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The first thing to check is the battery voltage.
An old and/or diying battery can cause all sorts of faults on these cars.
Make sure it is fully charged and has good voltage. (Post the voltage on here.)
Then try to reset the codes and see what comes back up.
Some background may well help as well.
Did this all happen at once? What are the symptoms?
Are there any warning lights etc?
Also please confirm the model year that is on the display, this is the 10th digit in the VIN number X=1999, Y=2000, 1=2001, 2=2002, and so on.
You can also always use the forum search function to find out info on the fault codes.
Mellow
Last edited by M-e-l-l-o-w; Feb 23, 2022 at 06:28 AM.
Some background may well help as well.
Did this all happen at once? What are the symptoms?
Are there any warning lights etc?
+1 on that. What symptoms are you seeing?
The codes starting with U may not be a big deal, and don't often present any visible symptoms. They all seem to be related to vehicle speed, such as the signal to the audio system to increase volume at higher road speeds.
The P1246 relates to a feedback signal from the generator. Is your battery light illuminated? Has the stock generator been replaced with aftermarket? Most aftermarket brands will charge just fine, but won't communicate properly with the Powertrain Control Module and the battery light will illuminate. In other words, P1246 is probably a normal code with an aftermarket alternator.
Thanks guys for the help here is a little more information
the car is a 1999 v6 3000cc
i bought it in October last year
the car ran fine when I first collected it and then I got problems
the car had been in a private collection and stored for some time (also it is LHD as I’m in Tenerife)
the battery is new and holds charge and voltage appears to be correct I’ll post a picture soon.
my first problem was that it stopped reving over 2500rpm and was back firing
I found two air leaks fixed these also have changed the coils / plugs oil air and fuel filters
As I have done this the car was running better but only lasts a few days
the cooling fan does not appear to be working but does not overheat also no hot air from the interior heater
the passenger door won’t lock from the key fob
there are no warning lights displaying
but my main problem is the engine not revving and appears to get worse as the car gets warmed up also when the air con is on.
hope this starts the ball rolling
kind regards
ps when I reset the codes the same faults show again after running the vehicle
the car loses power when under load sometimes cuts out I think it’s fuel or air related problems you can only press the accelerator so far then if you push it further it start to judder as if it’s not getting fuel hope this helps
Last edited by diamondtrev; Feb 24, 2022 at 06:04 AM.
Reason: More photos
the car had been in a private collection and stored for some time
Ah, big clue there. Many forum members have reported trouble with the fuel pump after extended periods of storage. In most cases, it doesn't run at all, but maybe it's only running at reduced capacity and the engine is starving for fuel.
Does your scanner show live data for fuel pressure? I'd look at that first, and make sure the value is within specifications. If the value shown is good, I'd then connect a mechanical pressure gauge to the injector rail. On the early V6, there's a fitting on top of the engine near the forward left corner, looking forward. IIRC, it's close to the oil filler cap and slightly inboard. Make sure the actual pressure agrees with what your scanner shows.
Originally Posted by diamondtrev
my first problem was that it stopped reving over 2500rpm and was back firing
When you say "it stopped revving", do you mean while stationary, with the transmission in P? Or do you mean while driving? There's a rev limiter when the transmission is not in gear, so that may be all you are experiencing if you're trying to rev up the engine while stationary.
Originally Posted by diamondtrev
I found two air leaks fixed these also have changed the coils / plugs oil air and fuel filters
Another big clue here. What brand of coils did you install? Some of the no-name Chinese specials, such as found on eBay, are pure junk straight out of the box. You'll want to make sure to stick with a known name brand, such as Denso, NGK, etc.
Originally Posted by diamondtrev
the cooling fan does not appear to be working but does not overheat
Be very careful here. This sounds like a separate problem, but be very cautious not to overheat the engine. Don't rely on the dash gauge. From about 180-230F, the needle is centered, regardless of actual temperature.
Details about the cooling fan here, including how to test and rebuild if necessary:
Possibly yet another separate issue. See this link for more details. Follow post #2 to test the Dual Climate Control Valve (DCCV), a known problem area. If the DCCV test okay, see post #6 for additional troubleshooting:
Can the car be driven at all? Some OBD fault codes don't appear right away, and may not be annunciated until certain parameters are met, such as driving at a certain speed, engine temperature, etc. So it's possible the computer will be able to give you some major clues, but you haven't reached the point where it will tell you.
Do the speedometer and odometer work? With several codes about a loss of vehicle speed data, I'm wondering how serious that might be. I'm not sure what sensors feed the speedometer and odometer, so knowing if they work properly might help sort things out.
Thank you for all the information I have started with the fuel pressure I am including two photos the first at idle speed the other with my foot down at about 2500rpm in park the problem is the same in park and driving
I have found that the cooling fan does work when I put the air conditioning on
also the speedometer and odometer are working correctly
Stagnant fuel can gum up the fuel injectors too. I had a similar problem with an '01 that had been sitting for a few years when I got it. Soaking them with throttle body cleaner and injecting it through whilst using a small battery to open and close the injectors worked a treat.
Fuel rail pressure should be approx 300kPa at idle.
Did you replace the lower crankcase elbow breather hose? A common failure on early cars and worth doing if you have the intake manifold off.
Are your fuel trims telling you anything?
Good luck!
Your scanner is only showing about 60% of that at higher RPM, so something ain't right there. The engine is starving for fuel, especially under load. Take care of that first, and then proceed from there. Lots of possibilities, such as a clogged fuel filter, tired pump, low voltage to pump, etc.
In the rear power distribution box in the trunk, inspect relay #6 for the fuel pump. Look at the prongs for any discoloration due to overheating. For giggles, I'd try swapping this relay with another known-good relay of the same size. If your fog lights work properly, relay #7 in the front power distribution box (under the hood) would be a good donor. You can see the relay in figure 03.6 here:
For the DTCs starting with the 'U' prefix, check the looms and connectors for corrosion/damage as there is a communication issue along the CAN-BUS.
What is the battery voltage with the ignition in the OFF position when checked with a voltmeter across the battery terminals? The age of the battery is irrelevant.
The PCM controls the cooling module on the radiator based on input from the cylinder head temperature sensor on the Bank 1 head.
The PCM will not allow the engine to exceed 3000 rpm without a load to protect the connecting rods. Revving the engine with the gearbox in 'P' or 'N' positions is not a good idea.
=kr98664;2500699]Making some progress! You have already found one major problem. There may be others issues as well, but for now I'd concentrate on the fuel pressure.
I don't have access to my manuals at the moment, but according to this you should be seeing 330 kPa (47.9 PSI):
hi Guys I’m back after a short break in the UK I’m trying to replace the fuel pump in my car as before I went away the pressure dropped to 156Kpa I can’t seam to be able to remove the sender unit from the tank it appears solid and I don’t want to cause any more damage can any one tell me if I just have to force it or is there a better way and does anyone know the part number for the filter attached to the side of it
Your scanner is only showing about 60% of that at higher RPM, so something ain't right there. The engine is starving for fuel, especially under load. Take care of that first, and then proceed from there. Lots of possibilities, such as a clogged fuel filter, tired pump, low voltage to pump, etc.
In the rear power distribution box in the trunk, inspect relay #6 for the fuel pump. Look at the prongs for any discoloration due to overheating. For giggles, I'd try swapping this relay with another known-good relay of the same size. If your fog lights work properly, relay #7 in the front power distribution box (under the hood) would be a good donor. You can see the relay in figure 03.6 here:
There are a couple of clips that lock the fuel pump in the tank. Looking at your last picture you can see one clip at rougly the 12 O'clock position at the top of the assembly. There is another clip opposite. I think from memory you squeeze them in and the fuel pump will unlock and you can wiggle it out. Be careful of the float that sticks out further than the access hole..
Perhaps Somone who has pulled a fuel pump out more recently may confirm whether this is correct.
Hi Guys I’m still having problem I have now replaced the fuel pump pressure show 330Kpa and run quite sweet until I had done a few miles and the car got warmed up then it started again and when checked the digital fuel pressure had dropped when the car goes cool it runs ok could this be a faulty sensor at the end of the injector rail ?
any more help is greatly appreciated.
ps I’ve also change the fuel pump relay and this made no difference
