98 concorde starting problems

I have a 1998 chrysler concorde LXi. Every so often it wont start, and
its happening more and more. so far there are only 2 conditions that
it wont start that often. when its low on gas, and when its hot. about
80% of the time when its above 70 or a sunny day even it just wont
start. I have had the plugs changed, battery, checked compression,
etc.

heres what happens: then engine will turn over, it just wont start.
every so often it does start, and it feels like its missing quite a
bit (3-4 cylinders). then other times it runs like a champ. aften it
gets running (even when it feels like its missing) I rev the engine a
few mins and it will run fine till its off.

I have taken it to many mechanics, spent close to $1k fixing it, and
everytime i get it back, the mechanics either cant find the problem,
or tinker with this/that and say they fixed it. PLEASE any suggestions
would be great.
my guess would be a fuel problem, but ive been told the fuel system is
fine.

 

Have it checked for codes.

Has anyone mentioned crank or cam position sensors to you? Also, if the
problem is intermittent, I don't see how someone could rule out fuel
system (pump) - unless they caught it in the act of failing and
determined that the pump was indeed working when it wouldn't start, in
which case they should have been able to isolate the problem.

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

 

These intermittent problems sure stink. My gut feeling is that you
have a fuel problem but that is purely speculation. If it won't act
up for the mechanic and there are no codes it really is hella hard to
fix.

You might get a fuel pressure gauge so next time it won't start you
can hook it up and see what the fuel pressure is. Also get a can of
starting fluid and see if you can get a little bit of a start with
that.

If the fuel pressure is fine then you know the pump is good.

If it doesn't try to start with starting fluid then you know that
spark is missing.

If it does try to start with starting fluid and the fuel pressure is
good then you know the injectors are not firing.

Not a great deal of help but it makes it a lot easier if the mechanic
at least has an idea of which system to troubleshot.

Steve B.

 

OK, this calls for going back to the basics in troubleshooting on this
engine.

Wait till it's hot and having difficulty starting. You may have to carry
a small tool set with you if you drive it somewhere.

When you go to start it and it doesen't catch on the first few
revolutions, stop the engine, open the hood, connect a fuel pressure
guage to the fuel pressure diagnostic port, then have an assistant
try cranking and watch the guage. The needle should immediately snap
to pressure and remain at pressure as long as your cranking.
Then stop, and pull a spark plug boot, plug it into a spare plug,
hold the plug with heavy gloves to the block, have the assistant
crank a few times more. See if you got good spark. Next,
stop trying to crank, (by now you should have been cranking it
about a minute with all the testing your doing) turn off car,
pull out one of the spark plugs and check to see if it's wet with
fuel.

If you don't have good pressure it's the pump, or a restriction in
the gas line or filter or some such.

If you don't have good spark it's ignition (electrical ignition parts
are sensitive to heat)

If the spark plug you pull out is wet with fuel, and you have good
fuel pressure and good spark, then it's the timing, crank sensor or
some such. If the plug is dry then the injectors aren't firing.

Last but not least, how many miles on this car and how has it's
oiling been handled during it's lifetime? You could be looking at
a timing chain that has slipped. This can be checked by a
competent mechanic.

Ted

 

http://www.autoforumz.com/eform.php?p=634475

My guess would be cam/crank sensor, What's the mileage on this vehicle? Has
the vehicle ever cut off as you are driving it or is it just a no start
first thing in the morning or first start of the day? Were there any fault
codes found when the vehicle was in the shop? O , what engine?

Glenn Beasley
Chrysler Tech

 

does it have a 2.7 engine
if it does the timing has to be checked

 

http://www.autoforumz.com/eform.php?p=634475

Explain this. I have never heard of that before, where did you get that info
from?

 

http://www.autoforumz.com/eform.php?p=634475

Or TSB 18-09-98 needs to be performed 2.7 and 3.5 engine that meet the
criteria and build specified build dates
Some vehicles may exhibit a hot engine no start, hot engine restart with a
rough idle, or hot engine restart/die-out. Some vehicles may also exhibit
misfire DTC's. This condition occurs after a 10 to 20 minute hot soak and
may be aggravated by alcohol blended fuels. Some vehicles may not restart
until the engine cools. Fuel vapor build up in the fuel rail may be the
cause for these conditions.



Glenn Beasley

Chrysler Tech

 

Ted Mittelstaedt wrote:

Correction of a few generalizations tha need to be tweaked for this
vehicle, otherwise good info.:

This is coil-over-plug, so the coil screws and coil would have to be
removed and plugged onto another plug, but it should work - just not as
easy and quick as non-coil-over-plug.

Unless this is a 2.7L (doubtful since it's an LXi), it has a belt.
Minor technicality - belt could have slipped).

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

 

maxpower wrote:

Damn! Is there some reason they can't use the phrase "vapor lock" in
those TSB's!!!???

Are we seeing in the problem that the TSB is reporting a consequence of
not having a recirc fuel system?

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

 

actually it does have a recirc fuekl system but it's done in the tank
if it's a 2.7 thgere is a good chance the motor sludged up and the chain jumped
a tooth

 

Yes but the fuel does not go to the injector rail and back to the tank
dumping out the hot fuel, so its not a recirc fuel system

 

Yes - I knew that - *BUT* for the purposes of preventing vapor lock in
the engine area, it does no good, don't you think? The recirc in the
tank consist of the pressure regulator (at the tank) dumping excess fuel
back to the tank from the pressure relief valve - not the same thing as
recirc'ing all the way from the fuel rail. With under hood temperatures
rising over the years, that's one of the reasons they had to abandon the
engine-mounted fuel pump and recirc the fuel. I guess the Chrysler
engineers forgot about that lesson learned.

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

 

Less chance of vapor lock with the return less system since the
fuel does not pick up engine heat (the whole point of the return
less system).

 

really!!!!!!!! my 72 cudda and my 69 newport both have engine mounted fuel pumps and
there is no vapor lock there

 

Uhh - read it again. I said "With under hood temperatures RISING OVER
THE YEARS [emphasis added], that's one of the reasons they had to
abandon the engine-mounted fuel pump and recirc the fuel."

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

 

I beg to differ. Without recirc, the fuel is in the engine area a while
soaking up heat. With recirc, cool fuel is always coming in at
relatively high volume, and the warmed fuel is going back to the tank,
and any global heating of the tank by that is effectively removed by
ambient temps surrounding the tank (plus the volume of fuel there is
(relatively speaking) almost an infinite heat sink. Sre - you shut the
engine off, and it's going to heat up, but if it starts out a few
degrees cooler, chances are much better that it will never reach the
vapor stage.

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

 

What?


Matt

 

Doesn't work that way.

 

less - chance - of - vapor - lock - with - a - return - less -
system. The - fuel - doesn't - pick - up - engine - heat - which
- is - carried - back - to - the - tank - raising - the -
temperature - of - the - entire - fuel - supply - making - it -
more - susceptible - to - vapor - lock.

You and Bill may not find the above to be in the least bit
palatable. I suggest you take it up with the engineers who
design the systems, since it's their description as to why it's
done that way. The chief benefit being that it's easier to meet
OBD2 EVAP compliance, the side benefit being improved hot
driveability.

I could regale you both with stories of GM police cars that
after 2 shifts became un-driveable because the fuel temperature
had risen so high that the vapor pressure allowed the purge
system to overwhelm the fuel delivery system.

BTW, the OP needs a new fuel pump module, common failure mode.