yeah you know you could be on to something about the pump. Cuz when I test drove it a while back it wouldnt like getting over 2krpm either cuz it seemed to run better when bogging in to high a gear. Also didnt like going up slight inclines either, and would backfire sometimes when I was trying to get up the hill.

But I dont recall black smoke when I got it up to 2k rpm but I'll do it again today and check for that and have my dad watch the vacuum gauge as well.

jetting shouldn't be blocked I have took that carb apart 3 times now and blew it out all orfices with compressed air.

float level was set right at the sight hole when removed and engine idling. Now if the pump is getting funny when its under pressure to deliver to the engine it might drop idk I cant be everywhere at once checking everything Haha. This is why I have the mechanical pump so maybe I'll just start rerouting my fuel lines for that setup and then get back to the running issues.

but the power valve you mentioned, how do you tell if its failed? Mine seems in tact and the spring thing on it is good and moving. How do you get a definitive test for a failure there?

 

Ok I replace the mechanical fuel pump on the engine and it seemed to have improved a bit and is not dying now but I figured out the egr valve is causing a vacuum leak now. That's what was causing the issues once engine was warm, and I got up to 1500-2000rpm the ported vacuum was pulling and the egr valve was leaking threw diaphragm. Go figure all the vacuum diaphragm components are going bad as I'm trying to bring it back to life. Maybe once I get this new component it will run better for driving. Cuz it seemed to run decently with new fuel pump and vacuum hose to egr plugged. But when I drove it like that once I started to go up a hill and kind of into the throttle I was getting a bit of stumbling. But for the most part getting into throttle was much more responsive once i plugged the egr from leaking. Before it was very hesitant and had to feather throttle as I was taking off. Also the accelerator pump cam was in the #1 screw hole and i changed that to #2 screw hole and it took away the minor backfire I was having so I think I'm getting closer to just carb adjustments. But not 100% sure, it's hard bringing something back to life that has been rigged by who knows how many previous owners that just used and abused the old rig. And to top it off I'm no master mechanic, just a wanna be for now, but I'll keep pecking away at what I can and learn as I go.

 

Good to see progress....."..Glad I could help....."

 

Ok so I'm completely stumped now... I have replaced so many things, it's gotten the complete tune up. And it's still sputtering at idle once it warms up to operating temp. I just finished up replacing the timing chain and gears and all that jazz. The chain was pretty loose. So that actually did improve the way it was running and revving a bit until it began to sputter at operating temp. Had to readjust timing once I got it to start up after the replacement, it was retarded to like 3° or 4° btdc. And I did have it set at like 10°-12° btdc, so that new chain and gears changed something up, "for the good" I'm hoping. Anyway could I be having problems with emissions stuff since some components arnt even hooked up like the vac canister and I believe there should be lines running to the fuel tank vent... could these issues be causing my problems? Should I disconnect something since that isnt there? Like I said previously 1st air pump (pass) hooked up to air by-pass valve then to exhaust manifolds[ABPV vacuum port hooked up to manifold vacuum]. 2nd air pump hooks to the top of breather above air filter. Egr valve is new and hooked up like my diagram shows. So I'm wondering if my issues are with that canister and the fuel tank vent lines.... idk, please throw me some ideas. Only other thing major I can do is rebuild the whole engine and I dont believ that's gonna fix my issue Haha. Its gotta be something simple that I'm over looking. But for the most part my backfires are gone and it starts and runs good before it reaches operating temp then the sputters come in.

 

Any vacuum connection should be properly connected or at least run down so you don't have a vacuum leak.

The evap stuff is harmless but needs to be connected or you could have a vacuum leak. Check the condition of the hoses involved as well, including the fuel tank filler and cap.

As for your timing, you can't be too far off, but double check with a timing light.

 

ok so I checked timing and adjusted it to 6°-8° once I realized it was retarded to 3°-4°, like I said, before the replacement of chain and gears it was set at 10°-12°BTDC. so as of right now my timing should be spot on according to my valve cover spec sheet sticker.(6°btdc for the 6.1l 370engine @600rpm idle)
I have also replaced my vac lines so they are new rubber.Also while doing all my investigations, idling the engine I have had the vac gauge hooked up the whole time and while its idleing its steady, now when I blip throttle it goes down then spikes up then starts to even back out and some sputtering happens then it idles fine. Until operating temp is reached then idling begins to sputter and eventually dies out.

Now you said something about fuel tank filler and cap??? I have the passenger step fuel tank so the filler is the metal pipe fitting with screw on cap it has a seal inside of cap to seal onto threads once tightened.

 

WAG. Check for a vacuum leak around the intake manifold. My folks had a 460 that defied all attempts to get it to run smooth. Then they hit the edges of the intake and voila, leak.

I think this was particular to the car 460 from that '77 or '78 model year, and not a problem on all of them. But it will cost you about 10 cents to check.....

 

yeah I've been studying my manual like homework. And I was planning on running threw the vacuum gauge troubleshooting tests for all the different components and be sure everything checks out alright. Also I did see something about somebody saying to use a handheld propane torch and release gas w/o spark and outline the edges of the intake manifold while it's running and if it revs likes it's getting more fuel then its sucking propane into the intake seal. I could try that too I guess. I would think if its leaking it would all the time but i guess there could be some gunk plugging it until it warms it up and loosens the gunk up and leaks. Maybe?.?.? Can I use map gas instead of propane? Not sure if I have any propane cans for that torch I have.

 

You can used WD40 or brake cleaner. Any liquid is going to stop the vacuum leak for a second, any flammable liquid will raise the idle. The propane or mapp will raise the idle but be a little trickier to work with methinks. Be careful!

 

Here's a better picture of the controls:



Not sure if you've gone through the carb:

 

well I'm still unsure weather it's a vac leak, bcuz it would have to only leak once it warms up to operating temp. And that sounds crazy that it would be so spot-on on leaking at the same exact time once warmed up. That's why I'm thinking it may be a vacuum routing issue because I dont have the original carb for my engine, and they are obsolete. And for that matter their are probly other original emission components that I dont have in my vac routing when i compare my setup to my original vac line diagram in my book so this is where I get lost.... lol. What all is NEEDED "emissions-wise" for my 1985 6.1l 370 engine to operate correctly with my aftermarket 2barrel holley 7448 carburetor?

Part of me is thinking it could have something to do with the "thermal vacuum check valve" that screws into the water jacket on intake it's the 2 port valve. My vac diagram shows two of these in the system and one of them is a 3 port. I'm gonna post a picture of my books vac diagram....

 

This is a drawing of how my current setup is... i did my best lol

 

We had a F-600 of about that vintage in out volunteer fire department that when brand new would float the valves and stall if it was over-rev’d even a little before shifting. Could be you have weak valve springs?

 

would weak valve springs cause the engine to stall out when idling fine until operating temp is reached? My engine seems to rev up fine and idle fine when I first start it but once my temp gauge reaches the operating temp that's when my vacuum gauge starts to sputter around a bit and then stalls out. It will start back up fine after a bit and then does same thing. I'm gonna unhook and plug all my vacuum operated components individually today and try to narrow it down that way maybe... I'm going crazy trying to figure this last step out, I've gotten so far with it cuz it actually starts and runs and revs up good now without issues until operating temp is reached, then it sputters out.

 

Also I havnt had a backfire in a while so that issue has been resolved with one of the many new components I replaced/adjustments made.