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Intermittent no-start 3.1L
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Proa42
User
Aug 18, 2010, 6:52 PM
Post #1 of 5
(1510 views)
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Intermittent no-start 3.1L
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I have a Lumina APV with a 3.1L. It will start when cold. Once started, I run the engine to operating temperature. Once turned off and let stand for a while, it will not re-start until it has cooled below what appears to be 1/4 of the gage.
New Fuel pump, distributor, alternator, TPS, MAP sensor, Temperature sensor, ecu.
Has fuel.
Who can solve this puzzle. It's my only transportation.
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 18, 2010, 6:54 PM
Post #2 of 5
(1505 views)
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Re: Intermittent no-start 3.1L
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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 tested 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) If all of these things check good, then you would need to do a complete compression test.
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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Proa42
User
Aug 18, 2010, 7:02 PM
Post #3 of 5
(1500 views)
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Re: Intermittent no-start 3.1L
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Engine has TBI, functional
Runs great once started (cold). I get 23 MPG hwy, and loaded (when it starts)
I know part of the ECU program is affected by the change in temp (at about 133 degrees) affecting timing, EGR, and other functions.
Compression, fuel and spark being within limits, what else could it be?
Has new coil too.
(This post was edited by Proa42 on Aug 18, 2010, 7:04 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 18, 2010, 7:07 PM
Post #4 of 5
(1497 views)
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Re: Intermittent no-start 3.1L
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Apparently you don't need me. Good luck.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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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Sidom
Veteran
/ Moderator
Aug 18, 2010, 8:03 PM
Post #5 of 5
(1489 views)
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Re: Intermittent no-start 3.1L
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There is too many possibilities to guess. You've given some good background info but now to find the problem, you need to find out what is missing spark or fuel. To fine tune it even further after that, some basic systems need to be tested as well, to confirm they are functioning....'
HT has a pretty good chart that will rule out a lot of stuff and get you very close to the problem.....Down side is....it can be a PITA to run but without these answers we can't really help you....
It's hard enough finding a problem with the car sitting in front of you in your bay........
You should try it online when you can't even touch it.....
BTW knowing what year it is would help to.....
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