high neg ltft/possible hpfp or hpfs

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Fuel rail pressure 1600 psi at idle. new offsore high pressure rail sensor about 5 weeks ago.Started running the corn juice around this time had added flex sensor ,an the e92 was already set up with proper tables for it.Dont smell fuel in oil.Not Sure if iam have a faulty sensor or pump.Heres log gets warm if iam not gassing her up,running seperate wideband and its not far from stioch.Iam wanting to believe sensor an not the pump.I also blocked off vacum at intake to lower valley cover just see if it was puicking up crankcase fumes.Nope they still climbed to neg. 35 both banks.

[cadillactech]

Why don't you log commanded rail pressure and compare it to the actual rail pressure?

Just a quick look at the commanded rail pressure table shows its pretty close.

Is this a swapped 5.3?

What modifications have been done?

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stock tune in c1500.have changed rail pressure sensor an hpfp.still getting high neg fuel trims.ive looked at scanner an added pid for fuel rail desired there close to each other under load.checked vacumm.an have wide band aem its running stioch.as far as wideband saying.but pulling max fuel even though there neg 30. an its still rich misfires here an there.mabey loose terminal pins injector, hell lost.

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fuel rail pressure high at idle almost peeged at times.
not sure if aem interfering with pid in scanner an it tring read from that.or running ethonol.an sensor took crap did the reset on it under scanner. this swap was a flex motor all tables where there in editor. just added cheap continentail. filled up 3x each time 30 50 70 percent. was running so rich had change oil. an thought hpfp failed.have back up rail pressure sensor there same.just at a learning curve here.probably maf sensor it worked great till 3rd fill up came outta 3,6 caddy. has same oem number for maf used by gm for there 8 wire. using 3.5 pipe so its as factory as can be but returnless fuel an guage dont fall couple psi under load.always ran it right at 70 psi walboro ti pump.

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id figure leaky injector would drop rail pressure low an flood it.

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well looking at the maf its alful high an that more air means more fuel correct?

[FastV]

stock tune in c1500.have changed rail pressure sensor an hpfp.still getting high neg fuel trims.ive looked at scanner an added pid for fuel rail desired there close to each other under load.checked vacumm.an have wide band aem its running stioch.as far as wideband saying.but pulling max fuel even though there neg 30. an its still rich misfires here an there.mabey loose terminal pins injector, hell lost.

2 things come to mind.. You said you blocked off the vacuum side of the pcv to intake, but did you block off the valve cover hoses to the induction tube? Also you mentioned you changed out the HPFP, but did you change the engine oil? That truck is getting really hot up to 225 degrees I saw. Fuel in the oil will boil and vapors can enter through the induction hose if it isn't blocked off causing the o2's to read the additional vapor and adjust. Just a thought...

Good luck,
Ryan

[FastV]

well looking at the maf its alful high an that more air means more fuel correct?

Its high, and yes that means more air so it will add more fuel. Simple way to tell is unplug the maf and allow it to run in SD mode. Wait till the check engine light sets the MAF code and then it will run on the back up fuel. If trims come back in line then the MAF is the issue.

Kind Regards,
Ryan

[FastV]

id figure leaky injector would drop rail pressure low an flood it.

Although injectors leaking on these are an issue you would have to have more the just one leaking as your fuel trims are negative on both banks.

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did unplug maf an they went positve real high almost 20.maf sensor came from caddy 3.6 an worked great for week or so does run a little better in sd mode just need tune maf again or new maf.praying its not loose terminal in harness have abused it good unpluging alot.

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have changed oil also.

[FastV]

did unplug maf an they went positve real high almost 20.maf sensor came from caddy 3.6 an worked great for week or so does run a little better in sd mode just need tune maf again or new maf.praying its not loose terminal in harness have abused it good unpluging alot.

Was that the short term that went positive real fast? The last logs you sent I still see its high negative fuel trims. Do you have a log with the Maf unlplugged? 3.6l Maf is definitely not the right maf for this. The hertz vs fuel will be way off. A V6 will have way less airflow than a V8.

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hers maf unplugged went negutive 30 to plus 30.will me ve table self learn this far of or do i need tune maf an sd again? iam i missing somthing?

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just went did a log
mabey leaky intake gasket

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when i used that maf had same part number as some gen v lt use. ran great for days.had upgraded with flex sensor an this was flex truck motor all dtc an everything enabled. after third time fueling an percentages from first to last fill 30 50 70 well here we are reset flex sensor fuel pump replaced high side low side mabey psi or so under load. getting comanded as close as disired on hpfr.need i log more.i was under empression maf sensors all same its tune that determines its reading as in generation platforms its oem one an has same part numbers some l83 use

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wideband also says 20 percent lean now also.

[FastV]

just went did a log
mabey leaky intake gasket

leaking intake gaskest would a lean condition. You have a rich condition.

[FastV]

wideband also says 20 percent lean now also.

Are you reading it in Lamda or In AFR? Remember if you are reading in AFR its way richer than gas so that will throw you off. On Lamda you want to target 1.0 for Stoich and Around .85-.89 for power enrichment.

[FastV]

The long terms are going more positive over the course of running it and the short terms went way positive right off the bat. In fact, the short term went as much positive as the long term was negative. This means the MAF was reading inaccurate. Remember to reset the long-term fuel trims when your in SD mode and drive again. This is fresh starting point and will it reset the short terms as well. let it idle for say 5 mins warm then drive. Make sure to log the whole time. Let's take a look at it them. My guess is your fuel trims on the long and the short will be within +- 10% which is normal especially if the VVE table has been touched.

[FastV]

Send over your stock tune so I can compare the Maf scaling. Looks like you have way more fuel being added than I do on my 6.2l Truck