Projects Cutting my Hotrod Teeth (57 Chevy Budget build/revival)

Oh, and thanks to all the help and knowledge you guys have shared with me throughout the years, I’m getting a lot better at problem solving car issues. I just got done putting the motor back in my OT project, but it wasn’t firing and then would backfire through the carb and sometimes shoot a little fireball out the exhaust while cranking. Well, thanks to that knowledge I was able to figure out the plug wires were in the wrong order, so I switched them and it fired right up! I had ZERO help with it, so it feels great knowing I can get a non running engine running again on my own.

 

New exhaust sounds real nice. It has to feel good to actually drive the car, even if it does have some bugs to work out yet.

 

Absolutely! Been a long time coming!

 

So I but a new accelerator pump in the Edelbrock, but it looks like my fuel delivery problems are twofold…

Now, I’m getting good squirts of gas with the accelerator pump, but the motor just dies and then the float bowls are empty, and it will only run off the gas in the bowls. So, it looks like the fuel pump I installed only a couple months ago, and which has less than 30 miles total on it, has most likely gone bad already. DANG IT!

Here’s another symptom I noticed that occasionally happens; At idle, the RPMs will raise and lower. Sounds to me like it might be starving for fuel? This would also make sense why while driving, it bogs when I lay into it. It’s just not getting enough fuel. Looks like @Johnny Gee was right!

Now, before I go taking the fuel pump off, I’m also going to try running it from an electric pump out of a jerry can again. If it stays running like that, I’ll pull the fuel pump off and either throw the other “good” one I have that fits on, or install that Carter electric unit I bought last time I had fuel issues.

I’m so sick of new parts being junk. It makes used older parts the much more attractive option.

 

New fuel pumps being junk right out of the box (or failing near immediately) is an unfortunately common issue in the last few years, I've had it happen as well. Inconsistent fuel pressure is also an issue, I've had to use pressure regulators in several cars that shouldn't really need one, although that's caused by too much fuel pressure and your issue sounds like not enough.

Are you aware of the little screen pre-filters on most of those Edelbrocks that go in where the fuel line connects? I know when I first got my '57 going I plugged those up a couple times with stuff that got past the inline fuel filter somehow.

 

Hmm, I did check that recently, but not since the break down yesterday. I’ll have a look

 

So this morning i decided to try a fuel pressure test since I have a port for it on my fuel line up by the carb. The results were not what I was expecting. I got a very consistent 6 psi while cranking, and then, get this… the car started right up like nothing ever happened

The idle is pretty rough though, and I’m not sure what to try first. Obviously I will check the filter screen in the carb, but in the meantime here are a couple clips. In the first one, you can hear the RPMs raise and lower repeatedly. Looks like between about 700 and 1200 RPM. I thought maybe it was running lean and just wasn’t getting enough fuel so I loosened the idle mixture screws, which then caused the idle to be very rough, with lots of sputtering and pops out the exhaust…

 

Just did a couple more tests. Fuel pressure stays consistent right between 4 and 5 psi while idling, and even if I rev it, so maybe the fuel pump is fine after all?

Obviously since RPMs are fluctuating, I had to check timing and it’s fluctuating at idle too.

 

I also cleaned and blew out the little screen @Squablow mentioned. It didn’t look dirty, and unfortunately the motor is still running the same.

 

Pitiful vacuum, and of course it’s also fluctuating between 6 and 1 inches of mercury… yikes!

 

Is it possible I have a vacuum leak between the intake and heads? Not sure if that’s even possible with the sbc design. I’m grasping at straws here because nothing seems to correct it, and none of the things I’ve checked have led to any answers. Yes obviously the RPM/Vacuum/timing is fluctuating, but why?

Oh, I also put my hand over the carb throat while running and the idle picks up (but still runs uneven) which would lend credence to it running lean, but any engine would speed up if the mixture was richened, right?

 

Aaaaand, the motor died and i’m not getting any squirts of fuel if I pull the throttle back

Maybe a float issue? Floats not keeping enough fuel in the bowls so then they run dry?

 

Here is a WAG and I do not remember. Is your fuel tank vented? If you don.t know try running with the gas cap loose.

 

^^^^ To add, you should be using a vented cap. Not a sealed one.

 

I’ll definitely try that next. I was thinking about cranking it or running it with float bowl gas until it filled up a cup or so of fuel, and timing it while it filled, but that’s a good rule of thumb.

 

Hmm, the tank is vented yes, though I’m not sure if my cap is. Worth a shot trying to run it with the cap off!

 

I also took the top off the carb again and did find some chunks of rust near the little screens at the needles and seats where fuel flows in. I missed the one on the driver side last time, and that bank of cylinders seems to be running rougher, so hopefully that’ll help. It certainly can’t hurt.

Also confirmed the floats are at the Edelbrock specified level, and cleaned out the needles/seats just to be sure, but all looked very clean alreay.

 

Okay, I cranked it for 15 seconds, but the battery is a little tired from yesterday so I stopped there. I’d say this is 2/3 of a pint of gas pumped in 15 seconds. My quick in-my-head figure is about 20 GPH based on a gallon taking almost 3 minutes, if I were able to keep cranking, and 20 gallons times 3 minutes each, you’re at an hour for 20 gallons.

 

From my limited understanding of flow rate, 20GPH is extremely low, no?

 

Also, wouldn’t the flow rate be much higher while the engine is running rather than cranking? The pump I have is rated for 80GPH, though we all know how accurate the specs on these cheapo junk new pumps are…

https://www.summitracing.com/parts/tsn-jm1003c

 

Keep at it.

When i was starting to figure stuff out on my own, sometimes I had to redo things 3 or 4 times before it worked right.

I love old cars.

Say it loud and often.

 

Do keep in mind, you only have to keep the float bowls filled. When idling or cruising at light throttle, it doesn't take much to keep gas in the bowl. Free flow gph will change with pressure increase. Yeah, notice how there isn't standardization for the flow ratings.

 

Alright, well I think the fuel starvation issue is fixed, but unfortunately I won’t really know unless I drive out of the neighborhood and get out on the highway again. The car isn’t doing that erratic idle since I put the carb and fuel lines back on, but with how good it ran the morning I picked it up from the shop, I’m just not confident in it yet. I ended up just tightening the gas cap enough to stay on the filler neck. If it does fall off, the fuel door should catch it.

I did give it a few revs to about 3k for a few seconds, and then all the way up to 5k with a couple quick blips to see if the bowls would empty, but the car did come back down and idle. Hopefully it will at least be tunable now!

 

Oh, and soot spots on my driveway probably means running rich, huh?

 

Zero real road time and lots of playing with it in the driveway can build up a lot of carbon etc in the pipes. Your rev test blew it out. How do the spark plugs look?

 

I’ll check them once the engine is cooled down. I just took the car out on the highway again where I could really mash the gas, and it’s definitely running better though not quite dialed in yet. I got a couple of backfires and it did bog a little bit as I was just about home, but thankfully this time I didn’t end up stranded.

 

Popping out the exhaust when I let off the gas, and the occasional carb pop while laying into it points to a richness problem right? I’ve always ***umed anything with the exhaust popping means late spark or too much (unburnt) fuel

 

Plugs are pretty black, but I think I’m going to clean them and put them back in and check after another drive or 2. I’ve been playing with the carb enough that there’s no telling if the soot is recent for from before I adjusted it to how it is now.

 

One change at a time. Verify timing & advance still where they should be.