LS engine swap info

[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

[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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[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.

[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

[feller]

hummm... thanks man

[89 crewcab]

what swap would get me the most bang for the buck in a 1989 3500 4x4 crew cab RV puller? I like the Cummins idea but that = mucho $

[Firebirdjones]

Are you looking for pulling power or gas mileage??

When it comes to both, it's hard to beat a turbo diesel. I just can't justify the cost so those are out of the question for me.

I use a 79 1 ton for pulling my 28 foot enclosed. The 454 was getting tired so in my case it made more sense to rebuild with a stroker crank (aka 496).
The old 454 would get 14 mpg highway with 3.73's and a 400 turbo. I lost some of that with the 496 but I was after more towing power for the hills around Arizona. It's all a matter of what is more important to you.

[89 crewcab]

It has a small block 5.7 stock engine now, best of both worlds. You know, no power AND bad mpg's. I dont expect to get better mileage out of a stroker (383) or a big block but my 30 ft toybox only allows 25 mph on some grades with the stock engine. I have heard a lot of praise to the 383, but how much more work/money would it take to swap to the 496? I have a turbo 400 trans in it now but I also have a Getrag 5 spd I could have swapped in. I am looking for pulling power more than anything, but dont want to get too many $ wrapped up in it.

[Firebirdjones]

Hmm, I'm surprised an 89 3500 crew cab would come with a 350 for an engine.

Swapping to a bigblock is a pretty big chore if you don't have a donor truck to start with. Every bracket and accessory is different, that's not even getting into all the computer controls and tuning differences.

My old 79 is a factory 454 1 ton, so it was already there, when it was time for a refresh the 496 stroker just seemed like the next logical step for me

If I were in your shoes and didn't have a donor truck to steal from, I'd stick with the small block package and maybe look at some of the crate engines like the HT383. Or if you know of a reputable machine shop then stroking the 350 to a 383 is cost effective. Actually it's about a wash when it comes to rebuilding one anyway. That's probably the least expensive way to go if you dont' mind some down time.

[89 crewcab]

thanks for the reply, I wondered what was involved with the big block swap. Do you have to change fuel delivery when you go to a 383 or will the tbi that is on it now be sufficent?

[Firebirdjones]

I tune carbs and newer LSx fuel injection stuff, but the throttle body stuff is an older design that uses a computer chip and completely different software.
I used to tune tuned port injection stuff which used that software made or sold by Moates, of which I no longer have.
At the very least you would have to find a place that can reflash your E-prom so it's more suited for the fuel and timing requirements of the 383. Other than that, in a nutshell what you have should transfer over and work.
TPIS is one place that comes to mind. Arizona Speed is another. They both still tinker with E-prom style computers as well as design and build intake and fuel systems for this style fuel injection.

[thor]

Just tossing out a different idea - How about lower gear set for the TH400? Many manufacturers make a 2.75 first gear and 1.57 second gear for the TH400, as well as the 4L80e. This could get your mass moving better. But, if it's cruising speed your after, then I agree, you need a heart transplant.

A stroker motor would be the cheapest and easiest route since you already have a small block in place. However, big block will give more grunt. A 454 would probably be the next "cheaper" step, but like stated above, it would be easiest to find a donor vehicle for all the parts you don't think of until things don't line up quite right. But to tempt you even further, perhaps an 8.1L would be fun. A 496 with fuel injection from the factory. But I think we've blown the budget by now. So back to the 383.

Just my .02

[89 crewcab]

I thought of the 8.1 but would'nt you have to intall a computer or something?

[thor]

Yes, you would. And that brings other headaches, challenges, or opportunities to learn new stuff, depending on your outlook. I'm also not sure what the "recyclers" are wanting for them. Easy + cheap = 383, me thinks.