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.
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xmirage2kx wrote:

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')
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On 22 Jul 2005 22:35:48 -0400, xmirage2kx

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.
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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
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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')
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http://www.autoforumz.com/Chrysler-98-concorde-starting-problems-ftopict130227.html
http://www.autoforumz.com/eform.php?pc4475
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
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does it have a 2.7 engine if it does the timing has to be checked
xmirage2kx wrote:

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request
http://www.autoforumz.com/Chrysler-98-concorde-starting-problems-ftopict130227.html
http://www.autoforumz.com/eform.php?pc4475
Explain this. I have never heard of that before, where did you get that info from?
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http://www.autoforumz.com/Chrysler-98-concorde-starting-problems-ftopict130227.html
http://www.autoforumz.com/eform.php?pc4475
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
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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')
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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
Bill Putney wrote:

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jumped
with a

exhibit
and
restart
the
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
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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')
tim bur wrote:

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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).
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aarcuda69062 wrote:

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')
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Doesn't work that way.
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aarcuda69062 wrote:

Then how does it work?
Matt
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What are the necessary components to create a vapor lock?
Is heated fuel one of them?
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aarcuda69062 wrote:

It is the main one. Your point?
Matt
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aarcuda69062 wrote:

What?
Matt
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