LBZ: Low boost no smoke no codes

[big block]

So just did head gaskets, egr delete and down pipe, truck ran great before minus the head gasket issue, now I can seem to make over 16 psi boost, no codes no smoke, truck is down on power, was running a Danville single tune before, spent the afternoon with a local tuner logging data and what not, changed back to stock and still no codes, tryed other tuning as well truck seems like a slug on the bottom end, pressure tested the intake and piping ect and its good no leaks, stumped any help would be appreciated.

Truck is an 07 crew cab service truck, big bastard 14 000lbs with f450 axles under it.

 

[smcdaniel]

Exhaust leak maybe? Check the up pipes on the back of the turbo.

 

[WVRigrat05]

So just did head gaskets, egr delete and down pipe, truck ran great before minus the head gasket issue, now I can seem to make over 16 psi boost, no codes no smoke, truck is down on power, was running a Danville single tune before, spent the afternoon with a local tuner logging data and what not, changed back to stock and still no codes, tryed other tuning as well truck seems like a slug on the bottom end, pressure tested the intake and piping ect and its good no leaks, stumped any help would be appreciated.

Truck is an 07 crew cab service truck, big bastard 14 000lbs with f450 axles under it.

See if your rail pressure is limited, it my LLY would limit fuel rail pressure to 10k but spike to 13k but only throw a soft code when I had a bad fuel temp sensor

 

[big block]

Exhaust leak maybe? Check the up pipes on the back of the turbo.

I don't hear anything leaking, everything was cleaned good, new gaskets ect, what should drive pressure be I wonder?

 

[big block]

See if your rail pressure is limited, it my LLY would limit fuel rail pressure to 10k but spike to 13k but only throw a soft code when I had a bad fuel temp sensor

Rail pressure is good, 26k under full throttle.

 

[IOWA LLY]

When the so called local tuner was logging it, did you monitor actual and desired vane position? Did he monitor mass air flow and verify it was within the correct parameters?


If you don't have boost or exhaust leaks, and your building good rail pressure, then either the ECM is limiting fuel, (most likely from low airflow) or the turbo is stuck wide open.

The only other possibility would be something stupid like a large rag left in the inter cooler or something.


Sent from my iPhone using Tapatalk Pro

 

[zakkb787]

That was my thought. Could be something finicky with the vgt system

 

[big block]

When the so called local tuner was logging it, did you monitor actual and desired vane position? Did he monitor mass air flow and verify it was within the correct parameters?


If you don't have boost or exhaust leaks, and your building good rail pressure, then either the ECM is limiting fuel, (most likely from low airflow) or the turbo is stuck wide open.

The only other possibility would be something stupid like a large rag left in the inter cooler or something.


Sent from my iPhone using Tapatalk Pro

Yes to my knowledge his was monitoring everything and it looked good, ran a stock tune also and no codes came up, at the end of the day he figured a boost leak still and I rechecked it but looked good, made 19 psi on hard hiway pull today, but low gears it gutless as can be.

 

[IOWA LLY]

Yes to my knowledge his was monitoring everything and it looked good, ran a stock tune also and no codes came up, at the end of the day he figured a boost leak still and I rechecked it but looked good, made 19 psi on hard hiway pull today, but low gears it gutless as can be.

So he verified that actual vane position was following desired?

And did he verify it was fully fueling? (Seeing at least 90mm3 at WOT?

You need to ask him these things specifically.


Sent from my iPhone using Tapatalk Pro

 

[big block]

So he verified that actual vane position was following desired?

And did he verify it was fully fueling? (Seeing at least 90mm3 at WOT?

You need to ask him these things specifically.


Sent from my iPhone using Tapatalk Pro

Sounds fimilare, I'd have to go back to get his logs or pay for more time to do it again, but I remember talking about all that, his only idea was moving the vane min and max around to make more boost but shouldn't have to because it tracks good, is there any scan apps that can read what efi reads? I'm not going keep paying a shop when I can buy a v2 and do the same, was thinking swap the ecm from my other truck and try it, out of ides...

 

[TROJAN366]

Sounds fimilare, I'd have to go back to get his logs or pay for more time to do it again, but I remember talking about all that, his only idea was moving the vane min and max around to make more boost but shouldn't have to because it tracks good, is there any scan apps that can read what efi reads? I'm not going keep paying a shop when I can buy a v2 and do the same, was thinking swap the ecm from my other truck and try it, out of ides...

If he didn't log these things to diagnose I wouldn't use him again.

 

[big block]

If he didn't log these things to diagnose I wouldn't use him again.

I'm pretty sure he did, if it was as simple as retune it and collect his money I'm sure it would be fixed, he spent a few hrs with me, if it's a lengthy process to find my issue I should just buy the gear, shop labour ads up fast, I don't think it's electrical now tho, need to look at a different way probably, like how can you manual alter it to dump fuel until it smokes and see how much boost will make, maybe its commanding properly but the fuel is just not there.

 

[big block]

Ok bit of an update, check turbo vane travel by removing the sensor, put 12 volts to the solenoid, get full travel and tried the sensor from my other truck,put the ecm in out of my other truck, cranked the ppe tube to 4, truck still under powered, makes 24 psi on that tune, should limp the transmission easily but no, I think it delivered 60 or so mm of fuel using the tuner to read sensors, gas and brake the truck will load up and kinda surge a bit like the fuel delivery can't maintain, work the throttle and you can find the spot where wants to go but cuts back, both throttle sensors read good, rail pressure holds steady 26k.

 

[big block]

Ok update I think I got to the bottom of this, sent injectors out for testing as per my hunch and he got through half of them and they all failed at 30% low on fuel delivery, I believe he said they were making only 60 mm3 of fuel when the spec is around 90, so tested spares I have and got 6 so buying two remans and hopefully she's running better then ever, I'll post an final update tomorrow hopefully.

 

[big block]

Injectors in and truck seems to be running good again Now that I have a guy local to tune it I'm tempted on turning it up more lol the Danville tune seemed to have a shorter defuel time then this tune witch I liked better I think, probably go talk to them and see what we can figure out, the local guy can do either Danville or his tunes.