Hello, new to the forum, friends and family told me about this so just to say hello, and hope you can help.

X300 over fueling....

upon start up cars fine.....not to long after as happens in different times, car stalls! Fails to restart smells likke running on neat fuel.

Cats have been replaced...lamba sensors as well

the impresson i get is air mixture failure, but could be wrong....i bought it like this with little knowlegde of the problem.

anyone had same problems or similar............? if so would be gratefull on a little bit of guidence.

Tanks alot Mick

 

Welcome to the forum, Mick. Make sure to go to the New member section and post another "Hello." While in there, may as well post a few replies to others to boost your post count above 10, then a mod may happen along and upgrade you to "personhood" - sorry can't remember the term..."full access?" Anyway...you'll need that to see pdf's and such.

Meanwhile...is your stalling tied to engine temperature at all? Sounds like it is not a set amount of time after start-up, but still could be at a near const. eng temp depending on ambient and your operation characteristics. Mine runs like a sewing machine crafted by a Swiss watchmaker, so haven't really studied the misfire/stall threads, but remember a few members having some issues that they thought may have been an electrical short in the inst. panel cutting out the ignition but it was just a bad coil or two. I'm guessing coils - pop the cover off and fire it up at night and see if you get a lightning show on top of the mill just before it stalls. Others will happen along presently with a far greater bank of knowledge than I, and you'll get it sorted in short order, meanwhile, welcome again, glad to have you here.

BTW, no idea what "neat fuel" is.....I thought $1.00/gal was horrendous when it first breached that threshold...but now I think $1/gal fuel would be pretty "neat!" Guess you mean something else, though

 

Thanks for the reply "neat" meaning un mixed fuel fuel and air mixture are needed for stable running, can u explain a little further, pop off instrument panel cover ? In side the car yes? And lighting on the top of the mill? My apologies its probably a simple check just want to make sure
Thanks mick

 

I think aholbro1 is referiing to arching of the on-plug ignition coils. If you remove the plastic cover on the top of the cam cover, then you will be able to see the ignition coils. With the engine runnin gin the dark, you may be able to see signs of arching from any craks inthe coil to the magnesium cam cover.

If the engine initially runs fines then starts to run very rich and stalls I would strongly suspect that the wiring to the lambda sensors has been connected back to front. You said that these sensors had been replaced, so the wiring may have been mixed up at this point. The engine ECU does not use the singals from the lambda sensors when the engine starts from cold. The ECU only uses the lambda sensors above a certain coolant temp, which couldexplain the delay before the problem arises. If the wiring is back to front 3 cylinders will run 255 too rich and 3 will run 25% too lean. This would explain the smell and the tendancy for the engine to stall.

 

Wow...I really boned that explanation up! Thanks to XJReng for fixing it up. What he said! Yes, inst. panel inside in front of steering wheel...but that was just a symptom some members were experiencing in another temp-related misfire/stalling post, and the culprit turned out to be cracked on-plug coils. But I don't think any of them were getting a fuel odor.

....so I'd check lambda wiring per XJR's post first. The failure mode seems a near perfect match for what you are experiencing.

 

Wiring on lambas is correct as per wiring diagram yellow wire is showing 5v constant signal I now have another issue folks

Battery went flat/dead now car won't start!! Ignition lights go out on turning of the key can't believe how much trouble one car can be

 

The ECU software includes lambda sensor orientation software. This means that it is possible to reconfigure the ECU so that it works correcly when the lambdae sensors are connected the opposite way round to the nominal arrangements. If this software function has been performed at some point in the past, the closed loop fuelling will than not work correctly if the lambdae sensors are connected up the nominal way round. Sorry if this sounds confusing, but it does mean that the sensors may not operate correctly, even if they appear to be wired up correctly. Connecting a diagnostic tool that can read the closed loop fuelling corrections will determine if this is the case, once and for all. You can check this out, when you have got the battery recharged.

 

Won't restart no lights indicators or ignition crank control box or ignitik. Module at fault now

 

Hey Mick, they are also known to be finicky for good, solid, clean tight "earths" and I think there are only about a coupla hundred spread all over the car.....

 

Mick,

I have read all this many times, a tad slow on the uptake sometimes.

I posted here a short time ago about the FPR (fuel pressure regulator) on these is the SAME as one of the FPR's on the mighty V12's, and we have had all sorts of dramas with those FPR's over the years.

They are habitual for rupturing the diaphragm, and since they are vac controlled, that small hose sucks RAW (neat) fuel into the inlet manifold and the engine overfuels (floods) and the thing stinks of fuel.

I would remove that small hose and sniff it for fuel odours, it may NOT be your issue, but costs nothing to look see. These FPR's are all about 16 years old now, and that is about the age they starting giving grief on the V12's.

The no instrument lights issue is more than likely battery cable, +ve and -ve , that are now testing your patience.

 

Okay this is a straight 6 xj300 model where knthe engine I the regulator and what, pipes do I remove thanks

 

I know it is a 6 cyl. As I said I read your post CAREFULLY.

Locate the fuel rail, under the narrow plastic cover on the LH side of the cam cover. The fuel rail is a metal "tube" with 6 connectors for the 6 injectors, and an inlet connection (double nut thingy) at the rear, and at the front is the FPR, and that FPR has a small vac hose attached.

Pull that hose, and have a sniff, you will smell petrol if the unit is ruptured. If in doubt turn ON the ignition (fuel pump will run for 2secs), DO NOT START THE ENGINE, and see if fuel flows out of the same spigot you took that vac hose off of. If you do, it is toast, if not, it is deemed OK.

As I said these are the same part ## FPR's as our V12's, and that unit on the V12 is soooooo common for overfuel issues it is scary.

If all is dry and sweet, then my suggestion is WRONG, and you have other demons to deal with.