What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Atomic EFI

Chris Ziemer

Chris Ziemer

Daily Driver
 Premium
Joined
Jun 8, 2022
Posts
151
Reaction score
131
Location
Galt CA
Hi all, reviving this Atomic EFI convo. Last thread was from years ago.

Have an 82 K5 w/stock 350. I have endless carb issues between choke and hard starts after being warm. Bought new Quadrajunks and Edelbrokes, but they all give me problems after a while.

Any thoughts on the atomic EFI? This is my daily driver. I’m so perplexed because Quadrajets have been on GM’s for 40 years plus and I feel like I’m the only one under my hood seven days a week. But, I feel like I’m giving up.

Regarding the atomic, I live in California. It’s the only one that is CARB certified.


IMG_8624.jpeg
 
Not trying to be rude. But what about the rest of the engine? Compression, fuel supply and most important, ignition system. The phrase I tell myself whenever I thing I have a carb problem is this:

“80% of carburetor problems are ignition issues.”
 
throttle body EFI kits can be a touchy subject. My personal experience has been that if you don’t buy an EFI specific intake manifold to go with it, or completely and solidly block off the heat crossover on a carb intake with a TBI kit they never run quite right. They aren’t supposed to have heat crossover on EFI/TBI.

I agree that you may have another underlying issue like fuel supply or ignition. Possibly mechanical. You don’t seem to be complaining about stalling at angles off road? Just starting warm? Sounds like vapor lock?

The best aftermarket EFI I ever ran was edelbrock pro Flo 4. That sucker was good. But not cali approved, and was multi port. I tried at least 4 tbi systems. They all ran weird here and there or didn’t perform well across the board.
 
After going down the rabbit hole of aftermarket 2x now this is my opinion .

Holley sniper huge pile of crap . I wrote about it in the injection section .

And now my edelbrock pro flo 4 is so much bettef .

But after both of these i am past aftermarket and back to factory with stand alone harness and flash pcm for it . They spent way more time and money to make it run every day in all conditions .
 
Thanks guys. This partly came about b/c I saw a buddy start his 87ish Blazer after sitting for 2 months and it fired, choked and ran like a beast immediately (factory TBI).
Jealous much? Uh…ya.

Carb problems are primarily hard warm starts. Like with every carb I get (eventually). Much like how some crap under the needle/seat would act. Floods when it sits (off) for even 10 minutes.

Running wise, no complaints (currently have an Edelbrock 600 auto choke on it).

As far as other mechanical issues, not really. I mean #8 boogers up every so often but… factory distributor… no vacuum leaks…
 
Chris Ziemer said:
Thanks guys. This partly came about b/c I saw a buddy start his 87ish Blazer after sitting for 2 months and it fired, choked and ran like a beast immediately (factory TBI).
Jealous much? Uh…ya.

Carb problems are primarily hard warm starts. Like with every carb I get (eventually). Much like how some crap under the needle/seat would act. Floods when it sits (off) for even 10 minutes.

Running wise, no complaints (currently have an Edelbrock 600 auto choke on it).

As far as other mechanical issues, not really. I mean #8 boogers up every so often but… factory distributor… no vacuum leaks…
Click to expand...
If you decide to try the TBI. I’ll just toss in the things that have beat me down with my personal attempts with these swaps. Some of it learned after I gave up on the systems.

Fuel supply, in tank pump is best, it just is. They make k5 tanks for this that may not be a California issue. Get a good pump that will supply your kits required pressure. You want an in tank pump in a baffled tank designed for EFI.

Correct intake for TBI, or an open 1” spacer under your TBI unit and the heat crossover blocked on your carb style intake. Don’t seal the TBI down to a dual plane intake.

Really good o2 install. Exactly as the instructions state. No exhaust leaks.

Follow all the instructions perfectly.

Ask questions on here or reference the injection section. I’m just tossing in my .02 cents of EFI beat downs I’ve had. They all started decent warm and ran at angles off road and were “ok” most the time.

I had an all GM style TBI swap from a place called performance fuel injection systems. But they don’t have a California kit. That was my best TBI kit I ever had. But the parts were all GM. And it had timing control.
 
Last edited:
CharlesC83 said:
If you decide to try the TBI. I’ll just toss in the things that have beat me down with my personal attempts with these swaps. Some of it learned after I gave up on the systems.

Fuel supply, in tank pump is best, it just is. They make k5 tanks for this that may not be a California issue. Get a good pump that will supply your kits required pressure. You want an in tank pump in a baffled tank designed for EFI.

Correct intake for TBI, or an open 1” spacer under your TBI unit and the heat crossover blocked on your carb style intake. Don’t seal the TBI down to a dual plane intake.

Really good o2 install. Exactly as the instructions state. No exhaust leaks.

Follow all the instructions perfectly.

Ask questions on here or reference the injection section. I’m just tossing in my .02 cents of EFI beat downs I’ve had. They all started decent warm and ran at angles off road and were “ok” most the time.

I had an all GM style TBI swap from a place called performance fuel injection systems. But they don’t have a California kit. That was my best TBI kit I ever had. But the parts were all GM. And it had timing control.
Click to expand...
I have a kit from Performance Fuel Injection on my buggy and love it.
 
As always, you’ve given me a lot to think about. In tank fuel pump, baffled tank, intake, heat crossover….some mixed opinions on the unit… the complete kits (fuel pump, sensors, etc…) is 2 grand. I may try another Quadrajet.
I was in the fence with the expense, but figured if it was 2k only and guaranteed success….well maybe.

Couple of you brought up the distributer. Is the factory unit not good enough? It is old…
 
By the way, if anyone is interested, I just ordered some ditch light brackets from the company below. Will let you know how they turn out. For a hundred bucks, I’m expecting perfection. 81-91 Blazer.

squaredinnovations.com

IMG_8943.jpeg
 
Quadra- toilets are not hard carbs to work on. In fact pretty straight forward. As far as carburetors go. Biggest problem I had was the bottom of the mounting surface being not perfectly flat, causing a vacuum leak at the base. I use a bastard file and a straight edge to fix that. Almost every single Quadra-toilet has this issue. And the teflon seals around the horizontal rods that hold the butterfly valves. Most Quadra-toilets leak there too.
Get the right jets for your altitude, and an intact power valve. Then get the float set correctly, even a little low because it’s a 4x4 truck.
Chokes are easy, follow the instructions in the rebuild kit. Set according to your altitude, also.
But, in all fairness, I’ve been working on them for better than 40 years.
Now all that being said, you have to have a sealed intake, no vacuum leaks. Those are the death of many a Quadra-toilet.
And, well like stated above, your secondary ignition parts had all better be in order to. Carburetor issues are hard to diagnose with poor secondary ignition parts grieving you.
But, for stone reliability. Go EFI. You won’t regret it.
 
Last edited:
Grab that $100 dollar summit racing HEI distributor. Throw it in there. And be done with your secondary ignition problems for a while.
 
Chris Ziemer said:
Hi all, reviving this Atomic EFI convo. Last thread was from years ago.

Have an 82 K5 w/stock 350. I have endless carb issues between choke and hard starts after being warm. Bought new Quadrajunks and Edelbrokes, but they all give me problems after a while.

Any thoughts on the atomic EFI? This is my daily driver. I’m so perplexed because Quadrajets have been on GM’s for 40 years plus and I feel like I’m the only one under my hood seven days a week. But, I feel like I’m giving up.

Regarding the atomic, I live in California. It’s the only one that is CARB certified.


View attachment 498636
Click to expand...
I personally prefer oem systems.
I had carbs for 25 years and once I figured them out they are not bad.
But I then got a tbi truck and it was nice for 10 years, literally.
Now I am in the mpfi from the late 90's and early 2000’s and I like them but they are more finicky but better mileage and power.
If you are interested I could set you up with a stock tbi system for cheap. I am not far from you in Lincoln CA
 
Wanting CARB certified implies an inspection county. Will the non-year correct TBI fail or is there automatic CARB approval for OEM stuff?
 
Blue85 said:
Wanting CARB certified implies an inspection county. Will the non-year correct TBI fail or is there automatic CARB approval for OEM stuff?
Click to expand...
It's not automatic but it's more of straight forward.
It has to be newer, offered in the class you want to use it in.
So if you're putting it in blazer it has to be from a 1/2 ton
 
You must log in or register to reply here.

Latest Posts

Top Bottom