Thanks for all your thoughts on this problem. Just reporting back to say it's been fixed. Turns out I had two bad relays (fuel pump relay and the ecu relay). Once both were replaced, the stalling and hard restart problem cleared up. 20 years is a long time for those relays to work - pretty impressive, actually. And I figured out why I was hearing what I thought was the fuel pump run continuously when I just replaced the fuel pump relay. It was actually engaging the idle stabilizer faster than my old relay, so I mistook the idle stabilizer buzzing for the fuel pump buzzing.

All cleared up now - on to the next thing (cleaning gunk under the luggage rack and putting little screens in the drain holes - that should be fun)

Mark

On Sun, Jul 18, 2010 at 9:20 PM, Scott Daniel - Turbovans < scottdaniel@turbovans.com> wrote:

> If you are 'sure' that the thing that keeps it from firing up is lack of > fuel pump running ... > you're on the right track with the fuel pump relay .. > though if your used one made the fp be on steadily ...that's sure not > right. > > IF ...it is simply a matter of fuel pump control...no parts like oxygen > sensor etc are involved.. > Listening for the fp to pre-run is a very good habit. I do that every time > I fire up any vanagon. > > there are only a few requirements to make that happen .. > power to the ecu, and ecu supplies ground to the fp relay to energize it, > to run the fuel pump. > power for the fuel pump comes from the main relay I believe ....consider > that part. > > if nothing else, at least to sort through the weirdness, I'd rig a manual > fuel pump switch temporarily .. > so that you can get 12 V to the fuel pump 'for sure' . > > if it's as simple as no power to the fuel pump ...that shouldn't be 'too > hard' to fix. > > if it's something else...say pump runs but there's not suffecient fuel > pressure, that's anohter story of course. I like to have a fuel pressure > guage on them while sorting through stuff like this. Currently I have on > between the front seats, but running fuel through the van like that is a bit > scary .. > and the engine cover doesn't close perfectly ....and heat gets in the > cabin, but by golly, I am sure there is fuel pressure on this one van with > an intermittant igntion problem. > > it would be nice to have another ecu. I have heard of one that would not > supply ground to energize the fuel pump relay, but only one. Usually they > are very good about that. > > if you are sure the pre-run feature is not working ....just work on that > and it shouldn't be that hard to track down. > once past the pre-run feature, , the next time the fuel pump runs is during > starter cranking .. > and ecu knows the engine is cranking due to seeing ignition .. > like if you take another distributor and plug it into your harness, turn on > your key, and turn that distributor with your fingers, you should hear the > fuel pump run then too. That's a nice test to do .. > shows that the entire fuel pump control circuit is working. When I see > fuel pressure also during that test, then I know that whole part of the > system is working like it should. > > seems to me that if the fuel pump won't pre-run, and it won't run during > cranking ... > and you are sure it's not pump or electrical connections for it ... > my mind goes to the two relays and the ecu. > > I believe in redundency for the sake of not getting stuck anywhere, and so > far I have not had to arrange a back up fuel pump power supply ........but I > sure would for any excuse . > As far as I am concerend they should have two complete redundant and > indepedent fuel pump power supplies, plus manual back up. > > the two relays are identical I think. > and it is amazing how many of these 20 year old relays work so reliably. > wouldn't be a waste of money to one or two high quality new ones in hand. > > I wouldn't dismiss the igntion switch either, even though it is new. > I just found one the other day .. > great starter cranking ...but no igntion during cranking. > > Scott > www.turbovans.com > > > > ----- Original Message ----- From: "Mark" <mbrush@GMAIL.COM> > To: <vanagon@GERRY.VANAGON.COM> > Sent: Sunday, July 18, 2010 5:54 PM > Subject: stalling and hard restart > > > > After new fuel tank, pump, filter, lines, ignition switch, temp II switch, >> a >> few ground wire clean ups, and an adjusted throttle switch - things are >> running MUCH better - BUT - I still have a problem. After driving for a >> bit, the bus will eventually stall and then have a really hard time >> restarting. Usually happens after I've driven it, get back in and I'm >> idling to leave a parking lot (STALLS). It's happened often enough that I >> can tell when it's NOT going to restart. The telltale sign is I don't >> hear >> the fuel pump engage for those brief seconds when I turn the key over >> (before I turn it all the way over). If I don't hear the fuel pump, when >> I >> turn it all the way over, it won't start. I keep retrying it until I hear >> the fuel pump cycle on. Once I hear that, the bus fires up. This >> happened >> with the old pump AND the new pump (though the new pump sounds a lot >> better >> when it cycles on - the old one seemed to struggle). >> >> It happened today, and I tried replacing the fuel pump relay with a spare >> I >> have. When I put that relay in, the fuel pump just cycled on continuously >> (not for the 3 or 4 seconds as normal). It didn't start. I put the old >> relay in - a few more tries - I heard the fuel pump cycle for a few secs - >> and it fired up and got me home. >> >> I know all the FI parts are interconnected, so it could be a bunch of >> things >> (O2 sensor, idle stabilizer, ECU??) - just wondering if this sounds >> familiar >> to anyone, or if anything comes to mind. >> >> Having fun learning how this machine works - but my machine is telling me >> that I have A LOT more to learn :-) >> >> Mark >> >> -- >> Mark >> 1990 Westy (2.1 - manual) >> > >

-- Mark 1990 Westy (2.1 - manual)