Weird intermittent crank no start
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Weird intermittent crank no start
Hello. New guy here and Family Mechanic !! Grandsons ‘p5 civic ex 1.7 had overheated and he ran it hot ! Bad head gasket so I removed head and checked installed head ! Before the overheat problem the car would start right up ! After the head install it wouldn’t start . Crank and cam sensors have 12v ! Somewhere in the diagnosis I noticed that when I plugged my scanner into the dtc it would fire up ! If I removed the scanner it wouldn’t start ! I then received a code for intermittent crank sensor signal ! With car running and code scanner connected I went to the crank sensor code and erased it , as soon as I erased it the car shut off !! Also I did install a new crank p sensor after the head gasket/no start but remember the old sensor was fine before gasket . I cannot find a download wiring diagram so I can follow where feeds what ! Thanks
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Re: Weird intermittent crank no start
Car starting only when the scanner is plugged in usually indicates a ground issue. Since you had the head removed, check all the grounds under the hood. It's possible you missed reconnecting one. Specifically where the engine harness connects to the water neck on the block near the upper radiator hose. Also the ground jumper that goes from about the same area to the radiator support.
Last edited by BrotatoChip; Oct 7, 2022 at 03:17 PM.
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Thanks I have checked under hood but haven’t seen any obvious problem but you are absolutely correct about grounds ! I am going to try and download a service/repair manual for ground points . Would you know where I can find a manual ? Agree about the head off/on then having the start problems ! I worked on a Chrysler Pacifica for literally 4 months looking for no start ! Ended up a ground wire under the tpm was in place but corroded off connection !
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Go to the most recent link here
https://www.civicforums.com/forums/1...king-7th-gen-s
https://www.civicforums.com/forums/1...king-7th-gen-s
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This post's first entry defines the various grounds.
https://www.civicforums.com/forums/1...t-install.html
https://www.civicforums.com/forums/1...t-install.html
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BrotatoChip I did miss the ground You mentioned by water inlet ! I actually cleaned that ground while getting ready to install the head but it got tucked down and I missed it ! Anyhow It did start right up without scanner on but still in limp ! When the car wouldn’t start after the new head gasket I figured the crank sensor was bad and replaced it with a cheap one and I am getting the crank sensor intermittent code ! I am thinking the Denso that I replaced is probably good !
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