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#1 |
Registered User
Join Date: Mar 2000
Location: Lake Jackson, TX.
Posts: 1,930
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ok check this idea out
well the clatter problem aint totally fixed, yes i am pissed. but, i got an idea what it could be. he other day when i had the top of the carb off, i noticed the fuel level was below the slosh plates. you know the plates the keep the fuel so the secondaries are fed. well i raised the float level and it fixed it a bit but the clatter is still there at WOT. well today i was at a buddy of mines and we check the total timing. its 28 total at 3,000 rpms. (8*btdc +20*centrifigal) ok thats text book. well as i was reving the engine, i noticed the fuel filter was not filling up, in fact there was very little fuel retaining in the filter and this was after i let it back to idle. so, here i go again, we checked the fuel pressure and it was about 6.5 psi. right thats about normal. well here is my question. is it possible the fuel pump can be weak and not be able to keep up with the demands of the motor drawing the fuel at WOT. i am thinking about changing the fuel pump, but was wondering what yall thought about ths therory.
PRAYERS for THE PASSENGERS AND PILOTS OF THE COLUMBIA
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2004 Silverado Crewcab (Dark Spiral Gray) |
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#2 |
Registered User
Join Date: Mar 2000
Location: Lake Jackson, TX.
Posts: 1,930
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^^^^^^^^^^^^^^
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2004 Silverado Crewcab (Dark Spiral Gray) |
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#3 |
You get what you pay for
![]() Join Date: Dec 1999
Location: Cherryville, NC
Posts: 4,798
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I guess anythings possible. If you have 6.5 psi at idle, I doubt you are running out of gas at WOT. It if was, you would sure be able to tell it by the way it ran.
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Mike 1985 Chevy C-10 |
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#4 |
Workaholic
Join Date: Oct 2002
Location: Katy, TX
Posts: 1,589
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Actually, yes. Hotrod handbook indicates that you should have fuel pressure of 7 psi @ WOT-any less and you could be losing performance. BTW, carb, not efi.
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1979 K-10 Silverado (work in progress) 1991 V1500 Subruban 1999 Suburban LT 4x4 2006 Suburban LTZ (daily driver) |
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#5 |
BAD BOW-Silverado XST
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
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Change the pump. No major problem and good assurance than having an old pump.
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#6 |
I'm back with 2nd truck!
Join Date: Feb 2002
Location: Texas
Posts: 3,775
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I agree. Chenge the pump and look to see if it makes a difference.
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1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson |
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#7 |
You get what you pay for
![]() Join Date: Dec 1999
Location: Cherryville, NC
Posts: 4,798
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I think changing the pump is a waste of time and money, unless it's falling on it's face at WOT. Although, it is pretty cheap and would be one more thing off the list.
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#8 |
Registered User
Join Date: Jan 2003
Location: Guntown,MS
Posts: 172
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In my RX7 I had the same problem. Whenever I hit the gas it wouldn't accelerate and would chatter real bad. Replaced the pump and the problem went away.
AJ |
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#9 |
Registered User
Join Date: Mar 2000
Location: Lake Jackson, TX.
Posts: 1,930
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i replaced the pump yesterday. i will see if that fixed it today, i other thigs to do yesterday. i am thinking this may have been the problem, yea how many times have i said that LOL. anyway, im thinking it wasabout to go south, i could smell fuel in the oil where the pump mouts but i may have been smelling what leaked out. anyway, it was time to change that because it was off the old tired 305 with 180,000 miles that i took out about 5 years ago. i know this cause i didnt replace it and the 87 BURB this motor came from was fuel injected and didnt have a mechanical pump.. it seems better and the fuel filter is about 3/4 full all the time. i'll keep yall posted . i will be excited to be able to set my timing at 12* initial, it runs fantstic at off idle and part throttle at 12*.
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2004 Silverado Crewcab (Dark Spiral Gray) |
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#10 |
You get what you pay for
![]() Join Date: Dec 1999
Location: Cherryville, NC
Posts: 4,798
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Good luck with it Jeff. I didn't realize the pump was this old. You done good by changing it then. One things for sure, it won't hurt nothing.
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Mike 1985 Chevy C-10 |
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#11 |
Registered User
Join Date: Mar 2000
Location: Lake Jackson, TX.
Posts: 1,930
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well it didnt help what i wanted, well sorta. it did get rid of some of the clatter but the timing is still set at 8*. my next step is to put another distributor in it. the guy that has the wrecking yard is gonna give me one. i did notice while looking at another one the difference in the center shafts. this one i was looking at had ears that came off the advance plate and the slots did seem smaller. now this could be my mind playing tricks, but if the slots are smaller then that would limit my total advance and thus FIXING MY PROBLEM and then be able to set timing at 10-12* oh well back to the drawing board. just think how good its gonna run when i do get it right, i have been through everything else
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2004 Silverado Crewcab (Dark Spiral Gray) |
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#12 |
Account Suspended
Join Date: Nov 2002
Location: Winnipeg, Manitoba, Canada
Posts: 798
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Sorry to hear the bad news, Jeff. I don't have any advice, but have been following your saga for interest sake.
Hope things turn around soon. ![]() ![]() ![]() |
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#13 |
You get what you pay for
![]() Join Date: Dec 1999
Location: Cherryville, NC
Posts: 4,798
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Never give up. You will get it one day for sure. I just can't understand it myself. I bet when you do finally fix it, it will be something fairly simple.
Good luck.
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Mike 1985 Chevy C-10 |
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#14 |
Registered User
Join Date: Mar 2000
Location: Lake Jackson, TX.
Posts: 1,930
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yea and it will help out another. this other guy has been having the same problem but in a van.
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2004 Silverado Crewcab (Dark Spiral Gray) |
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#15 |
Account Suspended
Join Date: Nov 2002
Location: rayville,LA
Posts: 226
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put a pickup coil and advance weight kit in your distributor. they dont cost but $7 at the most, much cheaper than new one. i had a 305 i just rebuilt ,had 2000mi on a rebuild and it started rattling. it sounded like weak mains but it wasnt. i got in it one day, it fired up and went dead, that was it! i towed it home, put a pickup coil in it and weight kit and it ran like a new one. just my 2cents
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#16 |
Senior Member
![]() Join Date: Dec 2002
Location: Portland, Oregon
Posts: 901
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Not as simple as just putting in a advance weight kit....Every engine has specs for the advance curve ( amount of degrees advance per specific RPM.). Only a shop that has a distributor machine ; enabling the installation of the proper weights and springs combination to achieve desired specs.....Also the vacuum advance must operate in the appropiate RPM range....
For example; GMC Shop manual for my '71 402 BB is (degrees) ---- 0 @ 930 RPM; 2 @ 1260 RPM; 16 @ 2400 RPM and 30 @ 4400 RPM. The vacuum advance should be 0 @ 8" h.g and 20 @ 17 h.g Another GM manual shows the the total ( centrifugal and vacumm) advance should be 28 to 35 @ 2000 RPM... So, when installing the calibrated HEI distributor; I set the timing lite at 33 degrees, engine@ 2000..... and have been quite satisfied with engine performance andf fuel mileage...... I don't pretend to be an expert in all this but the distributor shop did stress the importance of maintaining factory specs ... ..........Made sense to me............
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'71 GMC;fleetside;PB/PS/AC/CC/402 Eng./Custom Paint/110,000act miles/3 fuel tanks(52gal). |
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