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I have a 1997 Chevy Suburban and I'm pretty sure that the fuel pressure regulator valve is going/gone. Or maybe it's just the elevation.

We recently had the water pump and the front intake manifold gasket replaced. Before that we didn't notice any trouble starting, but since then (just over a month ago) we've been having intermittent trouble starting it. Typically it starts a little rough in cold weather.

We travelled from Arkansas to Utah, so there's a huge elevation (and a fair amount of temperature) change. In Arkansas we attributed the trouble starting to the battery (it ran down a few times because children+dome lights have a tendency to do that), but since then and especially in Utah it would take quite a while to start. Sometimes several seconds of cranking. Occasionally at low RPMs (pulling out of the driveway once, a few times in a parking lot) the engine just dies. When we were pulling out of the driveway we were nose down at a slight incline (maybe 3-5%). It actually wouldn't start after several seconds of cranking. Finally we pushed it back into the driveway (10-30s), and then after a few seconds I tried again and it started.

At low RPMs it's really rough, sounds like it's going to choke and die. But revving the engine a bunch will kind of smooth things out. While driving at speed there are no problems.

The thing that leads me to think that it could be something else is that the fuel gage is wobbly. Fairly often it will just start waving wildly back & forth, which I've read could be a problem with the fuel pump.

Does this sound like it's the fuel pressure regulator that's at fault here? (unfortunately the thing is inside the engine, so it's not exactly easy to test).

  • Sounds to me like an idle air control valve/motor. Does it start easier if you give it a bit of gas? Try holding it at about 1/4 throttle when you start it. What RPM does it idle at when cold? Does it idle better when it is warm? – rpmerf Jan 4 '17 at 19:47
  • Not usually - I've tried pumping the gas. Next time I start it I'll try a 1/4 throttle. It idles ~500RPMs. I haven't noticed if it idles better when warm - after we've been running for quite a while it usually does, I think. Haven't been doing much stop & go lately though. It has died when pulling up to a traffic light or something, but that's been pretty rare. Only once or twice that I can recall. – Wayne Werner Jan 4 '17 at 20:51
  • 500 should be fine when it is warm, but it should be closer to 1000 when it is cold. – rpmerf Jan 4 '17 at 21:05
  • I'm pretty sure a normal idle on a Gen I SBC should be between 600-700 rpm, so 500 is a bit low. The "spider" fuel injection is something I've never dealt with before, though I've been hearing about it used on a few different GM models. I've not heard good things about them, though. – Pᴀᴜʟsᴛᴇʀ2 Jan 5 '17 at 1:16
  • See if you can get a fuel pressure gauge hooked up to the high pressure line; it will tell a lot. If the pressure is too high, the diaphragm isn't opening up properly. If it's too low it's stuck open or your fuel pump is going out. If it's right but doesn't hold pressure for very long after shutting the engine off, it's bad. Also, change your fuel filter if you haven't already! It's cheap, (probably) simple and something that needs to be done regularly anyway. – atraudes Jan 6 '17 at 0:34
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After a few months we were on another road trip, hit a bump, and the fuel pump totally went out. It's possible that this was just a sign that our fuel pump was dying.

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