Jeepers. Tech Help please

BAHA · Post by **BAHA** » Sun Feb 08, 2015 2:24 am

Facing a weird behavior on 5.7 grand of almost engine shutting down, and did went off couple of times when hitting the break to a stop. If only slowing down not to a full stop she's fine and keep going. But when going to a full stop- like of traffic light- rpm goes down to almost -and some times- engine his off!!
My first suspect was the spark plugs ( but no misfire codes) second is Pcv valve ,
Could it be something serious need to look at before jumping to surgeries ?
Any ideas, suggestions.

Thanks

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Aidy · Post by **Aidy** » Sun Feb 08, 2015 5:19 am

Am pretty much sure it could also be the crank position sensor, but you have to go to a proper jeep understanding garage to make sure!!

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Xof · Post by **Xof** » Sun Feb 08, 2015 7:06 am

got this... easy fix: change the battery!

SCORPIO · Post by **SCORPIO** » Sun Feb 08, 2015 8:54 am

did you feel any strange behavior in your gear ?

may be when shifting down at almost stop, your gear should release
the clutch Automatically, if this is not happening this might push
your engine to cut of, its like stopping a manual car using the break
without stepping on the clutch

Jalal

Dune Rider · Post by **Dune Rider** » Sun Feb 08, 2015 9:48 am

jeep dealer

BAHA · Post by **BAHA** » Sun Feb 08, 2015 11:25 am

Battery and clutch are unlikely to be the reason for it starts perfectly and no gear behavior or such.
Have a stored code p0404 and some googling lead to another suspect might be causing this. The erg valve.

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Xof · Post by **Xof** » Sun Feb 08, 2015 11:41 am

BAHA wrote:Battery and clutch are unlikely to be the reason for it starts perfectly and no gear behavior or such.

i told you baha, it happened to me... idle was going to off... but car was starting... I just changed the battery, and solved. So, when was the last time you actually changed your battery.

DesertDawg · Post by **DesertDawg** » Sun Feb 08, 2015 1:02 pm

Does the car idle properly?

P0404 - Exhaust Gas Recirculation Circuit Range/Performance

The EGR (Exhaust Gas Recirculation) system's purpose is to redirect exhaust gas back into the cylinders. Since exhaust gas is inert, it displaces oxygen and fuel, thereby lowering cylinder temps, which, in turn, lowers oxides of nitrogen emissions. For that reason it needs to be carefully metered into the cylinders (via the EGR valve) so as not to adversely affect the engine's performance. (Too much EGR and the engine won't idle).

DesertDawg · Post by **DesertDawg** » Sun Feb 08, 2015 1:08 pm

but car was starting... I just changed the battery, and solved

My gut feeling is that if the car can consistently start i.e. battery is able to supply the 100 amps to crank engine, then it is not a battery issue.

The code is the clue P0404 - probably EGR stuck and exhaust feeding back into inlet. Does not matter while driving because orifices too small to alter mixture, but while idling or deceleration - different matter.

Try blocking feed from EGR to inlet (clamp tube). If ok, then replace EGR and/or inspect pipes to from for leaks.

Dave

DesertDawg · Post by **DesertDawg** » Sun Feb 08, 2015 1:14 pm

but car was starting... I just changed the battery, and solved

Not saying this is why Xof resolved problem....but changing battery would have side effect of resetting Engine Management System.

BAHA · Post by **BAHA** » Sun Feb 08, 2015 2:48 pm

DesertDawg wrote:Does the car idle properly?

P0404 - Exhaust Gas Recirculation Circuit Range/Performance

The EGR (Exhaust Gas Recirculation) system's purpose is to redirect exhaust gas back into the cylinders. Since exhaust gas is inert, it displaces oxygen and fuel, thereby lowering cylinder temps, which, in turn, lowers oxides of nitrogen emissions. For that reason it needs to be carefully metered into the cylinders (via the EGR valve) so as not to adversely affect the engine's performance. (Too much EGR and the engine won't idle).

It does idle ok,
when slowing down from a normal acceleration, rpm will go down almost to 0 but may not stall.
But when accelerating fast then quick back to 0 it will shut off.

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DesertDawg · Post by **DesertDawg** » Sun Feb 08, 2015 3:35 pm

Mr Google says a stuck open EGR causes a stall on deceleration.

Disconnect EGR to inlet manifold line at EGR and plug line to inlet manifold. Drive car and see if issue persists.

Dave

BAHA · Post by **BAHA** » Sun Feb 08, 2015 6:43 pm

DesertDawg wrote:Mr Google says a stuck open EGR causes a stall on deceleration.

Disconnect EGR to inlet manifold line at EGR and plug line to inlet manifold. Drive car and see if issue persists.

Dave

It turned out to be the issue
Spark plugs also seriously required replacement ( all bloody 16 of them

)
For now problem solved but got new code P0403 and according to mr Google is catalyst thing I think it can be ignored if no drive problems showed up.

Many thanks Dave and all discussion participants.

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DesertDawg · Post by **DesertDawg** » Sun Feb 08, 2015 8:26 pm

A partially blocked cat increases back pressure and forces more exhaust gas through EGR into inlet.

Get rid of it.

Dave

BAHA · Post by **BAHA** » Sun Feb 08, 2015 8:47 pm

DesertDawg wrote:A partially blocked cat increases back pressure and forces more exhaust gas through EGR into inlet.

Get rid of it.

Dave

If the catalyst ??

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