'95 Chevy Astro van - no start

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  #1  
Old 12-11-05, 05:02 PM
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'95 Chevy Astro van - no start

This thing is really getting old. My friend says her '95 Astro (4.3-liter W-engine, 117K miles) won't start. I went to check on it, and have left a battery charger on it for overnight, since it had run down with extended cranking on it. I did retrieve a code 32 from the MIL flashes. Mitchell and Alldata say this a "universal" EGR system/circuit code, set for any EGR malfunction. At first, I was thinking maybe the EGR valve was hung open, causing low vacuum and the no-start. Then I thought, a fuel-injected engine shouldn't have the same vacuum requirements as a carbureted engine, at least not to get started, since the vacuum isn't responsible for pulling the fuel through the carburetor. The last time I checked it, the fuel pump was making 62 psi with the engine off, 58-59 psi with the engine running. I haven't checked it again yet, but that's on my list. With the miles on it, a fuel pump could certainly be the culprit. Am I right about the vacuum thing, though? I'm sure the van needs a new EGR valve, but I can't see how even a wide-open EGR would not allow the engine to start. Input/advice is always appreciated. Thanks in advance - Chris
 
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Old 12-17-05, 04:47 PM
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I would recheck your fuel pressures. Have someone try to srart the van while you bump the fuel tank with a mallet.
 
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Old 12-18-05, 05:38 AM
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Thanks, Mr. Dummas. I plan to head over today with a fuel pressure tester and look at what the pump is doing. However, I was over yesterday and gave the key a twist to verify the no-start condition. After trying to start a few times, the smell of unburnt fuel in the garage was almost overwhelming, leading me to believe the injectors are spitting fuel. While cranking the engine, though, it would "sort of" hit, like it was trying to start, but not succeed. The other times in my 30-some-odd years of bending wrenches that I've seen this was when something had gone wrong with the timing chain/drive system. That's on my list to check, too.
I'm still curious as to my question about vacuum in a fuel-injected engine. Anyone who can provide technical insight, please give me your opinion. Thanks again, Mr. Dummas. As soon as I know more, I will update. 'Til next time,... - Chris
 
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Old 12-20-05, 05:43 PM
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Okay, here's the latest. Static fuel pressure is 62 psi. Distributor turns with starter turning. Engine makes the same sounds it always has while cranking; doesn't sound like it's turning easier or harder. Coil fires to ground while cranking. I had no way of checking for spark at the plugs tonight, but I will tomorrow.
My supervisor at work says he had a '92 S-10 with a 4.3l v-6 that wouldn't start because of a defective oil pressure switch. I wonder now about two things: could the timing chain have jumped far enough on the sprockets to make the engine not start;and, does this engine have a low oil pressure no-start switch, and if so, where is it?As always, Any/all input is appreciated. Thanks again - Chris
 
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Old 12-20-05, 08:33 PM
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ok...regarding your vaccuum question. I'm not sure if this is the "technical" answer that you are looking for, but a fuel injected engine DOES still need good vaccuum because if you have no vaccuum then you have no air intake, and if the injectors are still spraying fuel but there is not enough air coming in then you will flood and this could cause your "no start, but occasionally 'tries' to" condition. 62psi is plenty of fuel pressure so I would rule out the pump for now.

The reason your supervisor's car would not start due to a defective oil pressure switch is because on many chevy trucks the FUEL PUMP is run off of the oil pressure switch (except for the momentary prime when you turn the key on). This is designed this way so that if you lose oil pressure the engine will automatically die instead of letting you drive it until it locks up. Check to see if your oil pressure guage rises during cranking (or see if the light goes off if you don't have a guage) The oil pressure switch is usually located right beside the base of the distributor at the back of the intake....if it is not there it might be right above the oil filter.

tip: if you suspect that the engine might be flooded hold the gas peddle ALL the way to the floor while cranking (called de-flood mode) and the injectors will not inject until the engine starts.
 
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Old 12-21-05, 05:46 PM
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Thanks, fallen4shell. The oil pressure gauge on the van shows pressure rising while cranking the starter. When the sender is disconnected with the key on, the gauge shows way past maximum on the scale, so I'm led to believe the sender is working. While looking at the van today, though, it seemed to reach one spot while cranking where it offered a little more resistance than everywhere else. I'm beginning to wonder if maybe the timing chain has slipped on the sprockets just enough to throw things off. Duh, one tooth off is off! I think this is where I'm headed, unless someone has a better idea. More news as it develops. Thanks again - Chris
 
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