Moose Trouble

[Frank]

For those of you who went to Moose. The trouble I had at the end is gone . Washed her and took her off the trailer and BOOM ! She was good to go. Now Im not sure where to start. For those who werent there. Mona ran fine all day and after airing up we headed out , When we hit the black top and started to increase speed , Mona would lay down like outta fuel . We stopped and I had plenty of fuel. It starts right up , idles fine, no throttle response . It starts to accelerate and goes flat like its out of gas. The more you push the skinny peddle , the more she dies. This is my first issue with all that EFI BS ! Found the book for the Holley Projection , will give it a whack today and see what I can find. Any ideas ????? FjR68

[mrfreakinwhite]

fuel filter flows enough to idle, can't keep up with demand?
When you let off the gas, does it feel like it wants to surge forward?

[Frank]

Not really Mike. It ran impeccable all day. In low range you arent pushin the pedal that much. On the road if I eased out of the throttle it would come back. I also weaved the Jeep like a race car would do to try to pick up fuel. That wasnt the issue. I had about 5 " of fuel so I knew that wasnt it. The low pressure filter looks dirty , (the tank is brand new clean) I will change both filters tomorrow and check the fuel psi at the throttle body and the TPS volt reading as that was a critical measurement when I set it up. Thanks FjR68

[Frank]

This is an older Holley analog stand alone TBI unit. On the comp you have 5 dashpots you adjust for idle,accelerator pump,midrange,power ,and cold start which never worked. At F&F I usually have to adjust the idle and mid I assume because of elevation. There are no O2s in the system. This feels like the accelerator pump isnt working. If you ease into the gas it will raise the rpm , if your to quick with the peddle it will stumble till you back off off the throttle. One filter is clear the other is metal so you cant see the condition. I will be trying to check the TPS setting as that was critical when I changed it, the fuel pump psi, and Im gonna call Holley Tech and maybe get this straightened out. Thanks FjR68

[mrfreakinwhite]

It still sounds just like a fuel filter is clogging during demand, the junk settles during low demand.
But who knows, internet diagnosis isn't what it was in the old days.

[Frank]

Ran through the whole set up trouble shooting thing . Noticed on prime ( not started) fuel psi is at the selected 12psi. Then it drops off to about 6 psi. While running it is at 12 and when the rpms are raised to about 3k it drops to 6/7 psi. The pump is about 1.5 yrs. old. External with two filters,one before and one after. Im going to pick one up sat. morning. Didnt have one in stock. Holley tech said also thinks pump is giving up. Whatcha think ???? FjR68

[mrfreakinwhite]

I still think it is external fuel filter.
Are you testing psi after that filter?

This is a pretty low pressure system for fuel injection.

I hope you don't have to drop the tank, I hope it is easy.

[Frank]

Mike : Its an aluminum tank with an external pump. Ive been noticing that it takes longer to prime the system. A couple weeks ago I had to make major changes to the computer dash pots. I tested it at the TBI and when I saw it drop after it primed , I tested it after the pump . Same thing, prime to 12 and pump shuts off and it drops to 6 or 7 lbs. The pump is bleeding off I guess. The clear filter (low psi) before the pump stays full when its running, the high psi filter is metal and Im going to change them both with the new pump. This pump is supposed to supply a engine with up to 275 hp. They have another pump that can handle to 400 hp. Which one do you think I should use. My engine is about 260 hp with 360 ft.lbs . The computer has two maps, a small block to 300 hp and a bb to 400 hp. I use the sb map and the recommended tbi psi is 12-15 lbs. It runs clean at 12 and hasnt required any major changes no matter what elevation Ive been to. F&F requires a little more idle mixture but the rest stays the same. Hope this helps. Thanks for the help. FjR68

[Frank]

Went with the more volume same psi pump. Two new filters and whamo ! Shes back Had to lower TPS to clean up bottom end, which in turn lowers the whole mapping from idle to WOT . I dont think the other pump was working right from the box it came in. I have so much more adjustment to it now than ever and seat of the pants , it feels like there is way more power on tap than before. Im happy again . Thanks Mike for the help. FjR68