Severe Loss of Power

BobFarley · **Posted:** Fri Mar 05, 2010 9:51 pm

Jeep is severely lacking power at take off and will barely go over 60 with pedal mashed...any little incline and the speed drops dramatically due to the lack of power. I thought at first it might be the CAC hose on the hot side. I replaced the CAC cold side hose about 9 months ago and it had a similar symptoms at that time. The difference this time is it seems hard to start and doesn't seem to want to start without a little pedal.

i'm going to tear into it and hope it is only the CAC hose and not something more severe like a clogged injector or burnt fuel pump. I was running low on fuel and stopped to fill up then when I started again it was lacking power and sounded like it was missing on a cylinder. Probably going to change the fuel filter while I'm at it.

Any suggestions as to what the problem might be would be helpful. I'm pretty mechanically inclined and prefer to trouble shoot the problem myself rather than take it to the dealer to have them scratch their heads because they've never even seen a deisel jeep.

Wish me luck!!

racertracer · **Posted:** Fri Mar 05, 2010 10:16 pm

Sounds like a clogged fuel filter...... how many miles do you have on your fuel filter. Could also be air in the lines, bleed the line.

Larry R. · **Joined:** Sun Jan 21, 2007 1:35 am **Posts:** 92

Dito on fuel filter, also check to make sure the intake air temp. sensor is plugged in. Mine come unplugged and caused the same problem.

geordi · **Posted:** Sat Mar 06, 2010 12:26 am

You are in limp mode, look for a sensor to be either unplugged or buggered. The Mercedes Logo sensor (which is NOT an intake air temperature sensor) on the airbox is a likely suspect, it comes unplugged easily and puts you into limp as soon as it does.

BobFarley · **Posted:** Sat Mar 06, 2010 12:39 am

Fixed...it was the fuel filter after all. I did take a look at the CAC hose also and the hot side is definately in need of replacement. I think that will happen sooner rather than later.

Thanks of all the help!

Larry R. · **Joined:** Sun Jan 21, 2007 1:35 am **Posts:** 92

Geordi, What is the sensor on the side of the air box for? not the mass sensor, this one is on the engine side of the air box. I thought it was the air inlet temp sensor? Thanks

geordi · **Posted:** Sat Mar 06, 2010 11:23 am

It is another MAP sensor, this one happens to be getting used to measure the ambient air pressure, rather than the boosted pressure of the main MAP on the back of the intake.

The problem is... When it goes, the ECU no longer trusts its other sensors, and your power goes bye bye.

linewarbr · **Posted:** Mon Mar 08, 2010 12:04 pm

As I understand it that is the Intake Air Pressure sensor, not Temperature. (Although I'm sure it measures temperature as well, to make sure you're not driving on the surface of the sun) A lot of members have recently had trouble with that one little sensor. It is easy to dislodge when you change your air filter.

Luisboost · **Posted:** Mon Mar 08, 2010 8:57 pm

I had this similar problem, (lack of power), but intermittent, the curious thing is that in the morning (or when is cold) when I start and use it, it feels strong, then after I turn it off during the day, the next time that I use it, it feels like a pig, uphill something barely gets 40 mph!!!. OK, the fuel filter is relatively new (and remember is an intermittent problem), also I check the connector of the sensor of the airbox, and I have an external fuel pump. My only ideas were maybe the intake air pressure sensor damaged (where I can buy it??), and I'm planning to remove the butterfly of the intake (maybe the ECM close it partially to regulate the power???), because in occasions my scanners read a low boost warning, and yes I check the turbo and is in good condition. Any help would be appreciate.
Luisboost.

PD Also I forgot that my scanner also read low volt circuit in all my 4 Gow plugs, but the Jeep start smoothly and easy. The other Map Sensor (top of the engine) is brand new and I have the EGR sensor disconnected.

dkenny · **Posted:** Tue Mar 09, 2010 8:16 pm

my wife jeep is having almost the same problem.

things checked changed so far
lift pump. it fine. spare pump also fine. hold 12 psi on the output of the filter
new filter(Racor 2 micron, R25S)..less than 5 miles
fuel 1/2 tank.
cac hoses removed and checked. next is to pressure test the intercooler. would 10-20psi be enough?
intake box senor plugged in and looks good. does anyone know how to test these? what voltage should be read on the wire?
I would think air filter but the problem started when my floored it to pass someone..

at the moment it start ok.
idles fine. revs in neutral fine
goes ok unless I try accelerate fast..then it dies..

the only code I've seen is P0093.

with the scanner software that I have it reads the fuel pressure. I think its the rail pressure. does this pressure vary much or should it be fairly constant. if I remember correctly at idle it was around 30,000kPA but varied from 20 to 40. is this normal?

thanks for the help
-dkenny

Joe Romas · **Posted:** Thu Mar 11, 2010 9:20 pm

Luisboost wrote:

Also I forgot that my scanner also read low volt circuit in all my 4 Gow plugs, but the Jeep start smoothly and easy.

You should never need glow plugs in Porta Rico.
Unless our "Global Warming" goes totally haywire and it snows for you :-)r

Severe Loss of Power

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