Well, I got the walbro pump installed and I thought my problems with the engine breaking up /backfiring/losing power over 5,000 rpm would go away. Well, the popping,/backfiring has gone away
but I still notice that if I let off the gas just slightly )say 3 degrees on the throttle plates) it pulls much stonger above 5,000 rpm.
You can floor it to 5,000 and it is awesome but if you stay on it, it loses power but if you back off just slightly, it will pick up again and head up to 6,500rpm. WTF??
I have tried the fuel pressure all the way up and all the way down and it dosn't make much difference.

My BLM's are good all the way up.
My "tuner" has burned 3 additional chips (we did 8 orginially) and he added fuel to table 2 volumetric eff. adder with numbers of 55.5@5,200, 53.0@5,600, 44.3@6,000 and 35.1@6,400, but I don't understand this well enough to know if its an issue. Should we add more fuel here or is there some other problem?
Seems like a WOT problem only and we just can't seem to get it right. I have thought of adjusting my throttle linkage so it only opens part of the way, but there has to be a better answer.

Help!!! I need some ideas. Thanks..................bob

 

sounds like you need to monitor your AFR in PE mode. You may have too much fuel added!!! What is the o@ voltage on the scantool? Run at WOT/full-throttle for as long as you can on a steep hill then SHUT-down the engine at 6500rpm ish and pull over to the side of the road , being careful as you loose power steering and eventually, power brakes!!!!!! Then, after cools a bit, pull a plug and see if black or white (rich or lean) and you'll get a better idea of what is going on.

randomly adding fuel where you "think" it belongs is a big no-no, and it sounds like what your buddy did, trying to help of course.

Be careful. If you are at all unfamiliar with what will happen when you turn your engine off (like not locking the steering wheel!) DO NOT ATTEMOT THIS. Do the other monitoring ting, ven a voltmeter tapped into your O2 line at the ECU. Using a scantool or WINALDL would be best, obviously.

Good luck.

 

WOT me worry?

 

Fast, my O2 voltage has been in the 875/900mv range consistently at WOT. We added fuel after extensive runs at various rpms in 400 rpm increments. We were lean above 4800 per two different scan tools (vetronix and auto x-ray) so added 5% more fuel at higher rpm ranges where lean conditions were indicated but no help (although it helped from 4,000 to 5,000 rpm) Wot AFR are currently 11.7 @ 4,800 rpm.
I like the plug check you suggest. I used to do that kind of test
in my carb days so if its clear cut, ie black plugs VS white plugs I can probably get an idea.
But you know, if it was a rich or lean problem, changing the FP should have had an effect don't you think? It didn't and I ran it all the way up and all the way down and my BLM's were either way rich or way lean depending on fuel pressure and no change in the problem.

Thanks for the ideas. I guess you think its a prom issue as do I but I am not getting much help from the "tuner". THATS WHY YA GOTTA DO IT YOUR SELF, PERIOD.................bob