454 cid chevy engine

Reply

  #1  
Old 05-15-16, 05:32 PM
R
Member
Thread Starter
Join Date: Feb 2002
Location: USA
Posts: 86
Received 0 Votes on 0 Posts
Cool 454 cid chevy engine

Its been a while, but I have a new problem. Chevy runs smooth up to 65mph, then it begins to misfire so bad the can shakes. Then increase speed to 70/80/90 it stops missing. Bad injector --or what? Installed new plugs and spark plug wiring--no improvement.

Its all fun!

Thanks

Rebel
 
Sponsored Links
  #2  
Old 05-15-16, 06:19 PM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
Injector? What year is the engine?
 
  #3  
Old 05-15-16, 07:59 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 5 Votes on 5 Posts
454, tells me to check spark advance. How is that achieved, centrifugal or vacuum, or both? And I agree with Pulpo regarding injectors, what year?
 
  #4  
Old 05-16-16, 01:15 PM
R
Member
Thread Starter
Join Date: Feb 2002
Location: USA
Posts: 86
Received 0 Votes on 0 Posts
Pulpo /chandler/Larry

Alright, year is 1991, so maybe the injector was a poor communication. My bad. So, how do I address the spark advance @ 65mph? I have a little analyzer to check if only one cylinder is misfiring. I'll try that if I can find in in the garage

Thanks for the replies.

Its all fun.

Rebel
 
  #5  
Old 05-16-16, 03:19 PM
Rough Rooster's Avatar
Member
Join Date: Feb 2014
Location: USA
Posts: 423
Received 6 Votes on 6 Posts
1991 454 stock distributor is HEI. Check the centrifugal advance under the rotor, Should be able to twist the rotor a few degrees. If not then repair. (requires distributor removal and disassembly) Check condition of return springs and pins. Repair or replace as necessary. Look under rotor for 'burn through' and replace if present.
Check distributor shaft for side to side movement that would indicate worn bushings in distributor housing and/or worn shaft.
Using a hand operated vacuum pump check the vacuum advance for movement and if the diaphragm is ruptured.

When all the distributor problems are satisfied then check module mounted in distributor. (Use a scope while engine is running)

Next look at the coil and see if it shows any burn through signs. Replace if needed.

You should now be able to out"RAT" them all!

Happy hunting!

RR
 
  #6  
Old 05-16-16, 03:58 PM
pugsl's Avatar
Forum Topic Moderator
Join Date: Mar 2008
Location: United States
Posts: 9,004
Received 71 Votes on 64 Posts
HEI distributor Had a problem with rotor burn through but that usually caused a no start. Check for a frayed primary wire, also look at distributor cap for burn marks inside. Have also replaced a lot of modules. Make sure there is not a cheap aftermarket in there.
 
  #7  
Old 05-17-16, 03:33 PM
R
Member
Thread Starter
Join Date: Feb 2002
Location: USA
Posts: 86
Received 0 Votes on 0 Posts
HEI Distribour

pugsl/Rough Rooster:

Thanks for the instruction on the HEI. Will follow the suggestions. Chevy only has 'bout 125k miles logged.

I will post my success or not. Thanks..

Its all fun.

rebel
 
  #8  
Old 06-25-16, 09:11 AM
R
Member
Thread Starter
Join Date: Feb 2002
Location: USA
Posts: 86
Received 0 Votes on 0 Posts
pugsl/Rough Rooster:

You guys earn a star! The HEI rotor was burned and the mechanical advance springs are seriously worn. I will probably just buy a replacement distributor.

Thanks again.

Its all fun,
Rebel
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: