EFI systems out there. Are NOT all the same.

Bob Dunahugh

New member
Sep 17, 2012
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Carbs that I rebuilt. I tested them on a flow bench. No one does that. That I know of. I don't consider a carb properly rebuilt. Unless the carb is TRUELY tested.
There are some nice EFI systems out there. The GM system that Howell puts together. This system is made up of only GM parts. Except the TB. That's a Holly. I prefer the GM 454 TB. To keep it all GM. That's what I have. It's a self-adjusting system. ( I did put the EBL on it.) It takes about a 15-miles to learn what it's to set itself at. After that adjusting trip. I've never touched it. Ever. The tail pipe is pure clean. You can't get a tissue to have any decolorization on it. ( I have photos that I can send.)
This is the beauty of the GM/Howell.
It has an engine error light. You can walk into any parts store. Plug their Analyzer in to see what the malfunction is. They'll have the part on hand. Back on the road shortly after.
With ALL other systems. You just might end up in No Where's Vill for a few weeks. As you just might need to send your parts into the factory. For repair. It's a great way to destroy a great vacation.
Bob Dunahugh
78 Royale since 2003
________________________________
From: Bob Dunahugh
Sent: Saturday, May 8, 2021 9:44 AM
To: gmclist
Subject: Good engine destroyed. Yours could be next.

I got a call from someone today. That severally damaged a real good running 455. That I built for him 2 years ago. That engine is now trash. When the engine was going in. I pleaded with him to put a GM/Howel EFI system in. His response was. " My carb works great. It's been working to perfection. The carb was rebuilt last year. By someone that knows them well." I should keep my mouth shut on this. As I could go on for days. Over engines. On ways to extend your engines service life. But I'm just sick of this happening. I now know of 4 good engines destroyed in this manner. In the last few years. Engines are my thing. I could post a lot on engines. But it's best that I not. I push GM engines way past their design paramotors. And don't destroy them.

Sorry. I digress. That stock Q jet has always been considered to be one of the finest carbs ever built. As to controlling the air/fuel ratios. Over its entire operating range.
The general though. Is that the carb dumps an air/fuel mixture into an open chamber. That's in the intake manifold. Well. Not really. The Q jet that came on the GMC. Are really two carbs in one aluminum casting. Thus. The left carb feeds 2 cylinders on each side of the engine. The right side feeds the other remaining 4 cylinders.
The problem is that if one side of the carb goes lean. And starts burning up its 4 cylinders. You'll have absolutely no idea of the in pending destruction. Till it's just too late. With the GM/Howell system. The engine check light will come on. To let you know of any issues. Then tell you what's wrong.
Engine service life before the mid 80's was under 100,000 miles. Then in the late 80's. EFI came along. Then service life more than doubled. Yes. Other things that helped. But EFI was the BIGGY. If you wish to talk on this issue. Contact me direct. Not on the net. Or 319-521=4891 Cell.
Bob Dunahugh
78 Royale since 2003
 
I do agree with bob. However the howell and ebl
Sytems are obd1. I doubt most parts stores can read obd1.

However, diy, it is very easy to read the code. Ebl you hook to laptop.

Or you pull up the instructions on use a paperclip and read the blinks of the check engine light.

It does normally run just one o2 on the driver side bank. But the ebl has ability to have a wide band o2 watching both, and display live time on
laptop. The gm based efi was also the only one running a knock sensor.

One of the reasons i installed efi on my rebuilt motor was to help insure not only the investment of the engine, but some piece of mind.

Either way, efi seems pretty nice. If i was
Stuck on a carb, a wide band o2 can easily be added.
--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/