Thursday, June 6, 2013

Back at it

After a bunch of time on other things, I'm finally back at the Volvo.  There is really very little to do before firing it up, but it's been very slow going.  Here's what's happened over the past few days.

Before pulling the engine, I encountered a sudden loss of power.  The car would run fine for a while, then experience a significant loss of power.  If I pulled over and let the car idle for a bit it would recover and I could drive another mile of so then the whole thing would repeat.  It seemed like fuel starvation, so I wanted to go through the fuel system to check for blockages etc.  I drained the tank, pulled the pickup screen, inspected the tank through the tank sender opening, and blew out all the fuel lines.  Everything looked really good, but I noticed something odd with the pickup screen.  The screen slides over the pickup pipe, but there is nothing to stop the screen from going on so far that it bottoms out against the pipe end.  When it bottoms up like that, I could see it blocking the pickup.  And the more the pump sucks, the harder it will hold the screen against the pickup opening.  It seems like a plausible cause for the problem I encountered.  Not certain, but possible.  After some head scratching I came up with what I hope is a good solution.  I found a couple of o-rings that fit snugly over the pickup pipe.  The screen then pushes up against the o-rings as it rides up the pipe.  I'm counting on the drag from the o-rings to keep the screen from riding up too far and choking off the pickup.  I have no idea how this is supposed to be set up, but my guess is that the screen is supposed to be a tighter fit on the pipe to provide the same drag/friction that my o-rings are providing.

Then there was lots of misc reassembly needed.  Radiator, shifter, new fuel injection harness, heater hoses, throttle including new throttle cable, electrical hookup to starter and alternator, etc.  Then fill the radiator and fill the engine with oil.  Don't want to start without oil!

Given the suspected fuel problem, I wanted to confirm proper fuel pressure before trying to start the engine.  I hooked up my trusty gauge and turned on the ignition, and no pressure.  Not just low, but none.  I spent a bunch of time messing with the gauge thinking it was hooked up wrong, but when I finally disconnected the fuel line and ran the pump, there was just a trickle of fuel.  It should be a steady, solid flow.  So, I started working back to the pump and found nothing coming out of the pump.  This is the new (rebuilt) $350 pump that was just put in a year and maybe 300 miles ago.  So out comes the pump and the pickup flow from the tank is good, so the problem appears to be in the pump.

Well, the outlet of the pump is a check valve which is removable.  I took it off and tried blowing through it and it wasn't easy.  I then notices a bit of the spring sticking out of the end of the fitting which didn't seem right.  So I worked that back into place and things seemed "maybe" a bit better.  Anyway I screwed around with this for an entire day including dealing with a corroded fuse which caused the pump to stop completely.

But the good news is that by the end of the day the pump was working, pumping a good flow of fuel, and making 30 PSI as expected.  But this check valve issue could also explain the running problem that I had.  If that spring worked it's way out then I might still have a problem waiting to happen again.

Now the bad news.  After the system pumped up to 30 PSI I shut off the pump and heard a hissing sound coming from the injectors.  Called it a day and went back out in the morning for a fresh start.

The same problem happened again in the morning.  Feeling around the #1 injector the sound changed as I held my hand over the injector seal area, so I think I have a leaking injector installation.  I had trouble getting one of them in, so I need to go back and fix it.  But the bigger trouble is that when I pulled the connector on the injector, the hissing stopped.  I could hear the others hissing too, though much quieter because they are sealed properly, and that sound stopped when I pulled their plugs.  So I think I have injectors which are on all the time.  Sounds like a wiring harness problem, or more likely I hooked something up wrong.

Gotta go off to some other things for a couple of weeks, but with a mess like this I need a break and a fresh start to sort it out.

Oh, one other thing I got done in the intervening time.  I pulled off all the wheels, stripped the old tires, got the wheels painted, and mounted and balanced new tires.  Once I get it running, it should be a like-new car.  Can't wait.

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