SERPENT said:
Thanks for your input. We are doing a dyno run today to look at fuel pressure at the rail. At WOT we are hoping for 90 psi or better.We had to fashion a pressure guage to the end of the rail as there was no fitting to tie into. Now iI know that this is not a measure of volume but we are trying to narrow down the problem.We have also suspected a problem in the split second box.One fuel pump turns on for only 3 seconds and the second turns on for about 10.Boomer flashed the split second box for us a couple of months ago but I believe he only adjusted timing. We have now jumped the pumps to maintain fuel pressure ---any thoughts.
You are doing what is necessary to narrow it down.
Jumping the pumps will tell you what is happening, with the gauge readings under high RPM, full throttle pulls.
There is a pressure volume test that can be run = a certain volume at a certain pressure for a measured amount of time. I have no idea what that would be on one of these systems, so the way you are doing it is perfect.
Please continue to post on this thread so we can all benefit from your experiance, and how and what you are finding as you go.
You may have to eventually go to a bigger injector, with an upgraded fuel system.
I as well as many others are using, or are going to use the VEC 3 for fuel and spark management, and not use the split second box, or FMU.
This gives us much more adjustability and control.
Also we do not have to run the fuel ressure up to keep from being lean (this does require an injector change). Better a more constitant spray pattern.
In the red truck I will be running about 9-10 PSI of boost on a 540 CID motor, and I am using a 75 LB set of RC injectors that are flow matched. They are pricey at 100.00 a piece but they are very good and have a great pattern.
I had a Vortec blower on a 1998 Ford Expedition 5.4, and it only had an FMU, which worked flawlessly for 112,000 miles. This was only at 5 PSI (no intercooler) so they do work.
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QuickSilverIt's real nice having you (Jack) hanging around.....Happy New Year Jack! :rock:
Quick
Thank you very much, it is nice to hear things like that, makes me feel good.
Happy New year to you also, nice to have you here.
You are one of our most senior members.
Thanks for keeping up, adding to, and putting up with the nonsense.
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Ram From HellAlso, if you have injectors that are too large for your application, you'll have other issues. Short duty cycles and/or low pressure to compensate for their flow will lead to poor injector spray, which kills atomization.
Exactly............:rock:
I am having to run a 1600 LB injector (at 60 PSI) on the silver truck motor so I will have very short pulse width (duty cycles) at idle. Again I am going with an RC injector as they have the best spray patterns. The 1600LB injector runs 198.00 per injector (I hope they are worth it).
It might be a little dirty emmissions wise also, .800+ lift camshaft doesn't help either.
But I did not want to run 2 injectors per cyl and have to put up with the tuning nightmare that staging them would precipitate.
I could stage them as I am running a Motec M800 box for engine management and traction control.
If I cannot get enough low speed control, I will have to add another set of injectors to the manifold, and stage them.
That will require another injector harness to be made up, another set of fuel rails, and more plumbing.
I really don't want to spend the money for all the hardware and have it look like Captain gizmo's whatthef#$%kisit under the hood.
My philosophy has always been, "parts that are not there, never break, or fail".
