Carb issues... Injection swap maybe?

[AcIdBuRn02ZTS]

Hey alls... Not sure if im in the right place or not... but here it goes...

I'm new to the forums and am looking for some help..

I own an 83' K10 stepside... list of mods as follows...

-Motor-
Post 86' 4blt block (punched .040 over)
Hypereutectic Pistons (std. comp. ratio)
bottom end fully balanced
98' vortec cyl. heads hand ported/polished
comp cams 260H-10 cam kit
alu. 4bbl vortec intake (world products i believe...)
holley 670 truck avenger carb
stock HEI dist.
flowtech tri-y headers
2.5" header back exhaust all mandrel bent

-Tranny-
TH350 fully built w/ B&M racing overhaul kit & transgo full shift kit
B&M 2500 stall converter

Not sure about gear ratio's... havnt had the diff's open to check things out as of yet...

im running 35" rubber if this makes any difference...

now my problems.... first... ive been through 3 carbs on this motor and i keep running into flat spot issues. ive had 2 edelbrock 600's on it... both of which would eat the 35's up... until one day i started noticeing flat spots... so i figured dirty carb... (btw.. truck had new 31 gal blazer tank mounted under bed and all new lines and pump) so i pulled the carb apart... fully rebuilt the carb... put it back together and it ran great... couldnt keep the tires stuck to the pavement... for about 1-2 miles... then it would be back to the same flat spot, horrable acc. crap. hooked up an a/f gauge and found out i was leaning out quite a bit when coming into power.... tried tuning the carb w/ new jets.. rods... nothing worked... called edelbrock and they said the carb would not perform properly based on my engine... so i swapped out to the holley 670 truck avenger. noticed horrable flat spots.... same leaning out bull crap... and not to mention the 5mpg average fuel mileage... did a little tuning on the carb... helped a little but still sucks gas and wants to die if i step in it hard then let off the pedal suddenly... im also running a summit fpr set dead on at 7psi which is what holley suggested i do...

im tired of the carb crap and continious problems... and horrable fuel mileage.. so im wanting to go to fuel injection. i know the vortec stuff will bolt directly to the motor without issue... so im wanting to know what kind of tuning will need be done to the ecu to make things work properly... if any? the only thing i can think of that would not allow the truck to run with a factory vortec ecu would be the cam...

my other route would be the holley pro-4 tbi setup...

any suggetestions or perhaps could someone tell me what is going on w/ my current setup before i do all this work?

Please help out if you can.
thanks
-AcId-

[modular93fox]

well you could just get a new FI motor/trans for the price of an efi intake kit. average 5.3 and 4l60e with all the fixins goes for 1800-2000 and im sure you can jew a transfer case out of them.. thats one way to solve the problem.
clint

[EWC]

I put a Holley TBI system on an Olds Cutlass with a built 455 street engine when they first came out . Throttle response was great . While that is one way to go , I can't help but think that if you found a good carb shop you could get the carb set correctly . I'd also want to find out what gears you have . Most of my work has been with the older Holley carbs , 4150 , 4160 and a little 4500 dominators . The vac secondary carbs are at least tuneable with the different springs . The lean condition you have may be cured with some tuning and time . Might get so info from all the carb books that are out there . Some of the better shops are listed in the car mags or National Dragster . Good luck .

[trickedout420]

im running the retrotek speed FI unit, and i LOVE it, i had the same problems with carbs and couldn't figure it out so i bought this and havent turned back since. only $2600 for everything needed and they even tuned it to my motor for me.

www.retrotekspeed.com

[AcIdBuRn02ZTS]

fuel mileage is also a huge issue... i can hardly afford to drive the truck anymore...

another reason why im considering fi...

another weird deal is... when coming into power... it leans out... but it runs rich the rest of the time...

ive been strongly considering a full 2500hd drop out... meaning H.O. 6.0 w/ 4l80e... and transfer case if im lucky... dont know though... the motor in the truck now has less then 10k on the clock and is the first motor i ever built (started building the motor when i was 12... dumped nearly 5k into it with all the machine work and the high dollar bearings/rings and what not.. (probably not needed.. but I was younger and thought it was worth it at the time...) took me up until i was 16 to finish the motor (mowing grass and little odds n' ends jobs take forever to make that kind of money...) swapped the motor out in 3 days which included me overhauling the transmission myself (which was also a first for me..) and now it sits most of the time cause i cant drive it... its pretty annoying...

i like the looks of the stuff from retrotek... looks pretty unique compared to most efi solutions ive came acrossed....

hmm...

-AcId-

[Old88]

Get a fuel pressure gage that you can see at WOT.

[GreaseDog]

looks to me like your setup is mild enough for a tbi system. you should be able to scrounge one up at the JY or someone who is parting out a tbi truck or has an extesive stash of vintage Chevy/GMC parts... maybe somone in your state has one...

[EWC]

I still think you could tune the carb better . Is this the carb that Holley thinks will work for you ? Did it ever backfire ? I just Googled the Holley Avenger 670 and they have a tuning sheet online . One of the carbs listed has a power valve of 25 , very low vacuum rating . They can be interesting to tune .

[AcIdBuRn02ZTS]

i hooked up a vac. gauge and installed the proper power valve.. which helped... but it still leans out a bit...

the fuel pressure doesnt ever leave 7psi... so no issue there i believe...

and i have a complete tbi setup in the garage.. but from what ive read... its difficult to tune for the head and cam combo... the base tune on the stock ecu wont work properly (from what ive been told)

i wouldnt mind keeping the carb... i just need to get it dialed in to operate properly and get better fuel mileage hopefully... no carb shops in the area though...

any suggestions as for tuning the carb or what i should do? could it be ignition related?

-AcId-

[AcIdBuRn02ZTS]

I contacted holley and they say its the power valve... and told me how to properly select one... so perhaps in the next few days.. i'll get a good vac. reading and get another valve on the way...

we'll see what happends...

-AcId-

[Koots]

Originally Posted by modular93fox

and im sure you can jew a transfer case out of them.. thats one way to solve the problem.
clint

I Can't believe no one else noticed this. Almost slipped under the radar

[GreaseDog]

i noticed it, just didnt really register as anything out of the ordinary.

[Koots]

I thought it was funny.

But continue with the thread, sorry for the speed bump.

[soon2b_bagged]

I have a 85 K1500 with a GM crate 350, quadrajet carb. Would the TBI from a 94 G20 van with a 350 work on my engine. I have the whole van so I can get the ecm out of it if needed.

[GreaseDog]

yes it would work, but you'll need the ECM reprogrammed to run whatever trans is in the truck, since it will be trying to electronically shift the 4l60E that's supposed to be behind it. brackets for the TV cable (if equipped) will need to be located. shouldnt be that bad of a swap though really.

[soon2b_bagged]

The van has a 4l60e and my truck has a 700r4. Wouldn't the TV cables be in the same place on the transmission, and pretty close to the same place on the throttle body?

Let me know if I should start my own thread about this topic.

[GreaseDog]

they would... if the 60E used a TV cable, but it doesnt.

[soon2b_bagged]

I knew that, but I don't know why I forgot. The 4l60 has a TV cable doesn't it?

So I would need a linkage to put on the throttle body for the TV cable. Since I took the cruise control off my 85, could I use that linkage for the TV, or is there a "push pull" thing that won't let it work?

[GreaseDog]

depending on where the stud is. TV cable geometry is pretty precise, especially if you want your trans to last.

[soon2b_bagged]

Does anyone make a bracket that could be used for the TV cable, or is that something I would need to fabricate. It shouldn't be too hard to make something, as long as I can adjust the TV cable for the new stud location.