Throttle loss problem, IAT and throttle body location?

[CRD-Joe]

I was using the Rotella T6 0W-40. Excellent soot control. K100 Diesel additive worked great for me as well.
Another big thing is that timing belt NEEDs to be done at 100k intervals or before. I've done them twice now on 2 different motors and trust when I say even at 100k miles it already seems borderline. These motors run great with proper maintenance. I even add a lift pump from Sasquatch parts, this took some strain off the high pressure pump, and I never had an issue with air in the system. As air with create more problems then u need, and shorten your hpfp life. Kawika can chirp in an add as well but the best things I did was:
Lift pump
Catch can (installed before egr delete)
Egr delete
Timing (full setup replacement with tstat)
Replaced valves with upgraded ones and tappets on top of the valve.
Replaced mechanical fan with electrical one
Samco intake hoses
Sasquatch intake hose
The next thing I was going to mess with was the transmission, as those are another weak point. However I ended up selling it before I did. You being across the pond from us are lucky as you have so many parts available around you for that motor. They even put it in the minivan with a 5spd lol.

 

[KJowner]

Looking at the pictures of your sensor it wasn't that dirty to start with, mine looked like a bit of coal but it was still working, if you have ruled out a wiring fault it's probably a faulty sensor.

 

[Pgy]

Looking at the pictures of your sensor it wasn't that dirty to start with, mine looked like a bit of coal but it was still working, if you have ruled out a wiring fault it's probably a faulty sensor.

Could it be the sensor I just cleaned? I should've just left it alone. Lesson leaned. There's no broken wires, there was none broken before and I only removed that sensor. Didn't touch anything else..

 

[KJowner]

Yes, you already had an issue so you needed to investigate, the symptoms you had initially could have been the boost sensor failing instead of being dirty & now its died completely. Without input from the boost pressure sensor the engine will run a default map without additional fuel to match the boost so performance will be awful.
Just another thought regarding poor performance, when was the fuel filter last changed? A clogged filter won't help....

 

[Pgy]

There is part of the harness that runs down the firewall that's really close to the egr system. That wire harness sometimes gets melted or pinched. Have you had your fuel gauge drop or oil light come on, water in fuel come on, an etc.?
Other things you can do is pull the pedal out, as it's only held in by 3 nuts and use an ohm meter to check resistance. An you can test the turbo boost module, and oil sensor (located on oil filter assembly)as well.

That's really helpful! I appreciate any suggestions! The fuel gage is functional, I even fueled the Jeep yesterday and it's reading just fine. Same for the temperature gauge etc. The car runs as it did before the sensor cleaning ( same sluggishness when accelerating) but other than that it's fine. I had the AC on, radio, lights, everything was functional. No resistance in the gas pedal, same response on the breaks, he's switching gears just fine as before.

Needless to say I freaked out, came home asap.
I didn't mention but when I removed/ placed back the map sensor I didn't disconnect the battery. Not sure if it matters but u forgot to do it.

Edited because I replied to the wrong post

 

[Pgy]

Yes, you already had an issue so you needed to investigate, the symptoms you had initially could have been the boost sensor failing instead of being dirty & now its died completely. Without input from the boost pressure sensor the engine will run a default map without additional fuel to match the boost so performance will be awful.
Just another thought regarding poor performance, when was the fuel filter last changed? A clogged filter won't help....

It could be that the MAP sensor just died. It was from 2008, never been cleaned or changed. Maybe because I messed with it I killed it
The fuel filter together with engine filter and oil was changed last October. I didn't drive that much because I was abroad alot.

I probably should order a new MAP sensor.

 

[Billwill]

That's really helpful! I appreciate any suggestions! The fuel gage is functional, I even fueled the Jeep yesterday and it's reading just fine. Same for the temperature gauge etc. The car runs as it did before the sensor cleaning ( same sluggishness when accelerating) but other than that it's fine. I had the AC on, radio, lights, everything was functional. No resistance in the gas pedal, same response on the breaks, he's switching gears just fine as before.

Needless to say I freaked out, came home asap.
I didn't mention but when I removed/ placed back the map sensor I didn't disconnect the battery. Not sure if it matters but u forgot to do it.

Edited because I replied to the wrong post

I have never disconnected the battery when removing the MAP Sensor.....as long as the ignition is Off then there is no issue! I still have the same MAP sensor on my 2002 Export 2.5 CRD....I have always been very careful when cleaning it!
I did have wiring issues from the MAP Sensor going to the ECM caused by damaged wiring from when my GF drove into a tree!
The early CDS like ours do not have a resistor built into the gas pedal...the pedal operates the resistor at the engine via a steel cable.

You can try re-plug the connector on the ECM which sits in front of the battery....this time first disconnect the battery!

I will look up the codes you posted...the trouble with using the "key" method to pull out codes is that you cannot easily erase them so that you can see if the fault is now fixed! I deliberately cause a code so that I then know any code that comes after my "marker" code is a new one....unless it is already in your list in which case it does not repeat itself!

P0520 Oil Pressure Sensor problem
P0235 Boost Pressure Sensor problem
P2120 ACC Pedal Position Sensor
P0651 Sensor supply 2 Voltage too high/low.

Download the Manuals for your 2003 KJ here:

www.colorado4wheel.com/manuals/Jeep/KJ/

 

[Pgy]

I have never disconnected the battery when removing the MAP Sensor.....as long as the ignition is Off then there is no issue! I still have the same MAP sensor on my 2002 Export 2.5 CRD....I have always been very careful when cleaning it!
I did have wiring issues from the MAP Sensor going to the ECM caused by damaged wiring from when my GF drove into a tree!
The early CDS like ours do not have a resistor built into the gas pedal...the pedal operates the resistor at the engine via a steel cable.

You can try re-plug the connector on the ECM which sits in front of the battery....this time first disconnect the battery!

I will look up the codes you posted...the trouble with using the "key" method to pull out codes is that you cannot easily erase them so that you can see if the fault is now fixed! I deliberately cause a code so that I then know any code that comes after my "marker" code is a new one....unless it is already in your list in which case it does not repeat itself!

P0520 Oil Pressure Sensor problem
P0235 Boost Pressure Sensor problem
P2120 ACC Pedal Position Sensor
P0651 Sensor supply 2 Voltage too high/low.

Download the Manuals for your 2003 KJ here:

www.colorado4wheel.com/manuals/Jeep/KJ/

Thank you! I downloaded the manuals!
I just don't understand why this happened only after I removed the MAP sensor.. Didn't have any of those codes before or the check engine light .. I was super careful and gently removed the sensor I barely moved any wires.
I guess I'll check the wires around the sensor again but I couldn't find any damage.

The problem is that I have no idea what those codes actually translate into when it comes to driving the car. The gas pedal seems fine, same as before.. I just hope I'm able to drive to the dealer so they can check without damaging anything else in the process.

Would it be safe to drive 10-15 mins ( city drive) to get there (With the current errors that I'm getting) ? Or is getting a platform to transport the car the only way?

 

[Billwill]

Should be safe to drive to the Dealers...provided they will assist you with a KJ problem!

Jeep have announced that they are no longer supporting the KJ series worldwide! Here in South Africa a few months ago I had the Dealers replace the Timing Belt on my 2002 Export 2.5 CRD....no problems other than I had to supply them with various Part Numbers for the belt!

A bit later I pulled in at the Dealer to get them to fix a major oil leak...Crankshaft Rear Rubber seals failing!

The receptionists were busy taking down my details when the Workshop Manager walked in and said that the KJ is no longer supported! No more parts to be supplied or service/repairs to be done as regards the KJ!

This applies world-wide but I think KJ Owners in the USA have several options to still get parts/service!

So at the moment I am only driving short distances and will probably scrap my Jeep soon.....best vehicle I have ever owned!

 

[Pgy]

Should be safe to drive to the Dealers...provided they will assist you with a KJ problem!

Jeep have announced that they are no longer supporting the KJ series worldwide! Here in South Africa a few months ago I had the Dealers replace the Timing Belt on my 2002 Export 2.5 CRD....no problems other than I had to supply them with various Part Numbers for the belt!

A bit later I pulled in at the Dealer to get them to fix a major oil leak...Crankshaft Rear Rubber seals failing!

The receptionists were busy taking down my details when the Workshop Manager walked in and said that the KJ is no longer supported! No more parts to be supplied or service/repairs to be done as regards the KJ!

This applies world-wide but I think KJ Owners in the USA have several options to still get parts/service!

So at the moment I am only driving short distances and will probably scrap my Jeep soon.....best vehicle I have ever owned!

Oh that's really bad news.. I still found parts for it, I doubt they will remove everything that's still on the market.
I also have a friend who's a mechanic specializing in Jeeps and he fixes any model, worked on mine before but he's abroad for a year so I can't go to him for this issue..

I'm not getting rid of the Jeep.. would be heartbreaking, as weird as that sounds. I'm sure there's aftermarket parts available in Europe & US..

 

[Billwill]

Oh that's really bad news.. I still found parts for it, I doubt they will remove everything that's still on the market.
I also have a friend who's a mechanic specializing in Jeeps and he fixes any model, worked on mine before but he's abroad for a year so I can't go to him for this issue..

I'm not getting rid of the Jeep.. would be heartbreaking, as weird as that sounds. I'm sure there's aftermarket parts available in Europe & US..

 

[Billwill]

If you do not come right try out the site Lost Jeeps site at www.lostjeeps.com

 

[Pgy]

Just a follow-up, I made it to the dealers, the MAP sensor was busted, I had already bought a replacement. They ran the tester but only the map sensor showed up and the same errors ( undervoltage/ over voltage because of the map sensor).
So the check engine light is gone but the throttle loss is still there..
I'm noticing it's happening at the 40mph step. On an incline it loses so much power that it just drops in speed considerably.

I really don't know what's wrong. Few years back, I had this exact issue and the mechanic cleaned some sensor and the throttle loss was fixed.
Only problem is I don't remember which one, and I don't have any receipts for the repairs.. I just remember it was something straight and metallic and caked in oil / something black.. He showed a picture with the before&after.

 

[KJowner]

That's the only sensor I can think of is the MAP, early CRDs don't have anything else.
Annoying that didn't sort it out, its the usual culprit for power loss and poor running. You did buy a real Bosch one didn't you??

Moving on it sounds like it may be a lack of fuel delivery. Has the fuel filter been replaced? Initially try a good quality replacement and ensure that there isn't an old o ring stuck in the housing. I assume you have the early white aluminium filter housing? I use Delphi HDF641 filters on mine. If you have the later black plastic filter assemble then they are known to leak & melt around the heater.
Inspect and replace any suspect looking hoses in the fuel system as well.
If all is well with the filter it would be worth getting a garage to check fuel pressure on the rail during fault conditions & perform a leak off test on the injectors.

The other things that spring to mind are a stuck open EGR valve or dragging brakes, but I expect you would have noticed if the brakes were binding.

 

[Pgy]

That's the only sensor I can think of is the MAP, early CRDs don't have anything else.
Annoying that didn't sort it out, its the usual culprit for power loss and poor running. You did buy a real Bosch one didn't you??

Moving on it sounds like it may be a lack of fuel delivery. Has the fuel filter been replaced? Initially try a good quality replacement and ensure that there isn't an old o ring stuck in the housing. I assume you have the early white aluminium filter housing? I use Delphi HDF641 filters on mine. If you have the later black plastic filter assemble then they are known to leak & melt around the heater.
Inspect and replace any suspect looking hoses in the fuel system as well.
If all is well with the filter it would be worth getting a garage to check fuel pressure on the rail during fault conditions & perform a leak off test on the injectors.

The other things that spring to mind are a stuck open EGR valve or dragging brakes, but I expect you would have noticed if the brakes were binding.

I bought a Bosch MAP sensor, they also checked for any faulty but there wasn't any.

As it happens my handbrake got stuck the other day while I was on the highway and I only noticed when I got home because of the smell. I didn't drive long, less than 4 miles I'd say but the weird thing is I didn't notice any difference..
I took it to a tire shop and they sprayed some WD40, it's fine now but I'll change the handbrake cables and plates soon anyway.
I have new brake disks and brake plates, less than 4 months old and this incident, luckily didn't cause any damage, other than the smell..
I don't think it's related, but sure was a wire coincidence. I guess it's because I was away 2 weeks and left the handbrake on.

Even so, I still have the same power loss issue. The worst is uphill because it's just not pulling at all even though I'm flooring it. The rpm just drops slowly and so does the speed until it shifts in a lower gear then it gets a massive boost and shoots off..

I wish cars could talk..

Edited to add: fuel filter was changed 9 months or so ago, i have a Mann.

 

[KJowner]

Definitely worth investigating the fuel filter, it sounds like a lack of fuel or an air leak in the fuel system to me.

 

[Pgy]

Definitely worth investigating the fuel filter, it sounds like a lack of fuel or an air leak in the fuel system to me.

I will check it this weekend. What could cause an air leak in the fuel system? Sorry if it's a stupid question but I don't know much about the air intake and all that..

 

[KJowner]

The KJ fuel system is a poor design, there is no lift pump so the high pressure pump on the engine has to suck fuel all the way from the tank, there are several potential leak points along the way, especially at the fuel filter. the best solution is to fit a lift pump in the tank, a job I have planned for mine, another option is a remote lift pump elsewhere. If you search on here and on lost jeeps you will find lots of posts about it.

Fuel starvation will give you the symptoms you have, a blocked filter or air leak into the fuel.

You don't have any fault codes now do you?

After that I would look at the rest of the fuel system, a friend garage may help you by putting a gage on the fuel rail so you can see what's happening under load, you may have a problem with the pump pressure controller or the injection pump itself, but start with the simple faults first.

 

[Pgy]

The KJ fuel system is a poor design, there is no lift pump so the high pressure pump on the engine has to suck fuel all the way from the tank, there are several potential leak points along the way, especially at the fuel filter. the best solution is to fit a lift pump in the tank, a job I have planned for mine, another option is a remote lift pump elsewhere. If you search on here and on lost jeeps you will find lots of posts about it.

Fuel starvation will give you the symptoms you have, a blocked filter or air leak into the fuel.

You don't have any fault codes now do you?

After that I would look at the rest of the fuel system, a friend garage may help you by putting a gage on the fuel rail so you can see what's happening under load, you may have a problem with the pump pressure controller or the injection pump itself, but start with the simple faults first.

I see, I had no idea and the mechanics didn't really take the time to explain anything.

No error codes anymore. But I'll go and ask them to check for possible fuel starvation. They probably know what to do, but I like to at least have a basic idea beforehand, so thank you for the detailed reply!

I think it's some issue with the fuel injector, maybe the previous time I had this issue, they cleaned it and it worked again. It was caked in but no one said I should replace anything.
Different dealership now, so we'll see what these say..

 

[turblediesel]

The in-tank pump is the best solution. The fuel line fittings are designed to seal under internal pressure. They draw air in when under suction from the CP3 pump or an inline pump.