98 concorde starting problems

Greg, you might want to go back and re-read the OPs post, the
hard/no start occurs under two conditions;
1) Low fuel level
2) Ambient above 70 degrees

Neither one of these conditions is worth attributing to vapor
lock.
Hell, I just drove over 100 miles on Sunday in 100 degree heat in
a carbureted car with an engine mounted mechanical fuel pump, the
coolant was running at over 230 degrees, the gasoline is
reformulated piss water and I experienced absolutely no evidence
of vapor lock.

Sorry, at 72 degrees, he doesn't have vapor lock.

He has the classic pattern failure of a weak fuel pump.

Which means that the vapor lock is a symptom, not the cause of
the problem to begin with, i.e., he has a failing fuel pump.

All well and good, except that it doesn't fit the OPs description
of when the problem occurs.
Wrong diagnosis.

I guess if you follow the TSB, you -might- stumble upon the root
cause for the no start.
Thing is; I have numerous customers who own 2.7 LH cars and they
do not suffer wholesale vapor lock problems with their cars under
-any- ambient temperature conditions.

The OPs problem occurs at ambient temperature above 70 degrees
with low fuel level. No mention of a "hot engine," so the TSB
doesn't fit.
A simple amp meter hook up to the fuel pump circuit will show
lower than normal amperage draw for the fuel pump which means
it's spinning faster than normal, it's spinning faster than
normal because it's cavitating, it's cavitating because the pump
is worn out and lacks sufficient volume to maintain an adequate
level of fuel in the cup at the bottom of the fuel pump module
(via the return line) so the pump is starving.
If you guys had the slightest clue of how this system -actually-
works, and had actually paid attention to the customers
complaint, non of this back and forth crap would be necessary.

Sounds like a fuel pump failure, not vapor lock.
Vapor lock occurs in spite of a properly functioning fuel supply.
Frankly, I haven't seen a case of vapor lock in near 25 years,
but then, I DO know to recognize the symptoms when they are
presented (like the OPs mention of missfiring when the problem
occurs).

 

In order to facilitate a MPFI fuel system that does not have a
vacuum operated fuel pressure regulator it is necessary to modify
the injector driver circuit so that the injectors can be
multi-fired to achieve adequate fuel delivery, this means heavier
duty - higher quality drivers in the PCM. It's entirely likely
that the increased costs of these injector drivers offsets any
dollar saving realized by not having to use a dozen or so feet of
1/4" fuel line. Especially if one considers that the PCM is
under warranty a lot longer than the fuel line(s).

Center mounted window switches have been around a lot longer than
buss controlled body functions. Buss networked systems in and of
themselves eliminate many feet of wiring which is the whole point
of using buss circuits to begin with, so it's really not germane
to -where- the switches are positioned.
YMWTC; Japanese cars have typically had the dome light over-ride
switch built into the dome light itself (where it's reachable
from every seat position).

 

Which means that none watch this ng.

Actually, I've had practical experience with both cars and airplanes and
an engineering degree that gives me a little understanding of the
subject. What is your experience and credentials?

I'm not familiar with OBD2 EVAP criteria, so why don't you fill me in
since you know so much about it?

Only while the pump is operating. Most vapor lock problems, both in the
old days with engine mounted pumps and carbs or today, occur while the
car or airplane is sitting after being run hard and hot. Vapor lock is
relatively rare during operation.

It has everything to do with what we've posted and next to nothing with
what you have posted.

I'm not familiar with LH cars, I was talking cars in general. The
routing of the fuel line is a major contributor to vapor lock
susceptibility and the reason why some cars are famous for this problem
and some rarely have it. A properl routed and insulated fuel line will
greatly reduce the likelihood of vapor forming in the fuel line.

Fuel temperature is highly relevant, but not in the tank ... in the fuel
line in the engine compartment.

Positive pressure isn't always maintained while the vehicle is sitting
with the fuel pump turned off. Check valves tend to age and leak.

You know the root cause of one form of vapor lock, but not every form
obviously. And you seem to live in an ideal world where pressure is
always maintained between the pump and the fuel injector. Taint so.

Sure if the maker was stupid enough to run it along side the exhaust
system. I haven't yet seen a car designed that way, but I'm sure
somebody somewhere has done it. And the heat from the pavement pales in
comparison to the heat from the exhaust manifold.

Matt

 

His ignorance of vapor lock in autos is exceeded only by his ignorance
of vapor lock formation in airplanes.

Thinking that you will heat the fuel in the wings while flying is a real
hoot!

Matt

 

You keep mentioning a bad check valve relesaing the fuel rail pressure -
don't forget a leaking injector.

Speaking of running a fuel line next to exhaust, I bought a 1980
Citation brand new - V-6. It would vapor lock after a heat soak because
they had the mechanical fuel pump mounted on the front (bumper side) of
the transverse engine, and the front bank main exhaust pipe came off the
collector pointing forward about 6" away from the fuel pump and did a
perfect 180° with the fuel pump at the exact center of radius. Nice
design!!

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Especially since the return lines are part of the design to reduce vapor lock
during hot starts. Vapor lock isn't a problem when the engine is running, just
when you feel like starting the engine again before it cools.

 

So does my LH vehicle.

I am curious what "heavier duty - higher quality drivers in the PCM" are and why
these drivers cost more

 

You are mistaken re: original post. xmirage2kxsaid that the problem occurs "when
its low on gas, and when its hot." He also said that 80% of the time it is over 70
degrees/sunny outside. As discussed in Chrysler's TSB, vapor lock is caused by
heat from the engine, not ambient heat, although an engine cools more slowly when
ambient temp is higher. Your experience with a carbureted car is not relevant to
the discussion; the discussion (and the Vapor Lock TSB for that matter) is about a
1998 Concorde.

 

Which means that none watch this ng.[/QUOTE]

Could you possibly be a little more absurd?

Yet farther down you admit to having no familiarity with LH cars.

I don't believe the vehicle in question is the French built SST.

For all I know, you design toilet plungers.

On my resume I usually just put "dumb fucking country mechanic."
Ya see Matt, the importance of glitzy job titles and education
bench marks lost it's luster long-long ago.

Gee, I guess you really don't have the practical experience as
you claim.

The TSB that Greg Houston cited mentioned "miss fires" do you
suppose they occurred while the engine was shut off?

Oh, so all those cars that stalled in traffic, they must have
just pulled over to take a piss on the side of the road then, 'eh?

Well no since the OPs symptoms occur at 70 degrees or above, that
isn't a high enough temperature to induce vapor lock.

Okay, give me a car in general where the fuel line is routed near
the exhaust manifold.

And this has what to do with a car that won't start when the fuel
level is low and/or the ambients are at 70 degrees or above and
these specific symptoms lay blame to a return less fuel system
exactly how? Bear in mind, my 98 Intrepid *has* a returnless
fuel system and it started just fine on Sunday when it was over
100 degrees with 1/8th tank of fuel.

I disagree. If the fuel is already heated, adding the delta T
from the engine compartment is only going to make matters worse.

Well, thank you Matt. Imagine, it only took this long to get to
the root cause and it's attending symptoms.
Wow, worn failed parts cause X, Y and Z to happen.

Maybe we should wait to hear from those who own second generation
LH cars with recirculating fuel systems to see if they have fewer
or more problems with vapor lock, just for the sake of fair
comparison.

Oh, I don't know about that Matt, I built my first fuel system
check valve leak testing tool 24 years ago from a spare radiator
pressure tester. I deal with this stuff daily, you on the other
hand obviously don't.

Earlier, you posted:
Would you like to borrow my napkin?

 

You can either cite where I mentioned "while flying" or summarily
go **** yourself.

Must suck to be Dilbert, "eh?

 

You bring up an interesting point Bill.

That fuel line was designed by an engineer.





Oooops, wait...

-You- are an engineer.

So is Matt. (but Matt flies airplanes which somehow makes him
superior)

Hold it.....

Didn't you mention having designed fuel pumps at one time in your
career?

Could it be?

You guys are a riot!

 

Okay, I'll bite...

How exactly does the return line "reduce vapor lock?"

 

Oh, maybe because they can handle higher current for longer
periods of time without failing.
Or, maybe they handle the same amount of current for longer
periods of time without failing.

Or even, they handle lower current at a higher duty cycle without
failing.

Or, maybe it has something to do with Matt performing his
pre-flight check list while he's airborne?

 

So where does xmirage2kx say that this is a "heat from the
engine" problem.

He cites two criteria;
1) Low fuel level.
So explain how low fuel level contributes to vapor lock
2) 80% of the time it's over 70 degrees and sunny out.
So, explain how either of these conditions contribute to the
"engine heat" situation that is germane to the TSB you keep
crowing about?

Or is that you just don't get it?
The TSB doesn't apply.
Wrong diagnosis.
Warranty claim rejected.
Money spent, customer screwed again.
I will not argue that there is apparently a problem of sorts that
the TSB addresses, never said there wasn't.

You guys have never met a wild goose chase that you didn't love,
have you?

Just proves the old adage....

A TSB in the wrong hands is dangerous.

 

As explained several times earlier in the thread, a return line provides fresh fuel
from the tank that has not been warmed locally from the engine to higher
temperatures. Fuel returning to the tank has a higher temperature than the tank,
but little more specific heat per mass due to the low volume compared to the tank
volume. That is the raison d'etre of return lines on fuel injected aircraft
engine systems. Today's cars use a pressurized fuel system that maintains
pressure (supposedly) for a while when the engine is off and warm.

 

You did state, "Run the aircraft for enough hours to sufficiently heat the fuel
and the problem will return I suspect." Aircraft engines are typically not run
for hours on the ground during normal operations. Needing to resort to profane
language does not assist your argument.

 

What is "they?"

Huh?

 

As I quoted earlier, the exact statement from the OP discussing his car is "when
its low on gas, and when its hot."

Got it.

The TSB does apply.

The diagnosis is part of the TSB.

What warranty claim are you referring to in the context of what is *actually* being
discussed?

The vehicle is exhibiting symptoms specifically mentioned in a TSB for the same
model year. It is reasonable to do the diagnosis procedures in the TSB.

 

Oh no! Not another guy who has a chip on his shoulder because he didn't
go to college and someone else did. Sorry about that - I wish you could
have gone, but not my problem.

So your logic is: (1) Some engineer did a crappy system design (2) I am
an engineer (3) Therefore I am stupid too. That logic reflects on you
not me, and is an extension of the chip on your shoulder (your emotion
takes over your brain in certain situations so that you make irrational
statements).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

You keep bringin up the "above 70°" thing. Don't you realize that
underhood temperatures (inculding fuel rail temperatures) will be
directly affected by rises in ambient (i.e., a degree of ambient temp.
rise will add about 1° to the rail temp.). Certainly you understand
that the underhood temperatures are higher than the ambient? Perhaps
you should sit in on a heat transfer class at a nearby engineering
school (sorry - couldn't resist).

Also, as someone else already mentioned, perhaps the OP got ahold of
some fuel with high alcohol content - combined with some other problem
that is making a marginal problem an actual one. Besides the bad check
valve that has been mentioned several times, a leaking injector could
also explain system depressurization after shut down.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')