HHHEEEEELLLLLLLPPPPPPP!!!!!! Update- problem unsolved again.

[fast_n_low86]

Ok, so I'm having a major issue right now and I'm out of ideas on how to fix this. Truck has ran great with my new (to me) motor transmission until I had to swap my mild performance to full out performance distributor. I adjusted the carb and timing once I made the swap, it ran good for a few days and now I've been fighting with it for almost 2 weeks. Idles good, got my fuel/air mixture good, drives good through the low intown speeds. Once I go to the highways speeds (70km/h +) the mixture goes super lean and pretty much stalls my truck out. Been trying to solve that and everything I have done has made little to no improvement. I've checked for vacuum leaks, leaky carb, changed out my electric fuel pump to a more carb friendly one, I've cleaned my carb and made adjustments to all metering and Jetts. Adjusted my accelerator pump. I've done pretty much everything I can think of and what I've been told in my repair Manuel's and everything. Anyone have any clue or ideas on where to look?



UPDATE- Resolved the problem..
BIG NOTE- always make sure you anything that needs vacuum to work to the correct vacuum line..
RESULTS- Had my fuel pressure regulator hooked up to the wrong vacuum line off my carburetor hence when hitting highway speeds I'd lose fuel in my mixture. No vacuum = no fuel pressure = no vroom vroom

 

[75gmck25]

How do you know the mixture goes super lean at highway cruise? Could it just be starved for fuel? Did you change anything on the fuel system when you changed the distributor?

Is there a brand on your “full performance distributor”? HEI module, advance mechanism and other parts could be bad, even if it’s new.

 

[fast_n_low86]

I installed a wideband fuel/air mixture guage in my truck a while ago so I could monitor it. It runs great until I hit highway speeds and then she spikes right out of range to the point my truck stalls out or it will flutter in-between to lean and just able to run, then I lose all speed and it will go back to normal operation when driving at town speeds. >60km/h.

Distributor is F.A.S.T. and it's running good. It's a fully adjustable advance setup. So I've though maybe it's advancing to far forward at those speeds.

Just though of it now that maybe it has something to do with my fuel pressure regulator (possibly my return line or its clogged)

 

[hogdaddy]

With thar fuel line at the carb, you have basically a rubber line making a hard 90* turn. I would correct that first.

 

[StickyLifter]

I probably won't be any help to you, but it's interesting that you're having air/fuel mixture issues after changing out your distributor. Did you remove the carb or fuel lines while changing the distributor? How does your air/fuel mixture look when riving your engine in park/neutral?

My initial thought when I read the first couple sentences was a vacuum leak, but you said you checked that.

Please update when you find the issue. I'm curious...

 

[fast_n_low86]

Revs good. Hold the rpms at 2500+, still good. Only thing is I changed my airfilter to an open top filter. Had to change my distributor because the old ones shaft was bent (inset dick joke here). So it would skip out of time while driving. Should've remembered that's why I changed it out on my other engine before it blew up..

 

[hogdaddy]

Those open top filters in your pic suck in my experiences!

 

[nvrenuf]

I agree it sounds like it’s starving.

Be sure to test drive it with either no air cleaner or your old proven unit to be sure there’s nothing weird there (like physical contact, etc).

 

[fast_n_low86]

That's the old one I took off. I will take a picture here when I finally go out and start wrenching on er some more. It's one of those triangular all open filters.

 

[fast_n_low86]

I have switched back and forth between the 2 filters and besides the lack of power with the round one due to starving for air there is no change to the problem.

 

[fast_n_low86]

I'll snap a few pictures here in an hour or so when I go out to start working on er again. Everything ran good and strong and fast until I had to change out my distributor and adjust my timing and what not.

 

[rusted nuts]

Ok, so I'm having a major issue right now and I'm out of ideas on how to fix this. Truck has ran great with my new (to me) motor transmission until I had to swap my mild performance to full out performance distributor. I adjusted the carb and timing once I made the swap, it ran good for a few days and now I've been fighting with it for almost 2 weeks. Idles good, got my fuel/air mixture good, drives good through the low intown speeds. Once I go to the highways speeds (70km/h +) the mixture goes super lean and pretty much stalls my truck out. Been trying to solve that and everything I have done has made little to no improvement. I've checked for vacuum leaks, leaky carb, changed out my electric fuel pump to a more carb friendly one, I've cleaned my carb and made adjustments to all metering and Jetts. Adjusted my accelerator pump. I've done pretty much everything I can think of and what I've been told in my repair Manuel's and everything. Anyone have any clue or ideas on where to look?

Bad fuel filter and weak fuel pump can cause this also.

 

[fast_n_low86]

Well after all the heartache and ******** for 2 weeks. I finally realized that my fuel pressure regulator wasn't working right and I solved the issue. It was not hooked up to the correct vacuum line. So when I finally would hit highway speed my vacuum would drop right off and thus closing the regulator and choking my truck to death

 

[fast_n_low86]

Those open top filters in your pic suck in my experiences!

 

[fast_n_low86]

The problem has come back and I'm not sure what to go to now.