Car has trouble starting sometimes, runs rough

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  #1  
Old 11-12-09, 04:05 PM
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Car has trouble starting sometimes, runs rough

I have a 1989 chev celebrity. In the mornings it takes several cranks to get it started. It will turn over and sputter several times before finally starting and running just fine. It will then start right up once turned off.... However I am a mailman and after about an hour of delivering ,mail if I shut it off when I restart it it runs very rough, idles rough. It will continue to do this and when I shut it off to deliver some apartments (takes about 30 minutes) WHen I try to start it again it will initially crank up then after a second it will quickly start missing until it finally dies and then I have to wait about 30 minutes before I can start it again, after it eventually starts, it runs perfect, no misses! I am a CLUELESS!!! I have replaced coil packs and plug wires and plugs. NEED HELP! ( oh yeah and the check engine light isnt on! so no code to make it an easy fix!)
 

Last edited by sparkant; 11-12-09 at 04:09 PM. Reason: forgot to say no check engine code
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  #2  
Old 11-12-09, 04:25 PM
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When you start it cold, use a small amount of starter fluid down the throttle body and see if it takes right off.

Then while it's idling rough, pull plug wires one at a time and see if it isolates to one particular cylinder.

Then go to your EGR diaphragm port and apply vacuum to it while it's idling rough and follow that by taking the vacuum off. See if it makes any difference in the idle.
 
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Old 11-12-09, 05:30 PM
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Is this only a basically cold idling problem? Or will it also die when it is stumbling, if you sit and give it gas? Or does it actually start running fine if you throttle it, but then die again if you let the foot off the gas?
 
  #4  
Old 11-12-09, 06:38 PM
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No, not just a cold problem. Once I finally get it started in the afternoons (after it is warmed up and having problems) I have to pump the gas constantly and after going 0-60 in about literally 3 minutes, it just hits all of a sudden and its ok from then on. Sometimes when I pump the gas it just slowly sputters until it dies. If I just floor it from the beginning it dies almost immediately. It's very frustrating.
 
  #5  
Old 11-13-09, 05:09 AM
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In a fuel injected engine, "pumping the gas" doesn't do what it does in the carbureted engines. The latter have the accelerator pump which feeds extra fuel every time you push the accelerator. Doing the same thing on a computer controlled engine will just send a number of different throttle position/manifold vacuum signals to the computer.

Do what has been suggested and post back along with the engine size.
 
  #6  
Old 11-13-09, 03:31 PM
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Ok, This morning, first thing I did was spray ether in it, started right up, then I checked the spark indivdually, all had very strong spark. Now, could it be some kind of cold start sensor affecting both problems or are the 2 related since one is a cold start prob, the other is a problem starting after it has warmed up and making it run rough. Tried the EGR thing, no difference. Oh, yeah, and the engine is a 2.8 v6.
 
  #7  
Old 11-13-09, 03:45 PM
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With the ether - that moves you in a direction. A problem in a temp sensor (for the computer) can cause cold start problems, although that usually clears up after the engine is warmed up.

When you were pulling the individual wires it was to check for more than just the spark from each wire. It was to see if the problem could be isolated to one cylinder. That would include fuel injector, valves, etc. When you pull a wire on a cylinder that's "pulling its share of the load" the idle would get rougher. Should you find a cylinder that didn't make any difference that tells us the problem, whatever it is, is in that cylinder.

I think it would be a good idea to get a fuel pressure test on this thing. A pump or regulator acting up could account for most of the problems.

When you tried the EGR thing what do mean it didn't make any difference? You're saying when you applied vacuum and pulled it back the engine ran the same through the test? If that is what you're saying, then the EGR valve has(and is) the problem.
 
  #8  
Old 11-13-09, 05:30 PM
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Just went thru this on a '98 Bonneville 3.8.... 1st turn of the key it would not start. Second turn of the key it started but spuddered and smoked. This went on for a long time, maybe 6 months. I had already replaced the fuel filter, plugs and wires plus a new crank sensor. Recently the fuel pump and regulator failed... $600 later it's back on the road. Now it starts right up on the first turn of the key and it runs fine.

Check your fuel pressure, also make sure that the fuel isn't draining back in the tank due to a check valve.
 
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