Having Issues with Holley 670 Street Avenger? Let's Troubleshoot!

Questions and Support
1

Introduction

If you’ve installed the Holley 670 Street Avenger on your Chevrolet and are facing some issues, you’re not alone. Many enthusiasts encounter challenges with this carburetor during installation and while tuning for optimal performance. In this post, we’ll break down some common problems and troubleshooting tips to help you get back on track.

Common Problems

  1. Poor Fuel Economy: Many users report that their vehicle’s fuel economy drastically decreases after installing the 670 Street Avenger. Here are some possible causes:

    • Incorrect float level settings
    • The power valve may be opening too soon
    • The main jet may be too large

  2. Engine Stalling or Rough Idle: If your engine stalls or has a rough idle, it could be due to:

    • Vacuum leaks around the carburetor
    • Incorrect idle mixture adjustments
    • Insufficient fuel delivery from the pump

  3. Hard Starting After Installation: A common complaint is difficulty starting after installing the carburetor. Possible reasons include:

    • Improper choke settings
    • Fuel line issues
    • Possible flooding during startup

Troubleshooting Tips

  • Check Float Level: Use a sight glass or a clear tube to check the float level, ensuring it’s set according to Holley’s recommendations.
  • Adjust Idle Mixture: Start with the engine running and gradually adjust the mixture screws on both sides to achieve the best idle quality.
  • Inspect for Vacuum Leaks: Use carb cleaner or a smoke test to find vacuum leaks which could be causing unstable idle issues.

Seeking Advice

If you’re still having trouble after trying these solutions, don’t hesitate to ask for help. Please provide details about your setup (engine specs, other modifications, etc.) along with any symptoms you’re experiencing. The more information you provide, the better the community can assist you!

Conclusion

The Holley 670 Street Avenger is a great choice for many Chevy engines, but it can come with its quirks. By addressing common issues and reaching out for advice, you can optimize its performance and enjoy your ride. Let’s hear your experiences and any additional tips you might have!

2

I’ve been having some serious stalling issues with my Holley 670. It seems to happen mostly when I come to a stop. Has anyone else experienced this?

3

I feel you! My Street Avenger also stalls at lights. It’s so annoying! What adjustments have you tried?

2 Likes
4

One common problem with the Holley 670 is that it may be running too rich or lean. It could be worthwhile to check the jet sizes and adjust the floats accordingly.

5

That’s a good point. I adjusted my jets last week, but I still feel like the acceleration isn’t smooth. Any tips?

6

For uneven idle, check if your air-fuel mixture screws are properly adjusted. Sometimes they get overlooked but can make a significant difference.

3 Likes
7

I’ve tried adjusting the mixture screws, and it helped a bit with the idle, but the acceleration is still lacking. It feels like I’m dragging a trailer!

8

Haha, I can relate! Have you checked your ignition timing? That can often affect acceleration too.

9

I had a similar problem when I first installed mine. Turns out it was just a loose vacuum line causing the performance issues.

10

Yeah, vacuum leaks can be sneaky! I’ve checked mine but not recently. I’ll make sure to double-check all connections this weekend.

6 Likes
11

Good call! And don’t forget to look at the gaskets; sometimes they just need to be replaced after a while.

12

I wonder if anyone else has noticed a difference with aftermarket performance parts? Thinking about upgrading to improve overall performance.

13

I’m having some real trouble with the jetting on my Holley 670. It backfires occasionally, so I think it might be too rich. Any tips on where to start adjusting the jets?

14

Have you checked the idle mixture settings? A good starting point is to turn them in until they lightly seat and then back them out 1.5 turns. That could help with the richness!

15

Float adjustments can also mess with how it runs. If your floats are set too high, it can cause flooding. Check that as well!

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16

I adjusted mine after reading similar advice, and it really made a difference! The engine responded much better after I got the floats set right.

17

What kind of symptoms are you seeing with your tune? My friend had similar symptoms, and he just needed to adjust his idle speed. Sometimes it’s the little things!

18

I’m curious, what jets are you currently using? It really helps to know that, especially if you’re in a higher altitude area. Adjustments can vary significantly!

19

I’ve got 65s in mine, but I think I need to go up to 68s. Does that sound right based on your experience?

20

Honestly, the Holley 670 has its quirks, but once you find the sweet spot, it’s pretty solid! It just requires some patience during tuning. Keep at it!