Hello guys. I’ve been chasing p0171-174 codes for over a year. Getting to the end of my rope. Changed out o2 sensors. Intake manifolds upper and lower. Code just keeps coming back. My inspection is due this month and in NY you fail automatically if the check engine light is on. Or if u erased it and the system shows readiness monitors are not in order. Also my heat is not blowing out hot. Fan works. Blows like crazy. Changing the flow from feet to defroster and such seems to be working. Get the car warmed up and turn heat temp all the way up. Comes out hot for a few seconds then lukewarm at best. Any advice is appreciated. Getting sick of throwing money at this car and still having the same issues b

 

NYC, I am assuming you have also changed out the "big 3" for the vacuum leak. You mentioned you did the upper and lower intake o-rings. This is where I would then tell you to look on the back of the intake near where the nut hides that you have to remove to get teh intake off. There is a vacuum line there as I recall and you can follow that to under the intake. that was a plastic tube and with age and heat, it can become brittle and crack, leading to your vacuum leak. I want to say there is a second tube, but I do not recall where it ran to/from. 1 tube should be green and one orange as I recall. But you can find them together under the throttle body

After that, I would tell you to find a good cigar (if you don't smoke, find a friend who does and tell them the deal, you will buy the cigar, he just has to blow the smoke where you say). Light the cigar and then open the hood of the car with the motor cold. Make sure the heat-A/C is turned off to ensure the engine fan will not blow. From there, start up the car and blow the smoke into the engine bay so it just kind of floats around in there. Be watching the smoke as you blow it into different places. What you are looking for is the smoke to be going in one general direction and then make a sudden change in direction and speed. Where it runs to is where the vacuum leak is. From there, once you know where the vacuum leak is, you can determine a corrective action.

Now, for your heat issue, it sounds like you have a plugged heater core. To fix this, you are going to need to use a water hammer. I know what you are thinking, great, a new tool I need to buy. Not so fast, what you need is an air compressor, a spray tool, and a bit of water (this is your water hammer). What you will need to do is to find the 2 lines going to the heater core. Disconnect the hoses at a fairly convenient spot as you are going to need to put the air tool on the hose. This may involve draining some coolant from the car. What you are going to do is see if you can determine which way the coolant flows. If you can do this, go to the outlet side and using the air tool, squeeze the hose around the tool and give it a quick blast of air. You want the air/coolant kind of jar the plug (like a hammer would to something stuck, tada, a water hammer). Give it a few blasts. Then move to the other hose and repeat. If you think you have blown the coolant from the line, pour a bit of water into the hose and then give it another blast. Hopefully after a few hits with the air, whatever is stuck in the heater core will come free and shoot out the hose. Keep going back and forth and eventually it should kick out the plug. If not, then you are most likely looking at a new heater core which is goign to mean removing most of the dash from your car. I am not sure how much pressure the hoses and heater core can take, but you should be able to give a 1-2 second blast of air.

 

Thx Thermo. I’ve also read that the heat being hot for a few seconds then getting cooler can be the blend door that controls the heat and ac sticking open. They said you can access the 3 blend doors through the glove compartment. Any info on this or how to get the glove compartment out will be helpful. Thx

 

NYC, to rule out the damper and the computer doing funny things, put the controller in manual mode. That should force the dampers to a certain point and cause them to be locked there. If things are still moving, then you have an actuator problem

As for removing the glove box, I want to say it was a series of screws at the bottom. You open the glovebox, then you have to flex a stopper on the "left"(?) side to allow the glove box door to go all the way open. This will expose the piano hinge holding the door in place. From there, you can remove the screws and with the box out of the way, you can see all the actuators there on the passenger side of the center column.

 

Hello guys. Ive noticed something today when I hooked up the code reader to my car. It’s saying a O2 sensor as failing the O2 sensor test. It can only read the bank 1 sensors which I don’t understand why. But here’s a few pictures of what it’s saying. I don’t know if this may be causing my P0171-P0174 codes. Getting very frustrated and don’t wanna just keep throwing money for parts. I need this fixed or I can’t pass my inspection this month. Thx for any help.

 

Also my fuel mileage says 19.8 mpg

 

Tried to do a data stream and freeze frame with the code reader have the pictures of it. Also noticed that at 3000 rpm’s the car bucked a little and seemed like it didn’t want to climb in rpm’s.

 

 

NYC, if your check engine light is on, you may be RPM limited to 3000 RPM. So, what happens is when you try to go above 3000 RPM, the ECU cuts off fuel to the engine, causing the car to lose power and buck like you are seeing.

I am taking a step back and looking at bit more at a bigger picture. You seem to be having numerous issues all at the same time. When ever the X-Type starts having a number of issues, it turns out to be electrical. This is where I would tell you to do my cable check first to see if your battery cables are good and not causing a low voltage condition in the car (this can raise a lot of hell). Then next I would get a load test done on the battery (should be above 75% capacity). If all that checks out good, then we have multiple issues and need to deal with each one individually.

The heat issue I think you can rule it out to either an actuator issue or a plugged heater core by simply removing the glove box to gain access to the 3 actuators on the side of the air box. You can drive the temp of the car up and down with the A/C controls and you should see 1 actuator moving to control the blend door. You want to watch the big part of the actuator move, but also watch the center shaft. There have been instances where the actuator has moved, but the center shaft does not. people ended up either replacing the actuator or gluing the shaft to the actuator.

 

Thx. But my biggest problem right now is these lean codes. And with the engine light on I’m ****ed for getting inspection at the end of this month. I’m pretty much ready to junk this car. Shane cause it runs fine gets good gas mileage. And my old mechanic killed himself trying to solve the p0174 code a year ago. Now I’m getting p0171 and p0174. The new mechanic just wants to change out parts that might be the problem. Which is expensive and in the end. I have the same problem

 

Brand new battery 2021. Use the car at least every 3 days

 

If parked - probably rev limiter.

It's bad for the car, esp. trans, to rev hard parked.

Stop clearing codes. Always clears monitors. Prevents smog pass.

Forget heat problem, just go for lean issues / smog pass.

Do the fuel trims drop a lot when revved or not? That tells you whether it's an air leak or not.

 

Thx guys. Jag V8. Rpm’s go over 3000 when parked. Only happens while driving. Can you please tell me step by step how to check the fuel trims I’m not very knowledgeable with the code reader. Gas mileage is good. Car starts right up and runs good. It’s these codes that are screwing me. In NY with a check engine light on. It’s an automatic fail for inspection. They won’t even put the car on the inspection machine. Any help is greatly appreciated. Losing my mind with this !!

 

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