HI, long time no write, hopefully someone can be of some assistance here! Last Wednesday on my way home from work i noticed something wasn't quite right with my STR. It felt sluggish, even maybe starving for fuel or air. i took it easy going home and poked around. The air box was clear it idles fine runs up in rmps fine and no codes or check engine light, so i take it back out and throw some throttle to it just to see what happens...well it comes up through 3k rpm fine then around 4 it looses power and it sounds like someone is under my hood shaking a can of marbles.(uh oh) it kicks into restricted performance and i believe i have blown this motor. Unexpectedly the RP leaves and even the check engine light goes away and everything seems fine. i limp it home thinking this is the last time this thing runs with this motor in it but when i get home once again i cant find anything immediately wrong. I just got it into a local shop here since the jaguar dealer has closed and they diagnosed my STR with a bad supercharger. I personally have no experience with super chargers but it seems like something else might be wrong. maybe the second fuel pump isn't kicking in or maybe a bypass or something is stuck closed? it seems odd the super charger with only 60K miles would just go from fine to destroyed with no squealing shaking or other symptoms...id love some other input. Thanks guys!

also forgot to include: only stores codes were miss fire on all cylinders and a p1410 which is on the ticket but was not explained to me

 

Welcome back styper526. Though jagv8 and others will be here soon and are much better at helping you diagnose your issue, I can tell you it's highly unlikely the s/c is at fault. My 106k 03 STR still has never had a problem with the s/c (knock on wood). It's common for the COP (coil over plug) ignition coils to fail and set off the protective mode of the car. Though not likely in your case, oil leaking from the valve cover can foul a COP. Begin with checking the state of your battery's charge, as weak cell(s) will start her but not maintain proper voltage to fire the ignition system adequately. A weak battery will be stressed further in a cold climate. If your on the original battery, ditch it, then move on to testing or replacing coil(s), etc. I'll be "lurching" in the background of this thread.

 

Relax. Motor's not blown, most likely the SC isn't toast either.

P1410 is a secondary air injection system valve stuck open.
Basically the car has a stupid (imho) secondary air pump. Its purpose is to lean out the mixture when the car is cold by injecting extra air into it. This in turn heats up the catalysts faster, and basically gets the emission control system doing it's job quicker.

Sounds like that valve went open for whatever reason, and leaned out the car, causing all the misfires.

Take care,

George

 

That must be another P1410.

The DTC PDF in JTIS is also in the FAQs here and shows:
P1410 Air cleaner solenoid valve drive circuit malfunction

Which I think means that flap in the bottom of the air filter box.

I don't see why that and lots of misfire codes would all occur at once unless there's an electrical problem (probably, not definitely).

That could be chafed wires, bad battery/alternator, or something that I'm missing right now.

I agree it doesn't seem likely to be the SC or indeed the engine.

However, it's not gonna improve their health if it keeps doing it!

 

styper256, did you recently fill her up? I'm not trying to entirely stray away from an primary electrical issue but don't want to rule out fuel starvation either. You're initial intuition was a failed fuel pump...You may be further here than just a guess.

 

Wait..... I think we are talking about the same code, but the S-Type may use the flap to control the secondary air injection.

If that is the case, Does it not open up to enable more airflow when cold? Or not close to restrict it? Seems to me the flap MAY be stuck open.

Sounds like the car is leaning out... Oil and stuff like that hitting a coil pack will not cause a misfire or ALL cylinders (just the oil affected coils).

Seems to me like the mixture is off. Do you have any scan tool where you can monitor the pre and post cat 02 sensors? They will tell you a lot about the mixture.

Take care,

George

 

Er, secondary air is air put into the exhaust, isn't it? Not done on his era STR, I believe.

The flap mainly (only?) opens at very high air demand e.g. WOT. But lack of the hoped-for air shouldn't cause misfires should it? The PCM will see the actual air via the MAF and just add the right fuel (plus extra if WOT so it runs rich), won't it?

If this is at high air demand (such as WOT) I don't think the PCM uses the O2s much if at all at that time. Not sure about this part but it's true for some/many engines.

 

If the engine leans out it will. At some point you're going to run out of air regardless of fuel to spin an engine at a certain RPM. Notice according to the OP, the engine didn't misfire till past 4k rpm?

It's either starving for fuel or air... The PCM can only compensate SO much, eventually it will lean out and detonate (misfire). the PCM senses this, and shuts the party off with the restricted performance.

I was speaking about monitoring the voltage of the 02's to determine if it's leaning out when it misfires.

This is starting to sound more like a fuel delivery issue though the more I write and think about it. Although that code points to an air issue of some sort.

To the OP: Does the car run perfectly FINE below 3k rpm? Idles smooth etc.

Take care,

George

 

What I'm saying is that the PCM will if anything try to go a bit too rich so yes something is quite wrong. It could be not enough fuel is being added or the mixture is not burning properly - which leaves unburnt fuel and unburnt air. Only the air is detected (O2 sensor) so the PCM will then add yet more fuel.

If the car starves for air it will add the right fuel for the air it has. Not go lean. Not misfire. You'll just not have the power you expect.

Reasons for not adding enough fuel: injector trouble, fuel pressure / flow trouble, MAF misreading, air leaks. (Did I miss any? LOL)

So, read fuel trims. At idle and at (say) 2500rpm (or faster). Those readings will determine whether it's an air leak.

Watch the O2s if you know what they should look like. Upstreams and downstreams use different technology and behave completely differently on these cars. Let's not look at O2s yet! No O2 codes so they're probably OK.

 

I did read somewhere that if you remove the flap you have to keep the solenoid mounted and still plugged in cause it will throw it into restricted mode if its not. Also just curious is the Air cleaner solenoid valve just another name for an EGR valve. And the STR doesnt have an EGR system?? Just curious never really researched much into our engines.

 

The STR has EGR as well. EGR = exhaust gas recirculation. Literally, some exhaust gas is allowed back via piping (and a valve to control the amount) into the engine. Because it should be burnt fuel/air (if no misfires), it should have almost no O2 (and no fuel). It's mostly nitrogen (as air is), which is almost inert in this use, with the rest hopefully being CO2 and water vapour (results of burning the fuel). The result is a cooler and slower burn, thus reducing emissions and apparently slightly increasing power. (If I'm remembering right. google's a place to check.)

 

I don't think this is an o2 failure. You would run rich as hell, and have catalyst inefficiency codes.

This flap we are talking about is before the MAF in the intake path right, so in theory, the flap's position (regardless if erroneous), would not result in unmetered air right?

I'm wondering what the fuel pressure overall is like. A simple OBDII scanner will tell us that much. This sounds more and more like a fuel delivery problem. Something is messing up the mixture here. That's the only time I've ever seen ALL cylinders misfire on a car.

This code is interesting, but may not be the root cause.

If this code on it's own throws restricted performance that's one thing. But a series of misfires, especially across all cylinders, will also throw restricted performance, almost instantaneously.

Take care,

George

 

A while back when my 04 STR was under warrantee, I was complaint about some noise. Went out with a jag tech and did some WOT pulls with and without the wires to the airflap motor connected.

In both cases, with the flap closed (disconnected) at WOT, the engine ran fine to redline (as close as it goes in 1st and 2nd gear)

Also with flap disconnect, he had to clear the code with a hand held scanner but did not cause a restricted performance.

Experiment was repeated twice with about 5 to 10 pulls each with flap connected and disconnected.

 

..HI Vance, just out of curiousity, didn't you make a youtube video on removing the Flap from the air box? After removing it, did it throw a DTC Code out? This is the same Flap what everyone is talking about right, or did I miss something,,Thanks

 

I did make a video but it was the flap in the airbox. In the video I only remove the flap the solenoid and the wiring all stayed and was never removed. So it still tries to open it but its already open so it functions as normal you just get the extra air all the time. I did this cause I thought I had read that it causes problems if its disconnected plus it really doesnt no harm to just leave it.
I believe they are talking about a different flap farther along in the intake.

 

The airbox flap is not the cause. This is either ignition/electrical, weak battery, fuel/fuel contamination, or vaccume leak aft. MAS. Doesn't sound like much could go wrong, huh?

 

....LOlz , my bad, but its good to know that removing it won't cause any harm Thanks..

 

That IS the flap I'm talking about and as I've said I do not believe it can cause lean codes. There is NO air flap further along the intake (apart from the throttle plate LOL).

 

Please be exact: which misfire codes did you have? Really all of P0301 through P0307? Any other misfire ones?

If you can't be sure, to avoid a potentially LARGE bill buy an OBD tool and read them yourself. Make sure it can do live data such as fuel trims. An elm327 from ebay will be around $20-30 and you need a PC/laptop or a handheld will be $60ish.

 

thanks guys for all the replies and help! to androulakis yes the car runs great under 4k, starts right up, idles smooth, plenty of power. its just in the upper 3's and right at 4k where things get weird. and to jagV8 the tech did not list all the misfire codes on the ticket he simply told me i have misfires on all cylinders. I had my wife sit in the driver seat and i looked down in the air box while she stomped on it once and the flap in the bottom of the air box is opening and closing so that does not seem to be an issue.