The Camaro Club (UK)
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Strange Problem
http://classiccamaroclub.mfatw.com/viewtopic.php?f=3&t=4478		 Page 1 of 5
Author:  Yappy [Tue May 12, 2015 10:09 am ]
Post subject:  Strange Problem
Hi guys

I am after a little help and to see if anyone else has had this problem.

When driving my car runs fine put my foot down and she pulls like a train, the problem I have is if I coast to a set of lights or I am in slow traffic were the engine revs are low (tickover) and hit the loud pedal again she starts missing under load. I then raise the revs slowly to gather speed and then she is fine again. If I approach lights and keep the revs up she is fine and pulls well with no misfire.

Now I am thinking it is fuel related like the fuel pump is pulling in air at some point at low revs but when the revs are raised she pulls more fuel then air thus filling the carb.
I have changed the rubber hoses back to the tank and blew out all the fuel lines but she is still doing it, I fear my only other option is to drop the tank and check the pickup pipes.

Just a long shot but I changed the oil to 20W50 could this cause the hydraulic lifters not to work 100% thus causing the misfire

Car Infomation:
327 stock engine 1969 with hydraulic lifters
NEW Edelbrock 4005 Carb
NEW fuel pump
NEW HEI ignition- Totally NEW including the distributor and plugs (ACDELCO R45TS
Already replaced the intake manifold gasket and checked for any air leaks
Oil changed to 20w50
Author:  3rdGenmalc [Wed May 13, 2015 8:26 am ]
Post subject:  Re: Strange Problem
What fuel pump do you have and what is the fuel pressure ?

I think you meant EDL-1405 for your carb, pity you can´t see the fuel level in the bowl on those.
I´m thinking you might have to check the fuel level in the bowl, raise it up.

Do you have the instructions for that carb ?

http://static.summitracing.com/global/i ... l-1403.pdf
Author:  chevy-stu [Wed May 13, 2015 3:27 pm ]
Post subject:  Re: Strange Problem
From my experience Edelbrock carbs in particularly like low (5 or 6 psi) fuel pressure, so if you're not running a regulator it will often bog and misfire..
Mine and my friends vette were both the same until we fitted regulators..
Author:  3rdGenmalc [Wed May 13, 2015 7:22 pm ]
Post subject:  Re: Strange Problem
I started my car up after a long period of rest and it ran odd.
Looked at the fuel bowl levels, Speed Demons have sight glasses, and
the fuel level was at the top of the bowls.
Adjusted the levels to the bottom of the sight glasses.....okay.
Went out for a drive and it ran like a pig, just would´nt run right,
lack of power and surging.
Had another look at the sight glasses and there was NO fuel in there,
I had dropped the level to nothing.
In the end I re adjusted them to where they were before, why the level
rose during the lay over I have´nt a clue.
Just shows how mechanical things hate us.
Author:  Pa's F-bodies [Thu May 14, 2015 9:35 am ]
Post subject:  Re: Strange Problem
OK personally I don't think it's fuel pressure, if you have fuel in the carb then it's in there it doesn't matter at what pressure it came in at unless it was not enough to fill the carb, but that would give you problems when driving fast and the carb would run out of fuel.

Make sure you've got the Vacuum hose for the dizzy connected to the correct pipe on the carb.

Then I would be checking timing and that when you open the throttle watch to see the you are getting full mechanical advance (disconnect or clap vacuum hose to dizzy) then unclamp or connect pipe and see the timing go up again.

if the motor hasn't been rebuilt then your timing chain will be slack which will retard your timing a little, so you can advance it a little over stock. until it sound more crisp or pulls better without pinking and doesn't kick back against the starter when warm starting.

Lastly did you increase your plug gap's when you fitted the HEI dizzy
Author:  Yappy [Fri May 15, 2015 9:34 am ]
Post subject:  Re: Strange Problem
Thanks for all the comments.

I am at a lose with this my head is going messed up as I cannot find the problem.

I would love to be able see in the carb while driving but thats not going to happen. I am sure it is sucking air as everything else has been changed for new parts.
The strange thing is this problem happened immediately and was not over the course of time.
I cannot see it being plug gaps as it was fine for a while before this happened.

New carb, new ignition, new fuel pump and no change.
I will drop the fuel tank this weekend and check out what is going on there, I am hoping that its the sender unit/fuel pickup that is the problem because everything else has been changed.
it feels like a fuel issue and that is the last thing to check.
I cannot keep sitting at traffic lights with my revs at 2000rpm lol
Author:  Yappy [Sat May 16, 2015 4:41 pm ]
Post subject:  Re: Strange Problem
The story goes on,
I dropped the tank and checked the pickup all was good.
When I took the rubber hose off the pickup pipe to the main fuel pipe there was no fuel in it, I now suspect the main fuel pipe, there are no visible leaks though :crazy:
Could it be possible that fuel pump cam is worn??

I am confused with this now :crazy: :crazy:
Author:  3rdGenmalc [Sat May 16, 2015 6:17 pm ]
Post subject:  Re: Strange Problem
Remove the line to the carb from pump, pop it in a bucket and crank.....if the pump cam is okay you´ll see fuel.

When you fitted the pump....err.....you did get the pushrod up out of the way as you placed the pump onto it´s pad did´nt you ?

Before you fit the pump you should turn the motor over by hand and feel the pump pushrod go up into the block as it rides onto the low part of the cam.
Then it´s easier to get the pump on.
Mind you getting the pushrod to stay up is a bugger. :lolno:
Author:  Yappy [Sat May 16, 2015 8:16 pm ]
Post subject:  Re: Strange Problem
Thing is once she has revs she pulls like a train, it's only when I sit at idle and take off.
I will order some fuel line and renew the main fuel line front to rear.

This is the last thing to change so fingers crossed :tired:
Author:  3rdGenmalc [Sun May 17, 2015 10:05 am ]
Post subject:  Re: Strange Problem
Blow the line through with compressed air first.
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