Fuel System doesn't react to mani pill changes

Fuel System doesn't react to main pill changes

I am looking for ideas.
I have a proven blown alky fuel system that suddenly, without any known changes, does not get more fuel into the engine when the main pill is made smaller.
We have changed the hose that supplies the pump, the pump to MV, taken the distribution blocks apart, rechecked the openign crack psi of the high speed and the filters have been and are still clean (there is one right before each dist. block).
I'm on to my 3rd pump and I replaced the 3 way shutoff.
The tank vent seems fine.
I now have the blower, fuel system and ignition on a different engine and its the same scenario.

What other things can I look at?

 

I had this happen to me once. I had the check valve in return line in backwards.

 

If it's a Enderle K Valve, make sure you don't have two jets stacked in the port , two will fit in there ------------

 

Thanks for the suggestions, I have checked the poppets and they are in correctly, also with doubling up the main pill. Both of these would richen the engine and i have the opposite.

Its too lean and putting a smaller main pill in doesn't richen it, at least by as much as it used to.

The first 7 passes this year we were spot on with this tuneup.

 

FYI, this same thing can happen in a square barrel valve

 

99% of FI tuning issues are electrical.

Dave Koehler
http://www.koehlerinjection.com

 

Butch, try your PM again, I cleaned it out some

 

Do you have any ideas how a Mallory Supermag IV and a 2900A coil can make the engine seemingly leaner than it had been?

Please, I'm open for any ideas, as wild and crazy as you might think they are...

 

valve

newby here, but ive seen a couple of k valves with the spool in upside down. im sure you know about the notch in the new ones, but the old spools didnt have a mark what was up or down. they will run either way, but one way with the v in front is much better. maybe?

 

For what its worth,take a can of starting fluid while engine is running,spray it around blower top and bottom anywhere there is a parting of components.If the RPM goes up you have a leak and are sucking air.DAVE

 

Maybe a leak between the blower and manifold. Is the spool in right, the engraved line should be between 12 and 1 oclock. Try richening the barrel a bit and see if it runs better.

 

Are you sure that your pump is good? We had one that was going away once and it acted a lot like what you have described. Changed pumps and all was good.

 

Pretty sure its not as I flow tested the 1st pump and it was going away so I changed it and have since changed it again.

To all who have suggested air leaks it idles fine and any blower to intake leaks I've ever had didn't do this. I am now running a different long block (intake to pan) with the same results.

To Mike: As far as how do I know, the short answer is plug readings. I've rechecked the timing several times on both long blocks.

It was suggested to check for suction side air leaks and I did have a very tore up -12 o-ring right on the pump inlet fitting.

Have you ever heard or had a tore up o-ring sucking air?

 

I had this same condition on a 110 pump last year. Engine would not respond to pill changes. Found pump inlet side o-ring torn. As preventative maintenance, sent pump to Enderle to have flowed. Found pump had gone away as well.

 

I know on hydraulic gear pumps that I work with (at my real job), if you suck air it can ruin the pump, I wonder if this true on Enderle pumps?

 

o ring

[.

It was suggested to check for suction side air leaks and I did have a very tore up -12 o-ring right on the pump inlet fitting.

Have you ever heard or had a tore up o-ring sucking air?[/QUOTE]

Any time you have even a small ( like razor blade cut) in an O ring it WILL leak under vacuum ! But not necescerally will it leak under pressure. One of first things on your maintenance or trouble shoting list.

 

Flowed pump

When you said you flowed the pump did you actually have it flowed on a flow bench? Flowed by somebody reputable? A friend of mine just bought a pump that had a tag attached to it that said it flowed 16.2 gallons. The car ran like crap so he sent it to a reputable fuel system guy and it actually flowed 11.2. Apparently anybody can fill out a tag and attach it to a pump. Dave Germain

 

Yes, flowed on a flowbench and its my bench and I did it

Hindsight the problem was intermitent in the beginning, then became a probelm every run.

 

If you have your own flow bench, why can't you flow the complete system to determine if the fuel system EVEN is the problem--------------???????

If you have a question about sucking air might damage the pump why not flow it and rule it out ???????
I think you are focusing on what you think is the problem, the fuel system, when as Dave K. posted--- it could be in another spot .

If I had a flow bench my pump would probably be worn out! LOL