Author Topic: Engine Struggle  (Read 10029 times)

Offline dphipps

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Re: Engine Struggle
« Reply #15 on: August 05, 2017, 05:52:59 PM »
I think you should wire the choke properly or remove it. I think I would also verify the float level is correct.

Offline Irish_Alley

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Re: Engine Struggle
« Reply #16 on: August 05, 2017, 05:55:23 PM »
also i live in maryland. with this weather we're having choke shouldnt be an issue unless its "on"
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Offline Johnbravado

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Re: Engine Struggle
« Reply #17 on: August 06, 2017, 10:07:31 AM »
accessories nothing really, i believe it is referred to as short block, everything i bought new like intake, fuel filter, water pump, flex plate, carb.

I am not sure if this was the issue, but there is a manifold vacuum port coming off the rear of the intake. It is a splitter, 1 of the lines goes to the transmission, i think based on what an earlier person was saying of things to check, it goes down i 'trace it out. the other one wrapped around and would connect to my distributor if i used vacuum advance to time the engine, but engine spec says don't do that and so it was left uncapped.

truck was sounding like garbage, when I plugged the line it picked up and sounded good, released and sounded like garbage. plugged sounded good. So i redid the timing and set the carb and will see how it goes.

and i appreciate the help from everyone.

Offline Irish_Alley

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Re: Engine Struggle
« Reply #18 on: August 06, 2017, 03:35:20 PM »
ok, did it come with a timing cover and harmonic balancer? the vacuum lines, cap all that arnt being used. the trans and vacuum advance should be manifold vacuum and the brake booster. when you set timing unplug the vacuum advance and plug that line. ensure you have NO vacuum leaks
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Johnbravado

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Re: Engine Struggle
« Reply #19 on: August 06, 2017, 04:52:58 PM »
I believe I had to buy a harmonic balancer for it because we were going to use the one off old engine but the guy sold it to me lies and said it was a 350 and in reality it was a 305. The only thing right now that could possibly be giving a leak now is the old fuel carbon canister but I replaced all vacuum lines.. and thanks for the info on the no need of choke.

Offline Irish_Alley

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Re: Engine Struggle
« Reply #20 on: August 06, 2017, 05:12:55 PM »
you said you left one of the manifold lines uncapped ("he other one wrapped around and would connect to my distributor if i used vacuum advance to time the engine, but engine spec says don't do that and so it was left uncapped. ")

theres also three locations for the timing marks




http://www.crankshaftcoalition.com/wiki/Timing_tabs_and_damper_TDC_lines_SBC
the only way i know to tell if you have the right setup is to manually bring the piston up to TDC and see where the mark on the balancer lines up with the timing cover.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=32085.msg270456#msg270456
« Last Edit: August 06, 2017, 05:29:25 PM by Irish_Alley »
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Johnbravado

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Re: Engine Struggle
« Reply #21 on: August 07, 2017, 07:42:27 AM »
i am going to have to recheck my timing. i have the cleaner looking silver bracket. except it is real hard for me to see things down there but your picture cleared it up. I don't think it is timed right now. I think it is timed to 4* instead of 10*. thanks a lot for the picture. I will have to look at it again when I get home after work.


Offline blazer74

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Re: Engine Struggle
« Reply #22 on: August 07, 2017, 05:06:31 PM »
I'm going to have to say if your timing was off enough to cause it to run that poorly you would be causing the engine to run hot.

You said sometimes it accelerates fine then it doesn't.

Sure sounds like a loose baffle in the exhaust moving around sometimes  blocking the exhaust flow

Shot gunning the brake booster seems like an expensive shot in the dark unless I missed something.

Online VileZambonie

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Re: Engine Struggle
« Reply #23 on: August 07, 2017, 05:40:30 PM »
Is there a strong blue ignition spark?  Inspect all of the fuel hoses for kinks or collapsing then check fuel pump draw, pressure and volume.  Any possibility that someone installed a redundant fuel filter?  If so, replace it.  Fuel filters have a marked direction of flow - make sure it is (they are) installed correctly.  Verify the carburetor float level is correctly adjusted.  Is the 'gurgle' originating from the exhaust?  Check for excessive exhaust backpressure.  Temporarily disconnect the exhaust close to the engine if you need to - but don't do this at night in a "quiet" neighborhood - lol.  Does the transmission downshift with rapid throttle opening below about 40 MPH?  Recheck the detent cable adjustment.  Is the transmission full of fluid?  Verify that the transmission vacuum modulator valve is receiving full manifold vacuum and that there is no evidence of ATF dripping from the modulator valve nipple or its vacuum hose when the hose is temporarily removed from the valve for inspection.

How did I not see your post and then ask the same question? durdeedurr
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Online bd

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Re: Engine Struggle
« Reply #24 on: August 07, 2017, 05:54:17 PM »
Trust me.  It gets worse as you get older!

Besides, great minds think alike!   8)
« Last Edit: August 07, 2017, 05:57:37 PM by bd »
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
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Online VileZambonie

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Re: Engine Struggle
« Reply #25 on: August 07, 2017, 06:09:10 PM »
lol
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Johnbravado

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Re: Engine Struggle
« Reply #26 on: August 07, 2017, 07:42:10 PM »
So I am trying not to go through the transmission problems and hoping that resetting the timing will fix it. The timing was off a lot at 4*. It always sounds good though the first run. It is that 30 minutes drive to work or home that exposes all the ailments. Today I felt the messed up action. But when I got home. I rotated carb and the engine reved up to 1100 rpm from it's previous set idle speed of 650. I had to bring it back down to 650 and finally got it 10* @ 65rpm. Maybe a little more than 10*. I just want to stick with spec recommended right now. I am hoping this is it. If not I am going through bd's post item by item

This was a giant learning experience for me. Vacuum leaks, tune up stuffs. First time timing and carb setting. I think I still need to readjust the carb since I adjusted the timing. But it was a little rainy and I had stolen someone's covered parking to do the timing real quick.

Offline Outacontrol

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Re: Engine Struggle
« Reply #27 on: August 08, 2017, 02:29:50 PM »
I'm having similar issues and then I started tracking down all the vacuum leaks, and then realized that the accelerator pump discharge nozzles were plugged from the ethanol residue in the garbage gas.  I ran a small piece of wire in there and cleaned them out, big difference.


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Offline roundhouse

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Re: Engine Struggle
« Reply #28 on: August 10, 2017, 09:59:55 PM »
You put a pressure gauge the fuel line at the carb yet ?


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Offline Johnbravado

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Re: Engine Struggle
« Reply #29 on: August 19, 2017, 11:44:55 AM »
no but i just bought a new fuel pump since it is like 20 bucks and 2 bolts. i am replacing that tomorrow. I get that feeling like my gas is flooding then starving than flooding and starving while driving an dnot moving the gas pedal. it is either pump or i am rebuilding carb and something is blocked