1993 Chevy Van Do I have leaky valves?

Tiny
SHADETREE0790
  • MEMBER
  • 1993 CHEVROLET VAN
  • V8
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
OK, so here's the story. My van was running fine but was long overdue for an oil change. Took it to jiffy lube cause I didnt feel like laying in the snow to do it myself. They changed the oil and flushed the tranny and replaced the tranny fluid. When I got it back, I decided to do a basic tuneup on it. Spark plugs, wires, distributer cap, roter button, oxygen sensor, air filter, fuel filter, fuel injectors, fuel pressure regulator, thermostat. Also I was having a problem with the heat so I changed the heater core. The van started running rough and I thought that it was a vacume leak. I checked all the vacume hoses and they were ok. Replaced the throttle body gasket and the map sensor. Still runing rough at idle. Problem has gotten worse and now the van wont start at all. I took the plugs out one by one and double checked the gap on them. Gap was fine but in less than 100 miles the plugs have a lot more carbon on them than I would have expected and came out wet with gas. Oil smells like gas too off of the stick and it is pretty black already. I have not done a compression test because I dont have the equipment to do so yet. Any ideas?
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Friday, February 20th, 2009 AT 9:54 PM

3 Replies

Tiny
JACK42
  • MEMBER
So it was running ok before you tuned it up? Need to locate which cylinder is missing first. Use a water bottle to spray the exhaust manifold ports to see which one is coldest. That will be the misfire. Once you know which one it is, try checking the plug to be sure it isnt cracked, that can cause a miss. Did you swap over the ground strap in the distributor cap for the coil? If not it will cause issues too
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Saturday, February 21st, 2009 AT 9:05 AM
Tiny
SHADETREE0790
  • MEMBER
Jack I tried to pm you but I dont have enough posts on this forum. The van does not run so I cant unse that diagnostic technique to find out what cylinder is missing. Also I have never heard of a ground strap in a distributer cap. Could you give me a little more info on this. I have not checked for spark because I dont have a new plug to use, but I am getting fuel, so it either has to be a spark or compression issue.
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Wednesday, February 25th, 2009 AT 1:27 AM
Tiny
JACK42
  • MEMBER
I prefer to answer in the forum(here), that way I can refresh my memory on your vehicle. You can use a spark tester or screwdriver held off theintake manifold a little bit to check for spark. Does this van have an HEI distributor? (Large cap) If so there should be a ground that goes to the coil from where the electrical hooks up
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Wednesday, February 25th, 2009 AT 7:41 AM

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