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intermittent no start problems 87 4.0 auto


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Hey all

 best wishes for the new year! I have encountered a problem that i hope the collective wisdom of the forum can help me with. My 87 2wd auto  occasionally won't start as of late. All the instruments etc in the cab have power, there is just no cranking of the motor -regardless if its park or if i switch to neutral. I have replaced all the power cables, and done the ground refreshing etc along with replacing the ignition switch that's  down in the column (my turn signal relay went out so i replaced them both at the same time)  . If i wait for a bit  it always starts up again, but i'm fearful it will take a dump on me in some remote location and won't start.  Should i be looking a some replay perhaps ? or other suggestions ?

 

thx as always!

 Mike

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Hi Cruiser 

  i don't have  accurate numbers,  but there is a large drop from 12.5V  on my dash board  volt reader even if the truck starts - the non starts occurs so infrequently i haven't  checked that out yet as it always catches me by surprise  and like i said it seems to start 2-3 mins after the non start condition (at least to date it has)

 

m

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Try switching quickly back and forth from park to neutral next time it happens. Sounds like a neutral safety switch issue to me. Mine started out infrequent and usually would start if I stuck it in neutral but sometimes wouldn't, getting worse and worse until I was having to short the solenoid to get it to start two out of three times.

It wouldn't hurt to clean out the NSS anyhow. If it's never been done it could probably use it anyhow. http://bc4x4.com/tech/2010/jeep-neutral-safety-switch-nss/. I ran a bead of silicon around mine before putting it back together to try to keep grime out a bit longer.

Could also be the rod between the ignition cylinder and the switch is out of adjustment and sometimes doesn't quite make contact. But my money's on the NSS.

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And do what with them? 

 

 

well, i don`t know, drop the starter, wire it to a good battery and make sure it turns as it should, he says the ignition switch is new but is it really working? mine has to be turned and pushed really hard sometimes to make good contact, he has an auto tranny, is the neutral switch really working?

 

 

the problems seems very straight forward to me...

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And do what with them? 

 

 

well, i don`t know, drop the starter, wire it to a good battery and make sure it turns as it should, he says the ignition switch is new but is it really working? mine has to be turned and pushed really hard sometimes to make good contact, he has an auto tranny, is the neutral switch really working?

 

 

the problems seems very straight forward to me...

 

But, it's intermittent. That's why he needs to narrow it down by watching the voltmeter.........

 

If he pulls the starter and it spins, what does that tell him? It's spinning now, but wait, it does that most of the time. 

 

The test above will also help pinpoint a bad NSS.

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OK thx guys - i'll watch the volts and play around - going between neutral and park didn't seem to make any difference - problem is its done it once in the last 3 weeks - prior to changing out the ignition switch it was doing it about once a week so i thought i had nailed it down but apparently not, i do believe the starter is original - i'm also trying to remember if i hear the fuel pump spinning up when there is a non start but can't recall - i'll pay more attention and start compiling a list addressing the suggestions the next time it occurs

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hey Gang

So i replaced the starter, not sure if that was it or not but i had a $40 discount from Napa so figured why not, ended costing me about $33  - the new starter sounds different than the old one for what ever that worth.  The non start hasn't occurred, so maybe that it - but i'm going to pull the NSS and clean it up - can you guys tell me will the one on my jeep (2wd) be similar to the one described in this link http://bc4x4.com/tec...ety-switch-nss/. ? 

 

thanks as always!

mike

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New fresh starter motors always sound different since the bearings and solenoid linkage are well, new and tight. They also usually crank a lot faster than the one it replaced because the mains connections are cleaner with less resistance.

 

And all Jeep AW4 NSS's are the same.

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  • 2 weeks later...

Had the same problem last year.  Went to an old guy, even older than me, who has had an auto electric business since Thomas Edison.  First thing he asked me was where the starter is located.  I looked at him, wondering what he was up to, and told him.  He then asked if I knew what was right above it, and I told him it was the oil filter.  He then finally explained that when people still had their starters rebuilt, he got a lot of 4.0 starters in because they ended up with oil inside the housing that eventually shorts the armature.  Let it sit for awhile, the oil drains down and often it will start until next time.  I put a new starter in, and it's been great ever since.  Took the old one apart before I took it back for core, and sure enough it had about a tablespoon of oil in it and was generally a mess.   

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