘‘locked up’’. He cleared all of the codes & she fired right up.
In reply to a message from fiveo sent Sun 31 Jul 2011:
I would also suspect module and would look at replacing the mag
pick up while your in there. Those 4.3’s (depending on the year)
had an issue with the dizzy’s cracking the reluctor ring, but I
don’t think that your issue here. I would also look at ground strap
issues and whether you have enough of them, and the quality of them.–
Rob Wade
Windsor Ontario, Canada
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In reply to a message from Rob Wade sent Sun 31 Jul 2011:
Well, she failed me again.
Driving under hot (90 degree) conditions, 25 miles at highway
speeds, & she just quits & won’t start. Turns over fine but will
not fire up. I connected the code reader & there were NO CODES.
Disconnected/reconnected battery, no help. Let her sit 20 minutes &
she started.
I have replaced the fuel pump, fuel filter, & ignition control
module.
One noticable thing is that the electric high-pressure fuel pump,
which is mounted in the trunk, gets VERY loud-like it is running
much harder/faster than normal. When she won’t start, & I turn on
the key, the fuel pump sound is ‘‘different’’. Hard to explain, but
there is definitely a different sound to it.
I’m running out of ideas. Any suggestions?
Thanks–
The original message included these comments:
I would also suspect module and would look at replacing the mag
don’t think that your issue here. I would also look at ground strap
In reply to a message from OLDKAT sent Sat 6 Aug 2011:
WAG:
No vent to tanks. Vacum forms as puimp draws fuel out. Then vacum
overcomes pump and it whirrrs loudly, no fuel in it.
Time goes by, vacum is displaced by incopming air. All is normal.
Car runs til cycle repeats.
When this occurs again, open fuel cap, if greeted by a large
whoosh of incomin g iar, you’ve got it.
If your car isn’t so sophisticsted as to refuse to run with a
cracked open fuel cap, try that.
My WAG, again, tank vent issue.
Carl–
The original message included these comments:
Driving under hot (90 degree) conditions, 25 miles at highway
speeds, & she just quits & won’t start. Turns over fine but will
not fire up. I connected the code reader & there were NO CODES.
One noticable thing is that the electric high-pressure fuel pump,
which is mounted in the trunk, gets VERY loud-like it is running
much harder/faster than normal. When she won’t start, & I turn on
the key, the fuel pump sound is ‘‘different’’. Hard to explain, but
there is definitely a different sound to it.
Are you sure the ECM is not suddenly losing power somehow? Maybe your feed relay is bad, or power from the ignition switch is intermittent.
What about your check engine light?? Did it come on when the engine died? Is it on during the time you are having the hard starting problem, or off?? If it’s off, that shows the ECM is not getting power while you’re trying to start.
Id you don’t already have it, get the factory manual for the donor car and go through the “cranks but won’t start” checklist. That’s the only way to definitely find the problem. Anything else is guess work, and can get very expensive with these engines…
I don’t have check engine light installed on my Mk2.
I do have the manual for the S-10 donor, so I’ll look there.
Thanks–
The original message included these comments:
Are you sure the ECM is not suddenly losing power somehow? Maybe your feed relay is bad, or power from the ignition switch is intermittent.
What about your check engine light?? Did it come on when the engine died?� Is it on during the time you are having the hard starting problem, or off?? If it’s off, that shows the ECM is not getting power while you’re trying to start.
I would think that CadJag is right. This could just be one of the
Jaguar problems acting up ( ‘‘whooshing gas tanks’’ from vacuum in
tank - not venting enough air into the tanks as the fuel is used.
Fuel pump eventually strains against the vacuum (loud pump) and
failure. I would also bet that the episode happens during a
susained drive where the amount of fuel STEADILY required by the
engine is in excess of the air entering the fuel tank and
eventually the vacuum builds until the pump can not pump at all.–
Alyn
Seattle WA, United States
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With all due respect, what he really needs to do is look at a shop manual for the donor car and go through the specific steps to isolate the problem. Fuel delivery issues are on the list of things to check (fuel pressure monitoring at the rail at different times, etc.,.). That’s how problems are solved with these modern drivetrains. Without the manual, fixing this is like shooting in the dark…
I would think that CadJag is right. This could just be one of the
Jaguar problems acting up ( ‘‘whooshing gas tanks’’ from vacuum in
tank - not venting enough air into the tanks as the fuel is used…
I would agree that the diagnostic paths in th manuals are the right
way to do it.
Note, my post included WAG. We all know what that stands for, but,
sometimes, it works. Actually, the noisy pump is a clue, so it
isn’t all that wild. Disciplined, nope.
Now, tomorrow is surgery on one of my 2 cycle Weed Eaters. No
diagnostics there that are worth beans, so, it’s the old way.
Carl–
The original message included these comments:
With all due respect, what he really needs to do is look at a shop manual for the donor car and go through the specific steps to isolate the problem. Fuel delivery issues are on the list of things to check (fuel pressure monitoring at the rail at different times, etc.,.). That’s how problems are solved with these modern drivetrains. Without the manual, fixing this is like shooting in the dark…
In reply to a message from cadjag sent Tue 9 Aug 2011:
Addendum:
If it is manuals that have the answer, the manual for the host car
might also be of assistance. Some parts of te host car are involved
in the fuel delivery issue.
I understand that the issue has not yet been identified as ignition
or fuel. Isolating it to one of these would be a large step forward.
Carl–
The original message included these comments:
Now, tomorrow is surgery on one of my 2 cycle Weed Eaters. No
With all due respect, what he really needs to do is look at a shop manual for the donor car and go through the specific steps to isolate the problem. Fuel delivery issues are on the list of things to check (fuel pressure monitoring at the rail at different times, etc.,.). That’s how problems are solved with these modern drivetrains. Without the manual, fixing this is like shooting in the dark…
In reply to a message from OLDKAT sent Sat 6 Aug 2011:
I have finally duplicated the previous driving conditions and she
did not miss a beat.
It seems the gas tank was forming a vacuum due to inadequate
venting (suggeation came off list & I don’t know who sent it -
whoever it was is my new best friend).
Drilled some extra holes in gas cap to help her breathe.
Anyone want to buy a like-new High Pressure fuel pump or ignition
conrol module for a 4.3?
Thanks for all replies.–
The original message included these comments:
I don’t have check engine light installed on my Mk2.
I do have the manual for the S-10 donor, so I’ll look there.
