Carb troubles..... Go figure (1 Viewer)

[Toast]

Hey so I'm sure there is a thousand threads out there like this one but I was hoping for some current feedback. My EFI build is underway but I need my truck to hang in there for a while. My truck has been hesitating and bogging down with intermittent loss of power. It acts like its starving for air and possibly fuel. Did some reading. What does a power valve do? Also what does an aux accelerate pump do? Any and all help is much appreciated. Thanks

 

[Mudder]

Did you check the filter by the gas tank?

 

[Toast]

Yep, even changed it for good measure. I keep up on my filters. Someone told me it could be my fuel pump. Thoughts?

 

[Mudder]

It could be. Pop the valve cover off and check the arm and the the lobe

 

[Toast]

Not my fuel pump. I had a new oem one laying around so I slapped it in. It seemed to help a bit but no cigar. Still hesitates from stops. I'm thinking it's something with in the carb but I don't think a rebuild is going to help

 

[BioTex]

Sure sounds like fuel starvation. Float level possiby too low?
Could you have purchased some bad gas?

Try not to assume anything when troubleshooting. Put a fuel pressure gauge inline and verify you have sufficient pressure. Only way to be 100% sure IMO. Then you can start narrowing down the culprit.

Double check for vacuum leaks and the usual EGR/PCV issues.

You asked about a power valve. I do remember on the old Holly carbs with a power valve, if you ever backfired though the carb it would take out the power valve. Perhaps that is what happened? Honestly, I didn't know these carbs had power valves in them. I'm new to them, but have been around older carbs for quite some time. Just not the Japanese versions...

 

[Toast]

Pulled the carb off today. Gonna go through it tonight. I'll see what I find

 

[Toast]

Found nothing to be bad. Cleaned it really well, blew it out. Cross your fingers. I'm going to pull my EGR off for good measure, and check it

 

[Toast]

Accelerator pump is bad. Tanked my cat in the process. Those out there with carbs be warned: if your carb starts acting up, fix it and don't drive it. Bad accel pump was flooding my carb causing it to load up and backfire which blew my cat to shreds. The end

 

[Toast]

Ordered a new carb from the carb exchange in so cal. It's amazing. The carb looks brand new! Slapped it on and it fired up. Now I have to do my entire exhaust system. Is it ok to drive a short distance with no exhaust?

 

[BioTex]

As long as you have some sort of an exhaust manifold on it will not burn the valves. A header or cast iron manifold will work.

 

[Phares]

Just crawled under my truck today...my muffler looks like a crushed beer can....New exhaust coming up. I did the new carb thing last year

 

[Toast]

So the final verdict is I upgraded my exhaust to 2 1/4 from the cat back with a test pipe for now. Wayyyy more power. Crazy enough my truck started doing the exact sane thing again. Would stumble and fall on its face under acceleration. So my coil ended being bad. It was a crane cams ignition system. Swapped back in my OE coil and igniter and my truck runs perfect now! Crazy

 

[welder7018]

efi build ? or carb? screw efi put on weber best money ever spent desmog and your done

 

[Mudder]

EFI>then carbs. How's the swap coming along toast?

 

[Toast]

Lol well.... Having found out I've got kids on the way kinda slowed things down. But it would be coming along if this flakey machinist would give me my freakin block back! It's been on standby for a while and I really want to jump back into it before I have no more $$$ left!

 

[Toast]

efi build ? or carb? screw efi put on weber best money ever spent desmog and your done

De-smog? Yea right I wish! Here in the great state of California our mass liberal crowd doest want the yellow bellied spotted gecko to have trouble breathing...

And although there is simplicity in a computer less carbed vehicle, I would like; better fuel economy, more power, being able to climb a particular hill that my EFI buddies can climb but I can't. Tired of dealing with finicky carbs that all seem to have a "personality".

 

[Mudder]

Congratulations on the kid on the way Toast! I'm glad to hear that it's kinda coming along besides the block factor.

 

[Toast]

Kids. 2. And I'm not super excited about it but at least I have someone to give my truck to when I'm old