I've had a strange thing happening for a couple of weeks now. When I park the car at, oh, let's say the auto parts store, then restart after 10 minutes or so, it runs very rough - barely wants to run at all. If I step on it a bit and run the revs up, it seems to clear itself and runs fine from then on. This won't happen if I'm away for only a minute or two, and doesn't happen when the car is cold. It finaly tripped the "check engine" light yesterday, and I pulled codes P0300, P0301, P303, P305 and P1316.

I understand that the P03xx codes are reporting the misfires, but don't really know what P1316, "Injector Circuit / IDM Codes Detected" means. I cleared the codes and it ran fine this morning, but I'm sure it would act the same if I tried to re-start after a 10 to 15 minute stoppage.

Any ideas and/or experience with this condition out there??

Thanks.

 

Larry,

I assume your are talking about the '05 XJ8, we don't often see this with the XK8.
The P1316 just goes along with a misfire code and is explained in the technical info as follows:

If, on the first trip, the misfire is severe enough to cause excess exhaust emission, the individual cylinder DTC plus DTC P1316 will be logged. The CHECK ENGINE MIL will not be activated.
If the fault recurs on the second trip, the individual cylinder DTC plus DTC P1316 will be flagged, and the CHECK ENGINE MIL will be activated.

One possibility to explain your symptoms is either sticking OR leaking fuel injectors on Bank 1 [pass. side]. They could be leaking fuel after shut off, which would flood bank 1, or stick closed and starve bank 1 on start up. I have seen both occur. Either way, once started and the RPM is increased, the excess fuel is burned off in one case, or the faster pulse width frees the pintle and lets the fuel flow again in the other case.

You could try having injector cleaner run thru the rail and injectors and see if you get any improvement. It works quite often for our customers, though not always.

Good luck,

 

XK8, XJ8L:
As I was preparing my 2 cents for your situation, I see a reply was sent.
I hope not to be redundant.
Should the misfire be sufficient to cause excess emission, one will get both the P300 series codes and the P1316. As for the Injector Circuit/ IDM (Ignition Diagnostic Monitor) code detected, the IDM is sending an electrical response to the engine control stating there is an out of spec condition, thereby giving you the reading -- in this case, the injector circuit.
I agree with the injector "open" theory or cylinder loading with fuel. After a short "shut down" period, not enough time has lapsed to "flood" the cylinder. Conversely, after an extended period, the fuel has dissipated. However, after the ten minutes you describe, fuel has flooded the cylinder(s) from a fuel rail leak down past an open (bad?) injector, bad (dirty) gas, or something holding the injector open, etc. Your attempt to start is met with excess fuel in the cylinder, possibly a spark plug wash down, a misfire and excess exhaust. Reving the engine will eventually clear the cylinder and "blow out" or burn the excess fuel.
Because the engine, other than during the 10-15 minute shutdown, performs as it should, it is doubtful that the electronics are out of spec.

 

This is interesting as I recently started having almost the EXACT same symptoms with my wife's 2000 Acura TL. The car starts and idles flawlessly when cold and also 90% of the time when warm. However, I noticed if we are doing a bunch of errands where the stop time is maybe 1/2 hour more or less, sometimes the car will start but quickly die unless I feather the throttle. The mechanic theorized it could be leaky head gasket that allows coolant to leak into cylinder when stopped and then burn off and he suggested a leak-down test. The test showed perfect pressure in all cylinders. I suggested it could maybe be a faulty throttle position sensor or idle air control valve that resulted in the computer sometimes being unable to set a proper idle.

However, I did not think of leaky/sticky injector which sounds more likely. The mechanic did mention that possibility and suggested adding a can of injector cleaner.

Let us know what you end up finding.


Doug

 

BG-44K in the fuel system. Cleared up this on my car!

 

Wow, guys. Thanks for all the great input. Actually. this is happening on the XK8. Many folks sing the praises of BG-44K, so I think that will be my first attempt at a solution. I did run a bottle of Techron through it about 4000 miles ago, but this has developed since then. I'll give the BG a shot and let you know what happens.

Thanks again,

 

We have found the BG-44K does work sometimes, but less than 50%. We have better luck with cleaner that is run through the fuel system with the fuel pump disabled. The engine actually runs on the stuff for a while. We use stuff called SynPower, made by Valvoline. By all means, try the BG first, but if it fails try the other route.

Cheers,

 

Any solution or update to this?

Doug

 

That's not a theory. It's a wild guess with no basis in how engines work. Sigh ....

 

Well folks, it's been about 3 weeks since I put the can of liquid gold (BG-44K) through the K-Cat, and I think the issue has gone away. I've been reluctant to declare victory because I've only encountered the triggering conditions a few times since then, but from a sample of 3 or 4 possible events, the score is still zero.

I hope it was that easy (which is seldom the case).

 

Hi Larry.......I have same issue as you. Has your problem returned after the BG-44K? If it did what has happened since......Thanks

 

Hi, Mick99. Actually, it has not been a problem until about 3-4 months ago. Happened again, but just for a short bit. I haven't tried another can of BG, but it only happened once.

Cheers.