My 2003 3.0 S-Type on cold start up I get the restricted performance message. Codes showing are P0171, P0174, P0300, P1316. As soon as the engine reaches operating temperature the restricted performance message goes away. I can clear the codes and no more issues until the next cold start. Any ideas ?

 

Yes - fix the cause(s) of those codes!

Stop damaging your car by just clearing the codes.

 

P0171 and P0174 would point to an air leak; but why would the air leak go away once the car reaches operating temperature?

 

You said you clear the codes. If you leave them do they self-clear?

Regardless, use fuel trims to diagnose (as about 1000 posts say).

You may well be causing cat damage currently and they cost lots. (Not to mention pollution.)

 

The below may help:

http://www.jaguarforums.com/forum/s-...ics-faq-52720/

 

Here's a good primer on using fuel trims to check for vacuum leaks:

JagRepair.com - Jaguar Repair Information Resource



2003+ V6 models are prone to damage on the bottom of the resonator on the intake duct. This allows unmetered air to enter downstream of the MAF sensor. This typically causes a lean condition on both banks, but it is very quick to inspect once you know where to look. See post #32 here:

https://www.jaguarforums.com/forum/s...2/#post1934812

 

It would also be helpful to know the number of kilometres/miles on the odometer.

Have the spark plugs and or coil units been replaced?

 

No they don't self-clear. At least not in the cycle between a cold engine and one at operating temperature.

 

152000 miles. Coils replaced with NGK brand and plugs. I have two of these cars identical spec. I'm going to swap MAF sensor, an easy thing to rule out.

 

It's one of the main possibilities, but don't focus on that alone. Check out Jaguar's official OBD codes here:

JagRepair.com - Jaguar Repair Information Resource


You've also got P0300, which is a random misfire. "Random" only means the computer can't pinpoint a specific cylinder. While I'm on a roll, I may as well get up on my Misfire Soapbox:

If the computer has set a misfire code, please be aware "misfire" wasn't the best terminology that could have been used. Misfire sounds like an ignition problem, at least to me, meaning the fuel and compression were there, but for whatever reason, the required spark was missing or weak. This might lead a good-looking aspiring mechanic to troubleshoot the daylights out of a perfectly good ignition system. I do not care to discuss how I know this.

In OBD-speak, misfire simply means one or more cylinders is putting out low power compared to the others. Pretty much anything affecting the output of a cylinder can set a misfire code. It can be low compression. It can be a valve not opening fully. It could be a clogged fuel injector. And yes, it could be an ignition problem, too, but don't overlook the other possibilities, too.

[/soapbox mode off]

At the link above, Jaguar has all sorts of possibilities for code P0300, copied below for your convenience:

ECM to ignition coil primary circuit fault (Cylinder misfire detected DTC also flagged)
Fuel injector circuit fault(s) (Injector DTCs also flagged)
Ignition coil failure
Spark plug failure / fouled / incorrect gap
Cylinder compression low
Fuel delivery pressure (low / high)
Fuel injector(s) restricted / leaking
Fuel injector(s) continuously open
Fuel contamination
Worn camshaft / broken valve spring(s

Note how they don't even mention a vacuum leak yet. Now take a look at the possibilities for P0171/0174. Note the very first thing on the list:

Engine misfire
Air intake leak between MAF Sensor and cylinder head
Fuel filter / system restriction
Fuel injector restriction
IP Sensor fault (low fuel pressure)
Low fuel pump output
HO2 Sensor(s) (1/1, 1/2) harness wiring condition fault
EFT Sensor fault (low fuel temperature)
MAF Sensor fault (low intake air flow)
Exhaust leak (before catalyst)
ECM receiving incorrect signal from one or more of the following components: ECT Sensor, MAF Sensor, IAT Sensor, IP Sensor, EFT Sensor, TP Sensor


#2 is a vacuum leak. But I'd certainly want to take care of that recurring misfire code. It's easy enough to rule out the second possibility of a vacuum leak, checking the short/long term fuel trims as described in an earlier message. If that's good, I'd concentrate on the first possibility.


Let's say the fault is right on the margin of setting the fault code and RP message. Just a wild guess, but maybe you've a defective coil with an internal short. Due to thermal expansion and contraction, the coil behaves once it reaches normal operation temperature. But when cold, the fault is active, hence the code and message. Or maybe the fault is an air leak, and with heat the gap closes up just below the threshold that sets a code. If at all possible, do your troubleshooting when the engine is cold and be prepared to work quickly before the engine warms up. This will obviously stretch out the whole troubleshooting procedure, but is your best bet of catching the fault if you can duplicate the same conditions, i.e. engine cold.

 

Karl thanks for a well thought out response. A lot to digest here and I won't be able to get back to the car until after the weekend. A lot of basic things on that list that I have not checked yet. I will report back when I have worked through the different things you and other forum members have suggested. Nick

 

Just a quick update. I bought a smoke machine; I've wanted one for a while. There is a massive leak around the intake manifold. It appears to be around the plastic interface. I'll post again when I know more and have a solution.

 

Good find! Thanks for the update.

Just curious, did you ever check the fuel trims as detailed in a previous message? If not, it's certainly worth checking before tearing things apart. I ask because it would be nice to know to what extent the fuel trims help. That is something we often suggest for suspected vacuum leaks. Most guys have at least a simple scanner (or access to one) versus few have a smoke machine.

I consider the fuel trim comparison as a very basic, preliminary step for troubleshooting and only takes a couple of minutes. A smoke test is more involved and much more specific, typically a later step to isolate the fault and only used after leakage is indicated by the fuel trims.

 

Karl, I didn't check the fuel trims. I only went through two cycles of the issues I described above. I could do that now; but it runs so badly on startup I'm concerned that I might causing damage. I'll post the brand and price of smoke machine later; I need to look it up. From what I remember it was about the price of a good quality code reader and very simple to use.

 

Could be a leak when cold then when warmed up metal expands and seals gaket or two. Possibly cam cover. I know a few members with that engine experienced bad corrosion of the cam covers and intake ports if i remember right

 

The smoke machine I bought is a Solary SD301. I paid less than I remembered $58 and change on amazon. Easy to use and money well spent in my opinion

 

Both lower intake manifold spacers had one insert each pulled out/loose. While it was apart I sent the fuel injectors to SD FAIRCLOTH in Florida for cleaning. I bought two used manifold spacers on ebay and new gaskets. Finished the reassembly today and s-Type is back to normal.