Hazmatt81

People of LS1Tech I need some help I'm sure if we put our heads together we can resolve this issue.
I will try to be as descriptive as possible without putting a bunch of unneeded garb in here.
I would also like to try to keep this as professional as possible without getting into company name bashing and who makes a better part than another.
Background: 1997 GMC sonoma swapped with a 5.3/4l60e and a 70mm turbo charger, tial wastegate, aeromotive FPR, and 73 Lb/hr injectors and walbro 255 fuel pump with racetronix hotwire kit. Truck ran great last year went on power tour etc. Over the course of the winter I swapped out the truck intake manifold to a LS6 intake manifold with new sealing rings for a cleaner look and changed the intake piping to remove the MAF and insert a IAT for a speed density tune so i can run more boost since the MAF had reached its max potential. I also had to add injector 1/2" top hats to the injectors to make the Short injectors work with the LS6 intake.
FFWD to today: I have the tuner come out to adjust for the changes and the truck wont start and idle on its own without adding 192% more fuel to the fuel table. At this point its not drivable if you try to drive it it chugs along just like if you were to take the air intake hose off behind the MAF and try to drive around, or like if you have a massive vacuum leak on your intake manifold. All parts on the truck are approx. 2 years old now.
The tests I performed so far to diagnose the problem are;
- with the engine running I have sprayed ether/carb clean/propane around the manifold to look for leaks and see if the engine revs or not. no change
- I have removed the intake manifold to check for cracks, found nothing.
-new O-rings on the fuel injectors. no change
-changed the fuel filter. no change
-pulled the Fuel pump out of the tank to look for a split hose or something found nothing
-pressure tested the fuel system at the rails (dead head method) peaked at 70psi. after 5 minutes it fell to 45-50 psi and held it there. When the engine was running with the extra commanded of fuel delivery it was running at 58 psi.
-swapped out the IAC no change.
-I have looked over the intake for a missing vacuum hose. even the HVAC one is hooked up (commonly missed). so no ports are un plugged.
-Intake is properly torqued to 90 +/- inch/lbs using a 2 step process and proper sequence.
-Pulled hose off of FPR to look for fuel in the vacuum hose. -none

-tests i can't perform. I can't KOEO and hold pressure with this Aeromotive FPR. it springs up to 58 and falls immediately. Aeromotive says that their FPR's are not meant to hold pressure they are meant to perform. Its in their websites FAQ's

-Tests i haven't completed yet.
-Fuel volume test.
-cleaning the injectors.
-smoked the intake for leaks.

Could when I modified the fuel hose (Braided stainless) to make it a wee bit shorter after the rail going to the FPR could something clogged somewhere or something making this thing not run?

As stated above with the fuel table where it should be the truck will start use its start up fuel and then die Almost like the VATS isn't deleted. it you spray Carb clean in its throttle body it will stay running but as soon as you quit the truck quits too.

Anyone have any Ideas? Like i had stated before all parts are new within 2 yrs and known to be good. I think its really weird that I changed basically 2 things and all the sudden i have a truck that doesn't work at all.

Any help is appreciated.

JoeNova

How was it switched to SD? Did the tuner actually update the operating system and then disable the MIL stuff for the MAF?

If he didn't switch to 3 bar SD OS, then it's not going to like running without a MAF.

Also, check IAT signal with the key on and make sure Temps are where they need to be.

Hazmatt81

I can ask him how exactly he switched the tune to sd. I don't want to offend the guy, by questioning his integrity, 'cuz I know he has done several of these set ups before. But that's not to say he may have accidentally missed something. Thanks Joe

Old Geezer

iTrader: (3)

"tests i can't perform. I can't KOEO and hold pressure with this Aeromotive FPR. it springs up to 58 and falls immediately. Aeromotive says that their FPR's are not meant to hold pressure they are meant to perform. Its in their websites FAQ's"

Falls to what, zero, or? It's not going to maintain the 58, once the prime cycle is done. If that Walbro has a faulty check valve, the psi will drop... Sometimes directly to zero.
What do you see on the gauge while it's running on start fluid? Zero? if so, the pump is not being restarted after the prime is done. The ecm must see a rpm signal for it to restart.
A noid lite on the injs will tell you if they are pulsing when cranking.

If this tuner is butthurt by you asking some ??'s, find a new tuner. Just sayin...

RixTrix

A tuner is not just a guy with a laptop and some software.

He (should) have an intimate knowledge of the system and be able to quickly isolate major issues by observing behavior and data stream (Logging?).

Some of the obvious questions are,
fuel pressure while running on spray cleaner?
Which PCM?
Which OS?
Was the wire harness changed?
Does it need to be re-pinned for SD?
Have you added the correct MAP and have correct vacuum source?
What does the data stream show?
Trouble codes?

Note:
The dead head fuel pressure test sounds low? Seems to me it should go over 70#. However Im not sure its a valid test and may damage pump? Does a 255 have an internal pressure relief valve?

http://walbrofuelpumps.com/fuel-pumps-pressure-charts
Shows a max (working?) pressure of 87#
and a no flow pressure of 130#

Hazmatt81

I'm going to try to answer as many questions as I can.
OS=HPTUNERS
ECM=2001 Silverado I believe that's a 411.
Has the wire harness been changed. Yes I am running a current performance wire harness. It used to be a 5 wire MAF. I unpinned and used the IAT wires and pinned them into the IAT sensor.
Correct MAP sensor. I purchased the 2.5bar MAP from Dave Steck. And gave the values that came with it to the tuner.
Correct vacuum source. The map is plugged in and inserted into the manifold.
I don't know what the data stream showed except for it wanting more and more fuel. Even at 192% more at idle the fuel trims were adding more.
I don't know of any trouble codes

As far as the fuel pump goes and the questions your asking I'm not sure if I can answer those.
What I can say is I tried a very backyard fuel volume test by looking up the chart of the pump on line hooking a graduated jug to the return line AFTER the regulator which is the last component of the fuel system. Hot wired the pump to the battery, ran it for 30 seconds, Compared the quantity of fuel that came out to the chart and it appears that with the pump is flowing what it should.

JoeNova

When we say OS, we mean the one running on the computer. It's typically setup for a 1 bar OS MAF. He would need to flash to a 3 bar OS SD tune.

If the tables weren't tuned correctly for SD, then you will have to completely change them when converting.

If he put the incorrect data in for the 2.5 bar, it won't work right. If the IAT isn't reading after the relocation and rewire, it won't run right. If the MAF DTCs haven't been disabled, you'll have problems. And on and on.

That's why I decided to tune my own stuff. Took a bit to pick up on. So glad that I don't have to constantly return to the same person multiple times to fix and issue neither of us can.

See if he will email you the tune file and a log. Someone here will be happy to look at it.

Hazmatt81

Thanks Joe. I understand there are several variables that can go into the tuning and why something won't run properly or run at all. I will have a conversation with the tuner and see what he says.

Hazmatt81

first start.hpl

second start.hpl

ok all here is a snippet of what the truck does when its initially started.
new to HP tuners so I might have missed a setting or 2 let me know

ss454327

iTrader: (10)

Did you change your O2s?

ss454327

iTrader: (10)

The reason I ask is I just finished an LS1 swap into a 1996 s10 and everything was working in my Camaro before the swap but one first start in the s10 it wouldn't idle and was dumping fuel into the exhaust. My cousin thought it was an issue with the fuel pump and turned out to simply be bad O2s...replaced them and all is right again. I also went from MAF to SD with the swap since I moved to a Vic Jr/4150 TB and more cam.

bgw70

iTrader: (1)

What was the outcome?
Did you ever fix the problem?
It might help someone else.