HELP!!!!

NastyRay · May 10, 2022

so I have a big block 454 stock with a Holley mid rise I guess you call it intake and an Edlebrock 1407 performer carb and I use a spacer plate. I am having the worst time. I can not get my truck to run under 3000 rpm. it’s a Manuel trans btw. Idk what else I can do I feel like I’ve tried everything. Since my first startup it has not ran right I fought it the whole time I can’t even get a timing light on the damn thing to even see if I’m close. I need some serious advice. Thanks in advance guys

85K304SPD · May 10, 2022

What do you mean when you say you cant get a timing light on it? Also what do you mean that y0ou cant get it to run under 3000 rpm? It wont idle? How worn is the 454? Fresh or high miles?

fast 99 · May 10, 2022

When did this start, was any work done before the problem cropped up?
Not running below 3k, vacuum leak, misfire, one side of carb no fuel, stuck valve especially intake. What is the vacuum reading and is it steady? Compression test?

Bextreme04 · May 10, 2022

I would be looking for a massive vacuum leak. Do you mean you can't get the RPM to go below 3k RPM, or that it wants to die if you get it lower than that?

Pics of the setup would also be good

Catbox · May 10, 2022

Mine would not *want* to run below 3k when I had knocked off a couple of vacuum lines and forgotten to hook them back up.

Look for the vacuum leaks...

Bextreme04 · May 10, 2022

A big oops that I've seen is when people have an aftermarket carb/spacer/intake, they don't check for clearances and they tighten the carb down with it catching on something. Depending on what is caught, you can end up with a carb gasket not sealing, throttle plate stuck open partially, or damaged linkages. Check to make sure the carb and spacer are tight and flush and that nothing is touching or binding. Make sure the throttle can move freely and snaps back to fully shut. Make sure the high idle screw isn't too tight and causing it to rev high(that's the one on the passenger side facing down at the intake).

SirRobyn0 · May 10, 2022

Bextreme04 said:
A big oops that I've seen is when people have an aftermarket carb/spacer/intake, they don't check for clearances and they tighten the carb down with it catching on something. Depending on what is caught, you can end up with a carb gasket not sealing, throttle plate stuck open partially, or damaged linkages. Check to make sure the carb and spacer are tight and flush and that nothing is touching or binding. Make sure the throttle can move freely and snaps back to fully shut. Make sure the high idle screw isn't too tight and causing it to rev high(that's the one on the passenger side facing down at the intake).

I've seen guys brake ears off carbs because they caught it on something and kept cranking down or were using power tools.

I agree look for massive vacuum leak.

NastyRay · May 10, 2022

85K304SPD said:
What do you mean when you say you cant get a timing light on it? Also what do you mean that y0ou cant get it to run under 3000 rpm? It wont idle? How worn is the 454? Fresh or high miles?

It is brand new I can’t get it to run at less than 3000rpm and at the high rpm a timing light is useless

NastyRay · May 10, 2022

Bextreme04 said:
A big oops that I've seen is when people have an aftermarket carb/spacer/intake, they don't check for clearances and they tighten the carb down with it catching on something. Depending on what is caught, you can end up with a carb gasket not sealing, throttle plate stuck open partially, or damaged linkages. Check to make sure the carb and spacer are tight and flush and that nothing is touching or binding. Make sure the throttle can move freely and snaps back to fully shut. Make sure the high idle screw isn't too tight and causing it to rev high(that's the one on the passenger side facing down at the intake).

I did check to make sure nothing was binding or hitting. I couldn’t get it to run period before I put the spacer. I put the spacer and now I can get it to run only at 3000 rpm. Before the spacer I could only get it to run is with the choke on. Also the response to the throttle is weird when you hit the gas it stays at a rev and doesn’t come back down like it should it hits snappy but stays like your on the gas for a few seconds then drops back down

Bextreme04 · May 10, 2022

NastyRay said:
I did check to make sure nothing was binding or hitting. I couldn’t get it to run period before I put the spacer. I put the spacer and now I can get it to run only at 3000 rpm. Before the spacer I could only get it to run is with the choke on. Also the response to the throttle is weird when you hit the gas it stays at a rev and doesn’t come back down like it should it hits snappy but stays like your on the gas for a few seconds then drops back down

Sounds exactly like BIG vacuum leaks. start it up and start spraying everything with carb cleaner until you hear a change in RPM. I would look closely for any open port, cracked vacuum lines, or large gap near a mating surface.

Post some pics of the engine and engine bay

Grit dog · May 10, 2022

I’m grabbing at straws a bit here and having a detailed account of what the truck acted like and what you changed and how that changed how it ran would be helpful.
Like it won’t stay running unless you hold the throttle open at 3000rpms or it lights right off and runs at 3000rpms?
Former suggests big vacuum leak. Latter suggests problem with new carb, IMO.
Any other work, timing, distributor etc done?
I see a pic in your avatar like it used to run fine in the past? Trace back what happened and what you did from there til now?

NastyRay · May 10, 2022

fast 99 said:
When did this start, was any work done before the problem cropped up?
Not running below 3k, vacuum leak, misfire, one side of carb no fuel, stuck valve especially intake. What is the vacuum reading and is it steady? Compression test?

It’s brand new build first fire and can’t get it to run right. Brand new crate motor. Compression is good on all cylinders I don’t have a vacuum gauge Spose I need one huh

NastyRay · May 10, 2022

Grit dog said:
I’m grabbing at straws a bit here and having a detailed account of what the truck acted like and what you changed and how that changed how it ran would be helpful.
Like it won’t stay running unless you hold the throttle open at 3000rpms or it lights right off and runs at 3000rpms?
Former suggests big vacuum leak. Latter suggests problem with new carb, IMO.
Any other work, timing, distributor etc done?
I see a pic in your avatar like it used to run fine in the past? Trace back what happened and what you did from there til now?

Problem is I put a brand new crate 454 in it and dolled it up. She isn’t happy about it

NastyRay · May 10, 2022

This is the motor

NastyRay · May 10, 2022

Ignore msd I decided to not use it

HELP!!!!

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