QuestionHoward,
So, previously we have covered that I have good to great compression, had drained both tanks and found red varnish, and only re-filled the left tank, as the right one leaks, and am in test mode on left tank only. The fuel pump is LOUD, can be heard from driver seat, or outside trunk when running. You noted the filter must be partially clogged, and I replaced that Monday night, only to return to a condition of solid idle, but no power at throttle. I ran the timing light, borrowed from a friend tonight, and it is dead-on 17 degrees BTDC. So, it seems I have a fairly health engine, and a fuel delivery problem. It'll be a couple of days before I can get to Harbor Freight to pick up a fuel pressure and vacuum tester, so in the interim, I ask would it be your experience that the fuel pump may be struggling due to debris either in line before, or after it, and possibly the new filter was fouled right away due to such debris? I plan to begin disconnecting, and flushing fuel lines, but can a pump be cleaned out, or is it likely to need replacing? Lastly, I want to be thorough without overkill, so is it to be assumed that the filter is the choke point, and I need only begin my clearing lines from tank, to changeover valve, to pump, to filter, but not so much beyond that at this point?
AnswerIt is a waste of time guessing. Testing is the ONLY method to arrive at any conclusion. If you checked the pump and main lines to see that they are not vibrating against metal and the fuel pressure is correct, you may have a pump warring out as they do make noise when they get old as well as clogged lines, filter and tank pick up.
You need to know that the fuel pressure is correct at speed as well as idle. Also you need to know what the intake vacuum is under acceleration and at speed. It must never go below 5 in hg. and the fuel pressure must stay at about 32 PSI running and as high as 42 PSI under hard acceleration.
Howard
