73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: psyguy23 on March 14, 2017, 05:01:01 AM
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Ok, I know how important it is to do a search. I searched and one of two things: either I'm using bad search terms or there are just so many results I'm not going to sift through 68 pages of results. So if there is a thread, please just point me in the right direction.
The Truck:
1983, K1500 4x4, 5.7L
What's Wrong:
It's running, well - hit and miss, eh mostly hit. It will throw a CEL, sometimes, and sputter, choke, stall and restart no problem. This is a project truck. While I could throw a bunch of parts at it, sensors and stuff, I'd rather not. Long term this truck will get a new turn key swapped in it. Until I'm ready for that I still run the truck daily. I have another car but I LOVE driving this truck.
Goal:
What I'd like to learn is what all is involved in pulling all the computer stuff, sensors, O2, flux capacitors and muffler bearings to just have this factory 83 5.7L run on its factory carb and factory ignition setup. Why? Make this truck more reliable by pulling all the tech junk and not have it keep dying on me randomly. I don't know much about this half carb half ECU setup so that's why I'm turning to here. Maybe this idea is just a bad one, maybe it makes sense. Looking to you with more experience to help me figure it out.
Opinions and options are welcome and thanks in advance.
Matthew
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I take it you are not in an emissions inspection state? You can remove the pollution controls, feedback carb, etc and go basic but I would highly recommend you box and save all of your components you remove. Essentially you need an HEI vacuum advance distributor and a non-feedback carburetor.
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Is this a California truck?
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To Stewart and Vile:
I'm not concerned about SMOG checks - even though I live in CA. Wait - how can someone living in CA driving a non-exempt vehicle not worry about SMOG? Well - that perhaps is for another post not to hijack my own thread. Essentially go on to DMV website, find exempt places in CA and register your car there. Totally legal, totally awesome, and totally something all car guys in CA should know. But I do appreciate the smog advice none the less.
To Vile: It seems like the answer was a yes. I am mostly concerned about the factory quadrajet. I have no experience with this carb and how dependent it is on the ECU for inputs/vacuum/magic. Do you know of any threads or places I should go read up on so I might tackle this on my next days off?
Thanks for both the replies.
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i don't think a CCC carb will run very well without the computer (see Doug Roe's Quadrajet book). So you'll need a a new/different/reman q-jet.
Also, you won't have any vacuum advance on the distributor(not even sure if you have mechanical advance either?), so you'll need to replace it with a "conventional" HEI distributor. Anything from the salvage yard for a 74-80 chevy small block should work. GM performance has them as well. AC delco should have remans available.
As far as jegs/summit. ONLY get GM performance/MSD/ Pertronix etc.
The off-brand, offshore stuff is to be avoided. I.e., Skip White/ebay stuff.
Most of the chapter on CCC carbs is online here, i think?
https://books.google.com/books?id=DwUMAaiyMoYC&pg=PA58&source=gbs_selected_pages&cad=3#v=onepage&q&f=false
i'm not saying to definitely buy this carb, but i run it on the 4.3 and it does ok. i would be willing to bet it would run good on the 350:
http://www.jegs.com/i/JEGS-Performance-Products/555/15805/10002/-1
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I would not recommend junk yard parts. New or Reman parts are readily available rather inexpensively. Also 74 is a breaker points distributor so use a 1975 application.
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Thanks Stewart for those references. I will read up regardless. Getting good sources is half the battle.
Sounds like both are confirming what I suspected: to pull all that equipment I would need a different carb and ignition. Not a great option since all will be pulled eventually. So for the mean time it is on to diagnosis and troubleshoot. At least now I know troubleshooting is my only real option.
I'll read that material and then figure why the truck keeps sputtering and stalling along.
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I would not recommend junk yard parts. New or Reman parts are readily available rather inexpensively. Also 74 is a breaker points distributor so use a 1975 application.
i meant that if the junkyard was used as an option that you should check the unit out and rebuild it if necessary. Since the OP seems new to this, perhaps this is not a good idea.
b) i meant that i think the corvette had HEI in 74---and then everyone else got it in 75. So to be simple, 75-80 should work, although 75-78ish may have a better timing curve than 80 due to emissions? (maybe?)
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Since the OP seems new to this, perhaps this is not a good idea.
You sir - are correct. The silly part about it is I can jump in an EFI forced induction vehicle and map fuel and timing on a laptop. But the simple world of fuel, ignition, vacuum - new and learning. I'm looking forward to it though.
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These may help:
http://performanceolds307.tripod.com/id1.html
http://www.early3rdgen.com/forum/viewtopic.php?t=25
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I personally would find out exactly what is wrong before going through all the trouble of removing everything. It could be something simple and have nothing to do with the computer stuff.
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AFAIK GM was not using a computer in square body trucks in 1983, so where did your engine come from? You may have some electric controls for your Quadrajet, but I did not think they were controlled by a computer. Or am I confused about when computer controls came in for these trucks?
Bruce
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I have a '83 K10 305, sold into the Texas market. My own has a regular, non compuper controlled HEI and was retrofitted with a Edelbrock 4 bbl carb. Perhaps the California '83 had a more advanced computer controlled smog system, but my computer was put out to pasture years ago, truck runs great.
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The reason I asked about the computer is that it would be helpful to know what kind of frankentruck we are dealing with. If someone retrofitted a newer engine (with computer) to an '83, they may have missed a few things in the conversion, which may be the source of the current problems.
Do you know what systems the truck had originally, and how much of the current setup is modified/new? If you want to leave the controls installed,, then you need to understand what you have so that you can fix it.
If you simply want a non-computer, non-electronic, carbureted truck, just take off all electronic controls and/or EGR off and install the 1406 carburetor and a stock large-cap HEI.
Bruce
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i believe california trucks were required to have CCC---Computer Command Control. (At least 1/2 tons or below 8600 gvwr. Then again with California......who knows...) All other state's trucks did not.