Measureblock 140 shows rail pressure if that is what u are looking for, remember to see both engine module 1 and 2, for both rails.
You have to get it up to operating temp first correct?
Everything is better at operating temp, but technically, might not be nessesary here. The HPFP are camdriven, so affected by RPM alone. Regulator not sure, but most likely minor, if any, changes from engine temp.
I’ll try that tonight, I’m thinking it’s my hpfp’s but I’m hoping it’s something else. Those damn things are not cheap to replace
So I checked the fuel pressure and this is what I got:
Sorry for the crappy pictures but my garage laptop doesn’t have many programs on it so I had to take a picture. The most it got up to with a blip on the gas is around 10 bar on both banks. Also I tried to do the intake flaps reset but I jet get an error:
Anyone have any ideas what could be causing that?
Does it even run at this point? The two rails are connected if im not mistaken, so somewhat even pressure is no suprise. However, even 1 HPFP alone should manage higher pressure than that without an issue. So I would honestly guess its one of the following;
HPFP not getting sufficient fuel(clogged filter, or bad LPFP)
Fuel pressure regulator faulty, just trying to constantly dump pressure.
Fuel leaking out, not able to generate pressure. But this would smell instantly and be obvious.
Both HPFP unable to generate pressure could indicate both pumps being bad/bad cam follower.(Unlikely because of the symmetry).
Faulty pressure sensors(Unlikely because of symmentry).
Does the car run? Idle? Alright? Terribly?
There is only one fuel pressure sensor (G247) on the HP side. It is located under the IM. Both Engine and Engine II modules report values from this sensor.
Fuel filter? Incorrect flow or low max pressure (once i had filter with lower max pressure than oem, and i get error low pressure)
HPFP have small filter similar like on pic belove, maybe they are clogged, in one of my hpfp filter had some derbs
Get pumps out, check cam followers, clean up pumps and try again. Or maybe yours hpfp pressure regulators stuck so it bypas pressure, can check that with 12v if they clicking and “pin” is moving
It is idling ok-ish but not great, once it calms down it will just sit and idle. However it’s very rough at startup
In most configurations cold start on the 5.2 V10 is a bit rough. On the cold start the 02s are not giving feedback until they’re warm the car is basically in open loop. So the car will idle with what is basically your last LTFT data.
The JHM tune helps this quite a bit by sorting out some of those issues.
Still your fuel pressure issue seems like it too could be playing a roll. Not only that but I’d be worried about the possible fuel starvation on WOT
Mine has lumpy idle on cold start or 3 or 5 seconds and then it goes 100% smooth. I always assumed it was waiting for O2 sensor data like you just described, good to know…
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If I give it any gas it doesn’t like that at all, so I’m thinking something is wrong with the high pressure pumps. I’ll have to try to pull them off to see if there is anything visually wrong with them
I’d say there are no fuel leaks either from what I can tell. There’s no fuel smell and I don’t see fuel anywhere
Try unplugging their pressure regulators one by one and see if that changes anything. From my expirience anything above 6 bar on idle should not have visible impact on engine smoothnes.
Thanks I’ll give that a shot this weekend when I’m back in town
Does anyone have an idea what’s going on with the intake flaps? It’s just showing an error. When I had the intake off the were in good shape and moving freely, could it just be a bad actuator?
Poking around tonight I think I figured out one of the fuel pressure issues, don’t suppose you can just replace that clip where it threads into the hpfp can you?
Plenty of those regulators on ebay and aliexpress
I have two of them and no any issues with them
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The 4.2 ones are the same?
Same on 2.0 and another engines if same valve model type they all same. I have two of them, no any part numbers or letters on them, jhm tuned and no any issues