Starter won't crank with ignition key sometimes...

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songzunhuang
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Starter won't crank with ignition key sometimes...

Post by songzunhuang »

My car recently began to exhibit something that's got me stumped. Sometimes when I put the key into the ignition and turn, the starter will crank the motor and the car will start normally. Every once in a while, I'll turn the key and nothing will happen. The starter doesn't crank.

When this happens, I can leave the key turned to the "on" position and then use the diagnostic port to turn the starter. I jump pins 11 & 14 and the motor will crank and the engine will start. It runs normally after I manually crank it up using this trick. After I drive home, sometimes I turn the car off and then try to start it normally and it works! Other times it won't. It's go me confused.

I have an automatic 4 speed transmission. It was postulated that maybe the relay under the driver side dash was faulty. I replaced that relay and things seemed to work for a while, but now I am having intermittent issues again. I've not been able to spot much of a pattern yet. Although it I have noticed that the car almost always cranks and starts in the morning when it's cool. The past few days when it was quite warm (85-90 degrees), the car's starter won't crank after it's been sitting in the parking lot at the end of the day.

Does anyone have any idea of what else I can try? Any help would be much appreciated.
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Song Huang
1984 633CSi
Last 7 of VIN: 6997383
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Re: Starter won't crank with ignition key sometimes...

Post by songzunhuang »

Verified that temp has something to do with it. Worked on car yesterday. Inthe morning it cranked right up. Drive it into position in driveway to tinker. In afternoon, tried to move it back. It was hot. No starter crank. I listen carefully and there was no relay "clunk" under the dash. Something is preventing the relay from energizing.

I once had a intermittent contact issue (speedometer) that was finally resolved by reflowing solder joint. I currently have a wonky fuel gauge that I suspect may be related to a solder joint.

Does the starter circuit run through the instrument cluster for anything? I am wondering if a solder joint may be enough to cause this. Just a guess.
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Song Huang
1984 633CSi
Last 7 of VIN: 6997383
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Brucey
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Re: Starter won't crank with ignition key sometimes...

Post by Brucey »

on manual gearbox cars I'd say to look at the ignition switch, for sure. It is still worth a look with an autobox car but this failure is much less common on these.

Otherwise it is just a question of examining everything carefully in the relevant circuit using a multimeter to see what is live when it should be. Remember that the starter relay (only in autobox cars) is also inhibited by the gearshift lever, which has a switch in the base. Very often this arrangement is full of dried grease and fluff and it surprises me that it doesn't fail more often. There is also a molex-style harness connector near the gear shifter that needs to work perfectly too.

If you have/have had an immobiliser on the car that could also intercept the starter circuit too.

cheers
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Re: Starter won't crank with ignition key sometimes...

Post by tschultz »

viewtopic.php?f=25&t=25858&p=204911#p204911

This was my problem recently also.
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Re: Starter won't crank with ignition key sometimes...

Post by TN_M6 »

On the times when it wouldn't start did you try N instead of P in case it's the gear range selector switch.
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Re: Starter won't crank with ignition key sometimes...

Post by songzunhuang »

TN_M6 wrote:On the times when it wouldn't start did you try N instead of P in case it's the gear range selector switch.
Yes, I did try that several times. It didn't seem to make a difference so I'm not convinced that's the issue. However, when I get a chance I will get in there with a multi-meter and check it out. It should be daily easy to troubleshoot.

Thanks for the suggestion though.
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Song Huang
1984 633CSi
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Re: Starter won't crank with ignition key sometimes...

Post by songzunhuang »

Brucey wrote:on manual gearbox cars I'd say to look at the ignition switch, for sure. It is still worth a look with an autobox car but this failure is much less common on these.

Otherwise it is just a question of examining everything carefully in the relevant circuit using a multimeter to see what is live when it should be. Remember that the starter relay (only in autobox cars) is also inhibited by the gearshift lever, which has a switch in the base. Very often this arrangement is full of dried grease and fluff and it surprises me that it doesn't fail more often. There is also a molex-style harness connector near the gear shifter that needs to work perfectly too.

If you have/have had an immobiliser on the car that could also intercept the starter circuit too.

cheers
BTW - I initially purchased an ignition switch and paid $27 for overnight shipping! Then I thought the relay fixed it, so I returned the switch (eating the $27 shipping). Now I am not so sure again. I should have just replaced it just to eliminate the possibility.

In any case, when I get a chance I'll test the switch with a Multi-meter as well. I found a procedure somewhere and bookmarked it. I just need a few hours to tinker on this. Since I've got a workaround (diagnostic port pins 11 & 14), I have turned my attention back to the A/C repalcement again.
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1984 633CSi
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Ralph in Socal
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Re: Starter won't crank with ignition key sometimes...

Post by Ralph in Socal »

Check the connector block on the side of the steering column. The starter trigger wire is black and connects separately to the connector block. Check the fit of that wire into the connector. If it's a little loose pinch the rear end of the female connector so that you get better contact when completely inserted. Spray the connector block with contact cleaner.

Ralph
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Re: Starter won't crank with ignition key sometimes...

Post by songzunhuang »

Ralph in Socal wrote:Check the connector block on the side of the steering column. The starter trigger wire is black and connects separately to the connector block. Check the fit of that wire into the connector. If it's a little loose pinch the rear end of the female connector so that you get better contact when completely inserted. Spray the connector block with contact cleaner.

Ralph

Thanks Ralph. Any hope of a picture? I did fiddle in that area but I was in a hurry and just generally wiggled all the wires to make sure nothing was obviously loose. I'll get back to this again soon. Since I have a workaround I've just lived with it.

Currently looking at AC issues, but am now sidetracked by a slow oil leak. Wife can't stand spots on the driveway.
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Ralph in Socal
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Re: Starter won't crank with ignition key sometimes...

Post by Ralph in Socal »

This is what I have right now but the connector is on the side of the steering column after you remove the lower dash cover. You can see on the connector how the Black Wire is on the end of the plug and has a separator. A single Black Wire, with a female connector, plugs into that slot with the male connector.

The trick with the female connector is to just slightly pinch down on the rear end of the metal tangs that mate with the male connector so that you have tight contact when fully inserted. Of course the metal connector has to be removed from the plastic housing to perform this pinch. Best way I can describe it but I'll see about a photo in a bit. Tasks at hand right now.

Ralph
Ignition Switch.JPG
Ignition Switch.JPG (259.61 KiB) Viewed 5255 times
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
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