LS engine swap info

[sdwolff98]

hmm strong smell of gas during starting attempts. starts with starter fluid. let me ask a mechanic friend of mine and see what he says to check next. hmmm interesting problem the vats disable I am guessing?

sean
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[1sik7t2]

Only thing i know of thats not hooked in the sensors on the exhaust

[Clyde65]

sounds to me like it really isnt getting fuel, have you checked your fuel rail and make sure it isnt plugged? If the engine was out of the truck/van for any length of time, it could have gotten gummed up.

[1sik7t2]

I've cleaned the rails a couple of times...we were wondering the same thing....after tryin to start it, there is fuel on both rails and pressure at the shrader valve turns over, runs with starter fluid, but not on its own...no throttle hooked up but shouldnt need that yet anyway

[68GMCCustom]

I may have missed it......but where the injectors cleaned?

[1sik7t2]

uuuummm cleaned, no blew them out with air, wiped off, rails blown out, what and how should i clean them??? thx p.s. i can see both tiny holes on the end, matters???

[68GMCCustom]

not sure how they are cleaned...just kow there are services out there for it as well as "matching" the injectors for power...but have heard of several LSx builds with used motors that sat for a long time coming across clogged injector issues.

[kSStamp0182]

Originally Posted by 1sik7t2

I've cleaned the rails a couple of times...we were wondering the same thing....after tryin to start it, there is fuel on both rails and pressure at the shrader valve turns over, runs with starter fluid, but not on its own...no throttle hooked up but shouldnt need that yet anyway

Do you mean the throttle body or cable? The MAF MUST be connected and piping ran from it to the TB. Just having it plugged in and hanging there won't cut it if that's how I'm understanding you have it. And id try pluggin in the O2's as well. Did you have your computer's VATS tuned out? That will hinder the injectors from operating.

also, you can test your injectors using an OHMS meter (multimeter). just unplug them and touch the prods to the 2 in the injector. i think the LS1's are 14-16ohms.
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[Shon]

with this ethanol fuel the injectors clog alot easier than they used to, to identify injector problems I lifted the fuel rail and turned it over like I was going to start it, this showed 4 bad injectors. I had used the noid lights and determined they were being told to fire but they were not firing.
Also, if the PCM is set up to run a MAF and O2s that all needs to be hooked up, if its set up for speed density do you have the IAT working? most of these have a 5 wire MAF so you either have to plug in MAF to get the IAT info or pull the wiring for it and wire in a seperate IAT (I use LT1 IATs from Adv Auto).
And we are assuming VATS has been turned off.

[1sik7t2]

well well its was the brand f'n new fuel pump that was bad put another new one in , started right up runs ruff, but runs (1 step forward) wow....thats unusual......so i got hopefully a guy comin this week to help me figure out the rest and wire up everything.....7 @ SHON WHOOOO MAN slow down your talking waaaay over my head.... whats IAT? & VATS?

[sdwolff98]

hey Dave,
Lol that is all fuelinjectionese you are hearing and will need to get used to. as to what he is talking about they are:
IAT: Intake air temperature measure the temperature of incoming air on the engine
VATS: Vehicle anti theft system: integral part of the computer that must be shut off to run these trucks without a coded ignition key
MAF Mass air flow sensor measures the amnoutn of incoming air to adjust the fuel injector spray to get things jess right.



Sean

[1sik7t2]

helps thx no idea on any of this stuff tomorrow i'll look at the brain, see If i can determine what they removed/added thx 4 the help as always

[sdwolff98]

if the truck is running it sounds like it has been removed but never hurts to check that out otherwise might get out of the driveway then die immediately not fun in one of these trucks lol.

Sean

[1sik7t2]

hey wolff, how many quarts of oil these 6 litres take, plus i have the shallower oil pan from the firebird??? & do u know approx how much stays in the engine when we drain the oil?? & what about the tranny (4l80) How much does it hold thx again

Originally Posted by sdwolff98

if the truck is running it sounds like it has been removed but never hurts to check that out otherwise might get out of the driveway then die immediately not fun in one of these trucks lol.

Sean

[sdwolff98]

vortec 6 liter between 6 to 6.5 quarts and trans 4l80 roughly 7.7 if it has not been overhauled or completely drained at any time.

Sean

[1sik7t2]

thx only reason i ask is after runnin it a lil' i drained the engine, only got out 4 quarts, think i put in 5 plus with the shorter pan, it reads higher on the stick....

Originally Posted by sdwolff98

vortec 6 liter between 6 to 6.5 quarts and trans 4l80 roughly 7.7 if it has not been overhauled or completely drained at any time.

Sean

[kSStamp0182]

Originally Posted by 1sik7t2

thx only reason i ask is after runnin it a lil' i drained the engine, only got out 4 quarts, think i put in 5 plus with the shorter pan, it reads higher on the stick....

the fbody pans are 5.5

[1sik7t2]

ok guys looks like the PO had my "brain" played with by fuel injection specialties, i think in texas del VATS/off road/del emissions....6500 rev/no speed./3.08...totally has wrong tire size and gears.....oh boy now what my gears are the 3.83 ...and wheels are 22's...any good news???

[sdwolff98]

Hey Dave,
Should be any problem get into contact with fuel injectoin specialties and see if they can chenge the programming on your gearing and tires size shouldn't be much of a problem to do that.
their contact number is: 210 654-0774
Sean

[1sik7t2]

what problems am i looking at using it like it is tire size would just be the speedometer, correct? but the gears is my biggest concern?

Originally Posted by sdwolff98

Hey Dave,
Should be any problem get into contact with fuel injectoin specialties and see if they can chenge the programming on your gearing and tires size shouldn't be much of a problem to do that.
their contact number is: 210 654-0774
Sean

[sdwolff98]

no it is more than just the speedometer, the engine itself reads data off that transmission that it needs to operate correctly. It changes the shift timing and multiple other issues with fuel mixtures and such. I shouldn't be very expensive to get those parameters changed any tuning shop that uses EFI live or HP tuners can corrent that pretyty quickly for you.

Sean

[1sik7t2]

thx wolff, a wealth of info you are....looking for some 1 here in san diego who can do it.....ANOTHER question.....top of the engine there is )2 cables the throttle and ? whats the other and do i need it? i only grabed the throtte cable thx again

Originally Posted by sdwolff98

no it is more than just the speedometer, the engine itself reads data off that transmission that it needs to operate correctly. It changes the shift timing and multiple other issues with fuel mixtures and such. I shouldn't be very expensive to get those parameters changed any tuning shop that uses EFI live or HP tuners can corrent that pretyty quickly for you.

Sean

[81ShrtBox]

I will need this info....
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[feller]

did not read everything so sorry if i missed it but in a 4x4 can i expect to get better MPG's with an ls or lt swap? someone told me that in a 72 with a 355 and an edelbrock carb that would probably be as good as it gets, but i can not hardly belive that with 6.0's and 5.3 getting 15+ mpg in a new truck it has to get better than an old 355 ( mabey not)

[Firebirdjones]

Originally Posted by feller

did not read everything so sorry if i missed it but in a 4x4 can i expect to get better MPG's with an ls or lt swap? someone told me that in a 72 with a 355 and an edelbrock carb that would probably be as good as it gets, but i can not hardly belive that with 6.0's and 5.3 getting 15+ mpg in a new truck it has to get better than an old 355 ( mabey not)

Absolutely it should do better in mileage.

I can tell you right now, my 72 blazer with it's 355, mild crane cam, performer rpm intake and 750 holley carb, 350 turbo, 3.07 gears and 33" tall tires. I get 13 mpg around town in stop and go. On the highway cruising at 70 mph at 2400 rpms, I get 16 mpg consistently. No overdrive, no fuel injection. Just a good tune and sensable driving.

With the 6.0 (364 cubes) and 4L60E I am certain I'll do even better. For starters, the factory tunes in the trucks are pretty lame, with single digit timing in the tables, etc....it's no wonder the new trucks aren't that great on mileage. All the emissions stuff to run through doesn't help much either.

Also there are a few tricks I can do in the tune to find 2-4 mpg in the part throttle areas. Doing the math,,cruising as 70 mph with this setup is only 16-1700 rpms (I'd like to see it a tad higher) and a gear change may be in order.
In any event, by the time I'm done, 20mpg or more highway isn't out of the question.
I tune my 4th gen camaros, and get 30+ mpg highway out of those with the LS1/6 speed combo.