Careful when getting hoses from AB.

Some of them are URO parts...i.e. cheap chinese garbage.

Learned about them when redoing the coolant and PCV hoses on a volvo s70.

Google "volvo uro crap" for some examples

 

I can't remember the brand sticker it had on it, but I know it was non-genuine. I knew better than to go that way, but since it had already been done, I was reluctant to replace a hose that had just been replaced.

I bought genuine hoses for everything but the straight lines. For those I bought Gates premium line from Napa.

There's some "genuine" stuff that I won't pay for because the price for NOS is outrageous and there's an OEM/OES part for far less. But I've been burned on most of the non-OEM/OES replacement parts I've bought. Apparently they're just for mechanics to be able to offer estimates that anyone can swallow or for people who want to fix something cheap and flip the car to the next sucker.

Back to the topic at-hand, I think I've ruled-out the VSS, vacuum leaks, plugs and wires. What else can I check?

 

I pulled 1, 3, 5. Something going on with 3.

 

so I tried fiddling with injector 3. It's hard to reach under the plenum upper, but I turned it around a little, sprayed out the multiplug from above, blew it out the area with the air compressor, jiggled it... that's about all I can do unless I pull the plenum.

Should I pull it and order an $82 injector? or hope that I can rehabilitate the one in there?

At this point I'm betting a jet of hot coolant blasted the injector and it's stuck. As pressure bled down, the jet changed angle and was pointed more toward the ECT sensor by the time I popped the hood.

I really have no idea though. I'd hate to replace the injector and then still have the problem.

 

ok, so I managed to pull the multiplug on injector 3. I ran the engine and it doesn't pop out the intake anymore. Of course it sounds like it's running on 7 cylinders but at least it's not popping.

Looks like my job for tomorrow is to pull the plenum.

Is there a procedure to test an injector? Can I hook it up to 12v? Can I pull the pump fuse and watch it working/not-working on the harness?

 

You are on the right track I think, it is not the VSS since you unplugged it and the problem continued.

 

The injectors get plus 12 volts from the harness, and the ECU grounds each one as required to make it activate. You can compre ohm readings from one injector to another, as an example.

 

Update on this for future reference:

It turns out the spark plug indication was due to a dumb error mixing up plug wires at the back of the motor. When I made the first post, I indicated the plugs looked normal, which they did until I screwed up the re-wiring. That was terribly embarassing but I recognized my error back on the 5th and once that was fixed the original problem has persisted though.

The problem with severe misfiring has continued but only intermittently and with decreasing frequency. All other times it runs as if nothing was wrong at all. And when it does act up, it does so for a brief period and then suddenly runs right again.

When it's running bad, it idles nicely but when I give it throttle, it will only take so much throttle angle and then it just stumbles. So it will idle, or I can just crack the throttle and get up to about 30, but if I try a half-open or more throttle then the motor just bogs and gags.

But at this point I'm experiencing the problem more and more rarely. Hasn't happened today at all. Monday, only once briefly. Sunday it happened once and I just drove it around slowly and then it ran well and I got on the highway and drove it a long way with no problems.

I have some suspicion about water in the fuel. We had a big rainstorm prior to a fill-up that occurred just before the problem started. My other theory is something with the IACV.