HomeHome  PortalPortal  CalendarCalendar  GalleryGallery  FAQFAQ  SearchSearch  RegisterRegister  Log in  

Share | 

 olds 455 question

Go down 


Posts : 5443
Join date : 2008-11-04
Location : Palm Beach County

PostSubject: olds 455 question   Mon Nov 07, 2016 9:38 pm

for all you old timers.

If you recall a few months ago, I got a new elctronic whatchamacallit in the bottom of the HEI distributor (for the life of me can't think of the proper name right now, but you know what I mean). At the same time a new cap and rotor was put on. My friend 'did me a favor' and messed with the timing. Well it was waaay retarded and ran like ****. He also mentioned that he found a vacuum hose disconnected and reconnected it.

After advancing the timing it runs better but not as good as before. Gas mileage is off by about 15% (or 1.5 mpg as I was getting 9 on the highway before and now 6-7) which is better than the 4 I was getting. It still feels boggy off the line and the exhaust is black and sooty.

1 what vacuum line might be in play here BESIDES the distributor vac advance (seems to be ok).
2. besides the timing and new parts he says he didn't mess with the carb

I'm taking it on a 350 mile trip this weekend with minimal time to work on it prior to leaving....she runs ok but is sucking up fuel too fast and not as peppy as she should be.
Back to top Go down

Posts : 41
Join date : 2016-01-05

PostSubject: Re: olds 455 question   Mon Nov 07, 2016 10:12 pm

Does the engine have a egr valve? If so check to make sure it is connected to a ported vac source- no vac present at idle .are the advance weights in the dist siezed? Common issue . Was there a fine rust colored film inside old cap? Could be a sign of the advance weights wearing thru there pivot pins =not good, they can sometimes hang up when worn good luck hope this helps
Back to top Go down
phantom 309


Posts : 5797
Join date : 2008-12-28
Age : 109

PostSubject: Re: olds 455 question   Mon Nov 07, 2016 10:29 pm

Hard to say or diagnose over the internet,. but to get that low a fuel mileage i,d say you are into the throttle pretty good,. which depletes vacuum which may retard timing etc,. etc,.

make sure the choke lockout lever isn't holding the secondary airflaps closed,.

A cheap vacuum gauge would be your best friend,.

Set the timing advance with the vacuum advance hose disconnected,.
post some pics of your vacuum hoses,.there are different combo's for vacuum advance ,. ported vacuum,. plenum vacuum etc,..

black and sooty is a paris hilton tune,. rich and retarded

You could try a quick experiment,.pull the cap,. pull the rotor, remove one of the advance springs ,. see how it goes,.if it starts pinging put it back on,.

run pure gas no ethanol,.for s+g put a can of octane boost through it see what happens,.

It's a module you replaced,.
Back to top Go down


Posts : 2508
Join date : 2009-06-14

PostSubject: Re: olds 455 question   Tue Nov 08, 2016 2:01 pm

Going from memory: HEIs need to be timed with a certain electrical connector unplugged. Confirm with a google, of course...
Back to top Go down


Posts : 5443
Join date : 2008-11-04
Location : Palm Beach County

PostSubject: Re: olds 455 question   Tue Nov 08, 2016 6:58 pm

OCC, didn't see the old cap, the work was done by a guy with 20+ years on these motors (not to say he didn't get distracted or something).

309: Paris hilton.....you a funny guy, I LOLed

Jay: we set the timing by twisting the cap while I was driving up and down the street. My buddy stood behind me and changed it as I kept flooring it up and down his street. It was fun. I do have a light and will do a proper timing after the new plugs and wires (won't have time b4 the weekend though).

Thanks guys, have given me some things to check when I pull the beast out to prep for the trip.
Back to top Go down
Fred Kiehl


Posts : 4955
Join date : 2009-11-13
Age : 70
Location : Largo, FL 33774

PostSubject: Re: olds 455 question   Thu Nov 10, 2016 7:26 am

The part is the ignition module. If it has a cat, all of the rich running may have clogged the cat.
Back to top Go down
Sponsored content

PostSubject: Re: olds 455 question   

Back to top Go down
olds 455 question
Back to top 
Page 1 of 1
 Similar topics
» Question about forum securities?
» Credits question?
» Question on private forum
» A question of my
» Founder & Founder Utils question

Permissions in this forum:You cannot reply to topics in this forum
GM Longroof Forum :: Longroof Tech :: Engine-
Jump to: