My 2005 STR is at 81K miles. I have reset the codes 3 different times and not right away but within several days I get a check engine light and it's always 0191. Fuel rail pressure sensor.

This code can be the sensor or a fuel pump problem? Can be high or low fuel pressure. The car now is loosing power but not consistent. At high speeds it does seem to run out of fuel but other times pulls OK. Today at low speeds it was stumbling and not responding to the gas pedal at all but then picked up and drove OK.

Brutal any idea's?? I hate to change both fuel pumps because of the expense and I can't see both pumps going bad at once. Maybe a REM problem?

I changed the fuel filter yesterday and it only had 5K miles on it. Fuel that drained out of it looked fine.

May be a dealer fix on this one?
.
.
.

 

I hope a tech's interested

Very possibly WDS/IDS/SDD can exercise the fuel pumps via the REM / fuel pump 2 module and report.

From codes PDF it doesn't look likely to be the REM. IP sensor or wiring/etc would perhaps be the cheap things to check/change.

Ahh... what does the freeze frame data show?

 

I don't have a code reader. Just use the auto parts store service. So I can't get any freeze frame data.

I am afraid it will take the WDS to avoid just throwing parts at it.
.
.
.

 

A good enough OBD tool that can report freeze frame costs $10-15.

 

Yes you are right. I could use it for that price!
.
.
.

 

Thinking about replacing the Fuel Rail Pressure Sensor. I found it is part number AJ87977. List about $190. Seems to be the same sensor for all models. Two bolts to remove and it's not too hard to get to. Car is running fine with just occasions of gasping for breath.

I don't see how a fuel pump would work better then worse??

I have replaced a good number of pumps on other cars. They either die (Not so common) or they slowly taper off on pressure and volume (most of the pumps I have seen).
.
.
.

 

Finally got my fuel pressure tester on the car and did some tests. First I had a very hard time finding the Schrader valve and the JTIS did not seem to show where it was? I looked for a while with no luck. Finally found it on the back of the fuel rail on the passenger side.

It looks like a fuel rail pressure sensor problem. I get almost 100 psi at times and then it's very jerky on the test gauge. The pressure tester chatters the pressure is fluctuating so much. Then it will smooth out and run in the 45-65 psi range which is normal. I even observed an almost 0 psi reading at one time and the engine tried to die. At 90 mph the car is doggy and it's reading 90-100 psi. One of my symptoms for the 0191 code is too high fuel pressure so it kind of matches what's going on.

I did get the electrical checks from the JTIS and will try to run those next to confirm what I am seeing.
.
.
.

 

Recording it via OBD at the same time and then graphing the values would be interesting so you could see if the two are similar or not. If not, faulty sensor. But otherwise... I'm not sure what it would be. (Even an elm327 can be used to record.)

 

Would check first what the true pressure is with a fuel pressure meter, then you will know if it is the sensor or something else (i.e. clogged fuel filter, fuel pump).
The P0191 is set when at idle the pressure is not as expected.

 

Thanks Avos but maybe I was not clear? I have a mechanical fuel pressure gauge attached to the Schrader valve on the fuel rail. So I am making a direct mechanical measurement of the pressure completely independent of the car and it's electronics as I drive around. I have the gauge on the windshield with the rubber hose going down to the Schrader valve.

Thanks Avos but the JTIS lists the following for code 0191:



No mention of idle at all?
Do you have any additional information for code 0191?
As I posted filter was changed several days ago.
.
.
.

 

I think either you compare with OBD or just change the sensor and hope.

 

Sorry, I don't keep track of double userids, only now I remember you are also tbird6 to which I reacted...

Anyway, the only extra info I read was that the measurement from the ECU is at idle (or coast down).

You may want to try a secondhand fuel pressure meter first; it looks either that or the pump. Not sure if a double reading next to each other (so pressure sensor/obdii pressure) would give a conclusion. With the IDS it would be easier, as then you can also check what the ECU is doing with the pump, that together with the other 2 might help to diagnose.

 

Sorry Avos about the double user names. I forget about it but it's confusing!

Looks like I found the problem. Followed the JTIS electrical checks and the sensor or transducer (It's listed by different names) has low resistance on one set of pins.

Just to let everyone know how to check the Fuel Rail Pressure Transducer. It's on the back drivers side on top of the engine. Bolts onto the fuel rail with a vacuum connection and a electrical connection attached. It's a 3 pin electrical sensor. The pin closest to the firewall is pin 1. They are all in straight line.

1. Between pin 1 and pin 2 it should read 10,000-12,000 ohms
2. Between pin 1 and pin 3 it should read 22,000-32,000 ohms
3. Between pin 2 and pin 3 it should read 22,000-32,000 ohms

Mine reads 1295 ohms on 1 and 2. Reads 45,000 ohms on 2 and 3.

It is item 4 below on the Supercharged/NA 4.2L engine. It looks like the 6 cylinder and 4.0 L engines use a similar but different part number. You can see the Schrader valve over by item 6 but it's not labeled.


I still was not sure it was the sensor but finally came up with an idea. I unhooked the sensor and let the plug hang. Then drove around again with the fuel pressure tester on the windshield. Much different! The pressure stayed around 45-65 psi with some variance as the RPM's changed. Never went to 90-100 psi and never dropped below about 45 psi.Car drove with pretty much full power again. Of course a constant check engine light but I expected that.

Called an ordered the part from what I thought was Nalley Jaguar. #AJ87977 List $190. I got it for $103 with shipping. Nalley has been sold (Don't remember what they are called now?) and the new owners do honor our parts deal of 15% discount and free shipping if the total is over $25. Call 1-800-328-4833 and talk to the parts manager Jeff Durham.

Maybe a moderator can update our vendor information? With the cost of Jaguar parts and the fact you can't get anything aftermarket it's a real savings to use them!
.
.
.

 

Henessey Jaguar/LandRover, Georgia took over Nalley inventory.

 

Wanted to report back on what is so far a successful repair. As I reported the car started running fine when I unplugged the fuel rail sensor. So I purchased the Jaguar part which is AJ87977. List is about $190 and I got it for $103 with shipping. One odd thing was the first sensor I got had the metal base plate installed either backwards or upside down. So everything worked but I could not bolt it down!! Got another sensor and it worked fine.

I do want to report that the Jaguar part is marked FORD and has a part number on it. I have now verified that this is another expensive Jaguar part that is used on many Fords including the Lincoln LS which makes sense.

So here are both part numbers and the current list prices:

Jaguar #AJ87977 List Price about $190
Ford #3R3E-9F972-AA which is printed on the part. List is about $45.

These don't fail too often but most Ford dealers will usually have them in stock. Unfortunately for me I found all this out too late and paid the big Jaguar price.
.
.
.

 

This seems like a common problem especially on the ford forums. I just called the jaguar and ford dealer for prices. List price jaguar $150, list price ford $144.

 

I ordered the part from car quest for $105 after my discount. They say it is a OE jaguar part.

 

You are not the first person to tell me Ford has really raised the price on this part. I think they must have caught on somehow to the big difference?

Glad you could get it after market but I paid $103 and used one of our forum sponsor’s. They are really a good bunch of people to work with.
.
.
.

 

carquest got it through world pac, it was a genuine OE part in the jaguar packaging so its not aftermarket, i guess the down side to ordering it from carquest is that it may be old stock of a superseded part. I have to order another one next week so I'll buy it from the dealer and compare.