P0174 has become a recurring event on this 2001 xk8 wit 150k on the clock.


On start up the engine feels rough, settling after a few minutes and purring and running strong the rest of the day.


I checked for vacuum leaks with soap water, break cleaner and I eventually smoked the engine. No leaks.


Switched the top Oxygen sensors at the engine bay. Engine bucked and fuel trims went crazy.


Returned to original setup and she settled down with both short and long fuel trims normal. Light went out. Ran good for two days.


Yesterday light came back after start up, first in pending codes and at a later switch cycle it showed on the dashboard.


No P0171.


I am lost here. Before replacing the Oxygen sensor in bank 2 what else could I do?


Bad Cat?

 

Has the fuel filter or fuel pump been check for blockage or low fuel pressure. With 150K on them they're a likely suspect for you problem and are listed as major contributor to P0174. Also possible fuel injector blockage.


Of course there are the usual electrical bug-a-boos but I'd check the mechanical aspects first so get a fuel pressure test gauge and check pressure after the pump and then after the filter.

 

A P0174 is a lean indication for only bank “B” because you do not have a P0171 lean for “A” bank you could for the moment rule out a vacuum leak, MAFS, Fuel Filter, Fuel Pump, o2 sensor and a few other things for now. Did you switch side to side or top to bottom o2’s? Switching the o2 sensors without doing a hard reset could the shacking.
I would recommend cleaning your throttle body MAFS and use BG44K fuel additive. Chances are that you have a fuel presentation problem related to bank “B” only and the BG44K could clear the problem.

I would do this first and then we can look further into the problem if it still exists. Remember any time you unplug anything on your car disconnect the battery and do a hard reset when you are done.

 

So this may be a dumb question...but...

When referring to "bank A" and "bank B" for codes such as this or when checking fuel trims, which is a "A" and which is "B"?

Nick

 

Bank #1 is A
Bank #2 is B

 

Air intake leak between MAF sensor and throttle
Fuel filter system blockage
Fuel injector blockage
Fuel pressure regulator failure (low fuel pressure)
Low fuel pump output
H02S harness wiring fault
Exhaust leak (before catalyst)
ECM receiving incorrect signal from one or more of the following sensors - ECT, MAF,IAT, TP

 

Thank you Gus
Fuel pump and filter have been recently changed. I to believe that any shared system at fault would generate a code for both sides. While MAFS and TB fall into this category, it never hurts to have them clean. Dirty injector or injector seal leak is where I am pointing to.
Will try to source the BG44K, I did use some techron with the last gas tank.

Is there a procedure for testing the fuel rail and injectors while in the car?
Or do they need to be cleaned individually?

 

With the code will be freeze frame data. It's worth checking it for clues such as what the trims were on both banks at the time in case both suddenly went out. If so, can be so-and-so reasons, if not then other reasons.

Will also have speed/rpm etc which can be helpful.

 

Jagv8
I have set up a subset of pid's to read live data for short and long fuel trims and temp on my Actron scanner.
I havent the foggiest idea how to set for freeze frame when the code is triggered.
Any help welcome

 

"Is there a procedure for testing the fuel rail and injectors while in the car?
Or do they need to be cleaned individually? "

I know you're asking about the fuel rail and injectors but don't overlook the fuel pressure regulator as it's right up towards the back of your engine on top near the throttle body and it's easy to test. And yes it would seem that a fuel pressure regulator failure should trigger both sides but the DTC charts and the trouble descriptions leave that open for debate.

I can't find any mention of an on car test for either the fuel rail or the injectors as everything I can find in both JTIS and the individual manual referencing a supercharged 4.0 makes no mention of such a test for either component.

There is available as I recall a fuel injector cleaning solution in a pressurized form that I think could be hooked up to the fuel rail and then run through the rail on that side and through the injectors. It's a more concentrated form and more direct than you'd get with the use of a fuel additive. That way you could at least know that the injectors should be clean as well as the fuel rail and you do so without the engine running or any of those pieces off the car.


D1 : CHECK FOR FUEL PRESSURE CHANGE WHEN THE REGULATOR IS DISCONNECTED
1. Connect a fuel pressure gauge set, <<310-00>>
2. Start the engine.
3. Note the fuel pressure reading with the fuel pressure regulator vacuum hose connected.
4. Disconnect the fuel pressure regulator vacuum hose
5. Note the new reading.
Does the fuel pressure increase when the hose is disconnected?
-> Yes
Check for DTCs. Carry out pinpoint tests indicated.
-> No INSTALL a new fuel pressure regulator. TEST the system for normal operation.
17

 

Since you are getting only a "lean bank" code, I would suspect that the injectors are fine. If one or more were problematic, you would likely get misfire codes for that cylinder. However, you can test each injector for flow, and for leakage with an OTC injector driver. When connected to the injector, you would key on to pressurize the rail (viewing the pressure on an attached gauge), then press the button on the OTC tool which drives the injector a precise amount, and when done you record or compare the amount of fuel (in psi) used on that cycle. They should all be the same, or darned close. You could also just unplug each injector one by one with the engine running to compare the amount of "drop" in engine speed just to get a roulgh idea of whether or not a particular cylinder may be problematic over another. The fact that it momentarily runs rough when cold started still leads me to a vacuum leak (like manifold seals). Or, a leak in the pressure regulator which would allow extra fuel to enter the system as it slowly bleeds down when sitting. But that would create a temporarily rich condition. Easy enough to check. Pull the hose off the regulator and look for wetness inside. May be several issues here.

 

I know of no real procedure to check your fuel injectors with the exception of removing them and have them tested and cleaned by someone that does that kind of work. I have used t stethoscope to listen to each injector as the car was running. What you should dear is a distinctive ping when you hear a thud that would be an indicator to me that it needs work. My first action is to get BG44K I have used other products but none match the performance of BK44K it is used by Jaguar and other known dealerships and reputable repair shops you will not find it at Autozone or Advance Auto. If I still suspect that the injectors need work I remove them and send them to be cleaned or replaced.

 

First,our computers are dumb,you are running lean on both banks.

Here is how I would start.Your car is running rough, so you have misfiring with no misfire codes,typical on these ecms a lot.

Replace all 8 spark plugs,clean your maf sensor reader(the fine silver colored wire(s) that reads the air in the intake tube) using maf cleaner spray.

Remove the coil pack boots, using the same cleaner clean their springs off as well and oil out the boots.
Replace you air filter. Rest the codes, hit the highway. $40 bucks in parts

Ohm all 8 injectors using a digital multi meter, they should ohm the same. After this, you should be fine.

 

Injectors look unlikely as then you'd expect rich codes.

Might be a damaged cat.

What are fuel trims with hot engine, parked, at idle & 2500rpm? If they don't go from fairly +ve to much nearer zero you're not looking for an air leak.

 

Are we talking about a P0174 code?

Link to codes http://www.jagrepair.com/images/Auto...J27%201999.pdf

Note a clogged or poor operating fuel injector is listed

 

Wow who need to go to Automotive school when we have the Forum.

I gave the Maf a good drenching with Maf cleaner. Several shots.

Read the fuel trims and both banks long and short trims are way off to the lean side while driving. Sometimes hitting +20 so something is definitely wrong.

One has to be carefull what one wishes for with these Jags, now P0171 joined the party.

Now we are back to square one. Both banks are problematic so vacuum leak is back in the picture so is fuel.

So option 1. Fuel delivery problem.
Will check fuel pressure at the rail and will test fuel pressure regulator.
will Ohm test injectors will replace plugs and clean coil plugs.

option 2. Bad MAF
Will replace with known good MAF and recheck fuel trims.

option 3. Air leak
Will resmoke the system

Also will follow other maintenance suggestions.

Could not find the Berryman localy, wil order from Amazon. Used Rislone fuel treatment on half a tank of gas. Will report any changes.

Thanks again for the help.

Jm

 

I am going to give you a little reading material related to Fuel Trims it should help with understanding what is taking place.

Link JagRepair.com - Jaguar Repair Information Resource

I would also like for you to read this thread.

Link Wow BG 44K - Jaguar Forums - Jaguar Enthusiasts Forum

For codes P0171 & P0174

Link http://www.jagrepair.com/images/Auto...otos/P0171.pdf

 

thank you Gus reading!

Well, replaced Maf with a known working unit.... no change.

Dove under the coil covers, what a shock. Brand new coils!

slight cracking of wire insulation. I have a feeling we will be replacing or rebuilding a lot of theese in the future.

And under the coils brand new E3 spark plugs. I've been wondering about these for a while and here they are.
Could they be causing the problem? Not the right kind? To hot, to cold?

Additional finds, cracked air filter box. crinckled air filter not seating properly at the top rubber seal. Being before the Maf it should not be affecting the reading? right?
Dirty throttle body, ring around the collar and butterfly hinge. Cleaned!

For the sake of Jaguar Scientific observation I replaced the E3 spark plugs on bank 2 with NGK and left the E3 on bank 1.

 

Hi there i'm interested to know if you have ever solved your problem?

I'm suffering from the same problem although i had a broken breather hose (which i changed along with IMT o ring) but my car still gives me P0174 and goes into limp mode after 10 minutes of driving, it also has some weird coughing noise after i depress the gas pedal.

I drive a 2005 xtype 2.1 petrol engine by the way...

 

You really want to be in the X-Type forum.

Then follow what those guys do when they have that. (Forum Search.)