Crank, no start

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ssobol
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Crank, no start

Postby ssobol » Wed Mar 27, 2019 4:12 pm

I'm having the crank not start issue on my '08 Pathfinder (which I recently bought). When it was cold several weeks ago, I had this issue. The engine cranks fine and will crank for many, many start attempts. If the Pathfinder is jumped, it'll start right up.

I replaced the positive battery connector and fusible link block. Also the negative wire to the battery. The battery is an Interstate and is only about 1 year old. I had the battery tested at Autozone and they said it was fine.

I just came back from a 2 week business trip. The day before I left the Pathfinder was starting fine. Today when I came back, it wouldn't start again. The outside temp is in the low 50's. I put a voltmeter on the battery and the resting voltage was 11.7. When I cranked the voltage went down to 8 or 9 volts. I jumpered the Pathfinder and it started right up, but also the voltage only dropped a volt or two and was 14+ when connected to the other vehicle.

So I am trying to figure out the problem. Is it a bad battery, or is there some other problem? Does the ECU repair that I find on the internet (from this forum) fix something that prevents this issue from occurring?

I have been thinking about adding a separate ECU battery (sealed 12v 7-10 AH) and a switch that will allow the ECU to switched to the aux. battery when the engine is cranking for times that it cranks and won't start. The ECU could then be switched back to the main battery for running.

This would involve some wiring, a switch, and a charging circuit to keep the aux. battery charged.

As far as I can tell, my Pathfinder has the original ECU and the original IPDM (white one).

I just want to get this problem fixed, hopefully without replacing a lot of parts at random.

Thanks.


ssobol
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Location: No. VA

Postby ssobol » Thu Mar 28, 2019 8:19 am

FWIW, when my Pathfinder is off (key out of the ignition all doors closed) I measure a current drain on the battery of about .25A. I know that this is some drain on the battery normally in this condition, but is .25A higher than normal?

Thanks.

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smj999smj
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Postby smj999smj » Thu Mar 28, 2019 12:21 pm

Battery shouldn't drop below 10 volts when cranking. Have you had the battery tested? That would be where I would start after making sure the battery connections were clean and tight.

ssobol
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Postby ssobol » Thu Mar 28, 2019 1:28 pm

smj999smj wrote:Battery shouldn't drop below 10 volts when cranking. Have you had the battery tested? That would be where I would start after making sure the battery connections were clean and tight.
I had the battery tested. They said it was good. As far as I can tell the battery is only a year old. However, I have just replaced it anyway. I measured the voltage. I'll let the truck sit overnight and see what the voltage is tomorrow.

weaver
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Update?

Postby weaver » Mon Apr 15, 2019 8:53 pm

Greetings. Any updates? Heck this reply is late so you probably fixed it by now buuuut... I was wondering what the battery voltage is when it's running. My experience is that it should be between about 13.5-15 (about 12.5 with engine off) VDC, depending on the load. That's been the norm on my vehicles over the years. I'm new to an 08 SE, and haven't measured mine yet. I had a problem getting the OEM negative cable clamp tight on the battery as smj stated (the battery post is tapered, the terminal is not, bent and crimped terminal to fit tight). Your battery may not be getting fully charged while running. The jump starting is a good clue. I don't know much about it yet, but there is a current sensor on the negative battery cable. Maybe look into that (not sure if you replaced that sensor also). I've read that it controls how much alternator output is supplied to the battery based on demand. My thought is maybe a bad connection there or dead rectifiers in the sensor. Just FYI I have also read that there shouldn't be any accessories grounded directly to the battery or the negative cable between the bat and sensor because the sensor, PCM and ECU wouldn't detect the extra load, hence not increasing alternator output that is needed for the demand. I've gotten lucky in the past where the battery wasn't fully charging becuase of a slipping belt (easy fix). I could be full of boogers as I'm just learning this system but that's my basic take on it. Wish I could help more and I hope it works out.

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smj999smj
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Postby smj999smj » Tue Apr 16, 2019 3:35 am

ssobol wrote:FWIW, when my Pathfinder is off (key out of the ignition all doors closed) I measure a current drain on the battery of about .25A. I know that this is some drain on the battery normally in this condition, but is .25A higher than normal?

Thanks.
BTW, are you sure it's ".25A" and not ".025A?" If it is .25 amps, then you have a hell of a draw! For parasitic loss, you don't want to see more than 50-milliamps, which is .050A.

ssobol
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Location: No. VA

Postby ssobol » Tue Apr 16, 2019 10:54 am

smj999smj wrote:...

BTW, are you sure it's ".25A" and not ".025A?" If it is .25 amps, then you have a hell of a draw! For parasitic loss, you don't want to see more than 50-milliamps, which is .050A.
Turns out that the current draw is about .25A for some minutes after the vehicle is switched off. After awhile it drops down to about .05A. If the electronics backup fuses are removed, the current drops right away when the vehicle is switched off. I read somewhere that it can take 20-30 minutes for modern vehicles to fully power down after switching them off.

Ended up replacing the Interstate battery that came in the truck with a Walmart EverStart Maxx. So far things are working fine.

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Bdaniel4
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Postby Bdaniel4 » Tue Apr 16, 2019 6:35 pm

I am having the exact same problem. When its the least bit cold, it'll crank and turn over fine, just won't start. Hook it up to jumper cables and it fires right up. Once it starts and runs, it'll be good for the day.

Recently, however, I pulled up to a stop sign and the truck just died. Fuel pump not coming on when the ignition key is turned, obviously still cranks just fine. Had to have it towed to the shop and the thing fired right up as soon as it got there, I guess after bouncing around on the tow truck. The shop kept it a few days to try to diagnose, but everything they tested was fine. No current draw or anything.

Of course, the next day it stalls on me at a red light. Towed back to shop. They checked just about everything they could, mechanically. Still no draw, cam sensor was good but found no injector pulse and pretty much no communication. Having it towed to an electronic specialty shop tomorrow, but my mechanic's diagnosis was the computer failed.

I'll update when I get more info.

Andyzeg
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Postby Andyzeg » Wed May 01, 2019 3:24 am

Please see my new post regarding "Battery Drain - seems a common issue" as it seems that the ECM relay may well be the culprit to the engine cranking issues folks are having....as well as battery drain due to the same relay going bad.

I hope this helps?


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