[QUOTE=sirwilliam706;11248597im just not understanding why i am not getting any trouble codes[/QUOTE]
The PCM does not monitor the following circuits,
systems and conditions that could have malfunctions
causing driveability problems. The PCM might not
store diagnostic trouble codes for these conditions.
However, problems with these systems may cause the
PCM to store diagnostic trouble codes for other systems
or components. For example, a fuel pressure
problem will not register a fault directly, but could
cause a rich/lean condition or misfire. This could
cause the PCM to store an oxygen sensor or misfire
diagnostic trouble code
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor or fuel system diagnostic
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables.
The PCM cannot detect uneven, low, or high engine
The PCM cannot detect a plugged, restricted or
leaking exhaust system, although it may set a fuel
FUEL INJECTOR MECHANICAL
The PCM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injector
is installed. However, these could result in a rich or
lean condition causing the PCM to store a diagnostic
trouble code for either misfire, an oxygen sensor, or
the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen
content when the system is in closed loop, it cannot
determine excessive oil consumption.
THROTTLE BODY AIR FLOW
The PCM cannot detect a clogged or restricted air
cleaner inlet or filter element.
The PCM cannot detect leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices. However, these could cause the PCM
to store a MAP sensor diagnostic trouble code and
cause a high idle condition.
PCM SYSTEM GROUND
The PCM cannot determine a poor system ground.
However, one or more diagnostic trouble codes may
be generated as a result of this condition. The module
should be mounted to the body at all times, also
PCM CONNECTOR ENGAGEMENT
The PCM may not be able to determine spread or
damaged connector pins. However, it might store
diagnostic trouble codes as a result of spread connector
Okay did all the tests i could and they all seemed to be working properly i am holding about 1000 rpms when cold and 700 rpms when hot at idle no problems yet but havent given the real test of long distance driving. i guess i will do it early in the so if is messes up i can just come back that night and be able to drive it home. This is still very mind boggling its like the electrical has a ghost because of the rareness of the incidents it will start to hesitate but if i let off the gas pedal and just let it idle i runs fine as soon as i give it gas it wants to die but to date has never shut off on me just loses all hp and seems to act like its missing. I still have to wait on it too start acting up to do the same tests to see if the results are different but hopefully the problem is gone but doubt it
If that were my truck I'd be doing everything in my power to force the random failure into a full time failure. If it's cured by the time you get it home the only answer is to throw parts at it.
Ever have a fuel pump crap out? When you cut fuel pressure in half you have no throttle response and are often top speed limited to about 30 with a lot of pedal feathering. Sometimes they don't die all at once. If something's flopping around like a pump seal or regulator seal, you'll get this.
Might wanna take off for some low traffic roads with a charged cell phone and a fuel pressure gauge. So when it acts up you can learn something on the spot.
Does this truck have the skidplate package? If not, when it acts up whomp the tank bottom with a rubber mallet, see if symptoms change.
250 is not an acceptable idle speed. First mark on the tach is 500. 600-1000 is normal for automotive gas engines depending on whether it's hot or cold or in gear. 700 is pretty normal.
I have to admit that 250 on my tach is rather low, but I never gave it much credence as to whether it was right or wrong since it engine runs and idles good and the ac stays cold in the summer.
In the olden days of of points and condensers, stock engines were tuned to 550 rpm with a vacuum between 18 to 20 psi. If the idle could not be brought down to at least 650 a vacuum leak was usually suspected along with fuel trims and advance settings.
So with that said I checked for what Chrysler would consider normal and the only thing I found was in reference to a DRB 3 troubleshooting procedure for the throttle body, air flow test. The DRB will look for and adjust the rpms to between 600 and 900 rpm and anything else was not acceptable.
1000 rpm would be out of range also.
Having an automatic transmission grinding at 1k in stop an go traffic wouldn't be good thing for the tranny.
Personally, I think their acceptance range is a little high, but that just me.
Okay went out driving today run about 100 miles with no problems im thinking great so i head home feeling pretty good when it started again im starting to notice that it happens more when the tank is around a quarter tank. How much does the fuel have to do with cooling the pump and could overheating of the pump make it start to act haywire?
Chrysler recommends that the tank have at lest 1/4 of a tank to keep the pump cool. Does it cause it to over heat with less? I would say so.
I've have ran my tank many many times with less and so far it's still working with 215k on it. A pressure test when cool and then when it's warm would probably give you a better answer than a guess from one of our members.
You should get 36-39 psi in a good working pump in your year Jeep.
cant really pin point its between the coil, fuel pump, fuel pressure regulator, iac or tps i just changed them all and i also cleaned the fuel rail and threw so seafoam at it. Its really too early to tell if it fixed it but i know the motor can tell it has new parts. i will update if any changes i know any help to this problem will be to the good. Once again thanks to everyone involved with this great help i think im going to be on here pretty regularly like i said forums like these have helped me figure out problems on so many things without the expensive labor cost.
If it was the fuel pump/regulator a lot of times they'll pick up noticeable power even though prior pressure was within range. You'd have to strap the gauge to the windshield and road test under load to spot a failing pump. In the driveway all a pressure gauge spots is a fully failed pump