Please tell me what it could be.

Tiny
DONALD STEVE LEE
  • 1999 HONDA CIVIC
  • 99,000 MILES


I have a 1999 Honda civic si with 100,000 miles on it. And it won't start and run unless I pull out the sp sensor alternator Fuse and turn headlight's on or heater on.

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Wednesday, August 15th, 2012 AT 4:20 AM

16 Replies

Tiny
KHLOW2008
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Check for a bad ground circuit for the PCM and sensors.
Are there any trouble codes?

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Wednesday, August 15th, 2012 AT 11:36 AM
Tiny
DONALD STEVE LEE
  • MEMBER

I really don't no where the PCM sensor is but I did chek every ground I could find. After you replied back to me this morning I tried to start it and I got no fire so I put new coil spark plugs cap and rotary button got it running again now I'm back at the drawing bord doing same thing o2 censors did not look like they wer grounding out. And by the way thanks for the fast reply

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Thursday, August 16th, 2012 AT 3:58 AM
Tiny
KHLOW2008
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Are there any trouble codes? Most parts store provides free scanning services.

No sparks are usually caused by a nad crank position sensor, behind the timing belt, inside the cover.

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Thursday, August 16th, 2012 AT 9:05 AM
Tiny
DONALD STEVE LEE
  • MEMBER

2 coeds. Po108 and po420 cadilatic converter has been cleand out. Wide open. Good to have some one to reply to. Can't thank you guys anuff

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Thursday, August 16th, 2012 AT 2:36 PM
Tiny
KHLOW2008
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P0108 = MAP sensor circuit high voltage input. This fault could be the cause of the difficult or non starting etc.

However you have been pulling sensors etc so this could be a false alarm. You would need to reset the computer and try starting to see if any codes are triggerred. You would need prolonged cranking time to trigger codes.

As to P0420, with a cleaned out catalytic converter, this code would be present after every 2 starts. There is nothing you can do about it except treplace the catalytic converter.

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Thursday, August 16th, 2012 AT 2:55 PM
Tiny
DONALD STEVE LEE
  • MEMBER

It runs perfect. If you have the green plug unplugged to the alternator. And the head light high beams on. And the heater fan on. It will idle and per.

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Thursday, August 16th, 2012 AT 5:34 PM
Tiny
KHLOW2008
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Have the alternator checked/tested. Seems it is overcharging causing the problem.

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Friday, August 17th, 2012 AT 10:48 AM
Tiny
DONALD STEVE LEE
  • MEMBER

I bet your right because my driver side axle threw grease and some might have got in the alternator. I'm am going to donate to you guys. Thanks

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Friday, August 17th, 2012 AT 3:16 PM
Tiny
KHLOW2008
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Hopefully that solves the problem and thanks for the donation.

Have a great weekend.

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Friday, August 17th, 2012 AT 3:45 PM
Tiny
DONALD STEVE LEE
  • MEMBER

Hay befor I pull that alternator off is there a voltadge regulator or could it be built in the alternator and you have a good weekend to again thanks for the fast replies

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Friday, August 17th, 2012 AT 4:51 PM
Tiny
KHLOW2008
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Voltage regulator is inbuilt and since you can't have engine running with it connected, you would need to remove it for a bench test.

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Friday, August 17th, 2012 AT 4:57 PM
Tiny
DONALD STEVE LEE
  • MEMBER

Alternator was fine. Like new back to the drawing bord my father in law was the one who red my coeds. I don't mood he did it right but before my car finally choked out he read my coeds and I rote them down and just found them and hear they are. Po116 - p1399 and stored po108 - po420

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Monday, August 20th, 2012 AT 12:42 PM
Tiny
KHLOW2008
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P0116 is a fault with the Engine Coolant Temperature switch. This can cause difficut starting and stalling when engine is warmed up.

P1399 is temporary codes for misfiring.

Others have been explained to you.

Have the ECT checked.

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Monday, August 20th, 2012 AT 4:47 PM
Tiny
DONALD STEVE LEE
  • MEMBER

Hay if I had a bench test done on the alternator it would not tell me if the voltage regulator is over charging would it. Becaulse the (PCM) is used as part of the alternator control system sending a signal to the voltage regulator. I think the alternator is causing this problem I have smoke rolling out of my ears! Thanks

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Tuesday, August 21st, 2012 AT 10:59 PM
Tiny
DONALD STEVE LEE
  • MEMBER

Hay if I had a bench test done on the alternator it would not tell me if the voltage regulator is over charging would it? Becaulse the (PCM) is used as part of the alternator control system sending a signal to the voltage regulator. Don't no just asking. Thanks again

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Wednesday, August 22nd, 2012 AT 3:22 AM
Tiny
KHLOW2008
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It is possible bench test don't tell if it is overcharging and yes, you are correct about the PCM controlling the charging. Apart from the alternator, the PCM can also possibly cause charging faults.

One way of finding out is to replace with a known good alternator and test. A no charging problem is not too bad but an overcharging system is very dangerous as it can take out a lot of electrical components when voltages spikes.

I once had an older model vehicle which had every bulb in the vehicle blown and wasted a lot of time diagnosing as I did not think of all bulbs blowing when lightings did not work.

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Wednesday, August 22nd, 2012 AT 4:39 AM

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