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Engine troubleshooting?? Help?
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94Buick
New User
Sep 16, 2009, 4:30 PM
Post #1 of 2
(1346 views)
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Engine troubleshooting?? Help?
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I have a 94 Buick Lesabre that runs excellent but after it runs for a while and I turn the engine off it wont start right away. It will take anywhere from 5 min to an hour to start again. More recently the car has been dying and wont start for a while like my previous problem. But if I wait a while it will start back up just fine and runs ok until it dies again which varies from 5 min from starting to a few days. I was advised it could be the crankshaft position sensor or the cam shaft position sensor and I have replaced both of those and I still have this problem. Any recommendations on what this problem could be?
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 16, 2009, 4:35 PM
Post #2 of 2
(1343 views)
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Re: Engine troubleshooting?? Help?
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All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be test during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.
Every engine requires spark, fuel and compression to run. That's what we have to look for.
These are the basics that need to be tested and will give us the info required to isolate a cause.
1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.
2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.
3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.
4) Perform a complete compression test and record the results. All cylinders should be over 120lbs in most cases and all be within 10% of each other.
Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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