84 300cd intermittent starting

[billdarling]

I recently have had some starting problems with my 84 300cd:

The first time it happened, the car wouldn't turn over at all after a fill-up--had it towed, replaced the ignition switch, all seemed to be fine for a few weeks (10-20 starts).

The second time it happened, i drove it for a long distance (200 miles), arrived, and then proceeded to try to start the car again to run an errand--no turn over. I had the starter replaced with a rebuilt bosch unit, and everything was fine for about 5 days (again, 10-20 starts).

The third time happened i drove back the same distance (another 200 miles), parked, and i tried to start the car again away--no turn over.

However, 2 hours later the car started, no problem.

Now, when i use the car, it fails to turn over about every 5 start attempts--mostly after I've driven it somewhere. But, if I leave it sit and come back to it (10-15 minutes), it starts strong, no problems. The first two times i had problems, there was no way to get the car to turn over at all, hence, the replaced parts.

I'm pretty sure it's not the neutral safety switch--i've tried starting in every gear as well as moving the shifter while i try to start. Also, to my knowledge, there's no starter relay.

Is there something simple i'm looking over?

Any help would be greatly appreciated...

[leathermang]

I had the same kind of symptoms.....
I have posted the information and pictures in the archives..
It turned out to be the three screws inside the starter which hold the mechanism which holds the brushes.. they were loose ( I don't know why.... the car was only 25 years old at the time ) and arching...
The Alternator shop in a farming community which has been in business for 90 something years took my old one apart while I was standing there watching them...the evidence was clear... they had a rebuilt correct starter sitting there which had not been picked up.... $100 plus $8 tax and I did not have to drive back over there to pick up mine..... no more problems in that area....

[billdarling]

So, chances are, the rebuilt starter i got is bogus?

Definitely seems likely, but it doesn't seem like it would be the same exact thing you're describing (screws being loose), as it was freshly rebuilt, although i know that's no guarantee--you had an original starter?

also, could you point me in the right direction to your previous post(s) with photos? thanks for the reply

[barry123400]

I would be suspicious of everything in the starter circuit. Since it is so bad most of the time you should be able to find it fairly easily.
Rather than disturbing things get a voltmeter and start checking. I suggest getting a friend to hold the key in the start position and go from there. The worst thing would be to make it even less intermittent.
Initial tests I would do. With key in start position measure between negative terminal on the lead battery post to a clean metal point on the starter case. It is a rebuilt so it should be pretty clean. You should read no voltage. Then from centre of the positive lead post to the stud with the large cable on the starter. Again you should read nothing. Next from the centre of the negative terminal to the small wire terminal on the starter. Now you should read about 9-12 volts.
If you do all those tests with the key in the start position and record and post the results it will give a good indication of exactly where the problem is. Do not disturb too much either while doing it. It is much easier to find when the circuit is not functional. Your friend can keep the key in the start position for awhile without running the battery down during the tests I think. The danger of continually turning the key is that the starter may start to work. You do not want that to happen while getting your voltages. This may sound complicated but is really pretty straigtforward if you think about it. You could have gotten a bad starter it's possible. So are quite a few other things. It was quite a job to change the ignition switch and I have to wonder what led you there. A lot of people would just clean every connection in the circuit for starters. That might do it. I preffer to locate the exact cause first. Just my approach to this type of thing. It does not infer it is better or worse approach but just an approach. Before you start read the battery voltage from lead post to lead post. Without the key on it shopuld be about 12.5 volts. Read the voltage with the key on as well..If it remains at 12 or above just continue the mentioned tests. If it sags to 9-10 volts mention that on site before proceeding. You may not have enough battery voltage to energise the solinoid on the starter.

[leathermang]

Hit the search button on this page,
choose advanced search,
put word ' starter' into first box,
put 'leathermang' into second box ( poster )
it should give you 108 threads...
go to second page,
choose thread titled ' 240 odd behavior'
pictures are there..

[billdarling]

Originally Posted by barry123400

It was quite a job to change the ignition switch and I have to wonder what led you there.

I was stranded on the Jersey Turnpike, and at the mercy of a local mechanic, but according to him, he pinpointed the problem as the switch. And according to the bill, you're right, it was quite a job.

Thanks for your other suggestions--I will definitely give the voltage testing a shot--the trick will be, as you mentioned, that the starter not be working...

If the battery is failing, any chance the supplied voltage would dip lower at certain times (e.g., right after the car has been running--not logical, i know) so that i wouldn't get enough charge to energize the solenoid?

[barry123400]

One member mentioned a good look at the archives as well. Good ideal. Sometimes to gain comprehension of function I will draw out the circuit with all its components. Basically it's what works for you that counts. The mechanic that worked and changed the key switch out might make me suspect he did so because the voltage to energise the solinoid while troubleshooting was not there.. I suspect you are going to find the 9-12 volts missing at the solinoid on the small terminal with the key on and starter not energised.
In fact do that test first and forget the others for now since it is the most obvious thing to do allowing what the mechanic did.. Or thought was wrong. If the voltage is missing your first suspect is going to be an intermittent neutral switch on the transmission. I think there is a test that helps tell if it is bad or at least really localise the problem to some further extent. If you short two terminals in a little black box on the inner fender it bypasses that switch and it's associated wiring and terminations I believe but not sure. Again just check the archives as the test is well described there. I now hope you are going to find it reasonably fast.
I find it a little hard that he missed the cause but it may have been very intermittent when he was testing. Intermittent conditions can easily fool people. I just know he would have not been at the key switch if the trigger voltage to the solinoid was present. Unless he loved to suffer or really ripped you off. I also suspect he would have fixed the original problem as well prior to changing the switch if he was doing you. I guess that makes me a born cynic.

[billdarling]

To clarify--the first two times this happened it would not start at all--and still wouldn't many hours/days later--dead, nothing.

Now when i come back in ten minutes the car starts again after failing just before. I find it hard to believe that all along it was the neutral safety switch being flaky, or maybe i just don't want to believe it after giving up so much cash to mechanics in the past month. Not saying that it may not be the problem now, but i'd hope that at least one of my investments (ignition switch & starter) was worthwhile.

The tests you're descibing sound like a great place to start--i'll get on it as soon as i can--

now's the time when you need a garage, i'm in an apartment and park on the street, so it's hard (and cold) to do work on the car after dark...

[billdarling]

latest news on my starting problem:

I finally had a chance to take the car to my regular, trusted mechanic.

-He's ruled out the starter & starter solenoid--tested both

-He's ruled out neutral safety switch

-Battery is strong

-Glow plug relay is good

-He doesn't think it's ignition switch

He's been having trouble getting the car to not start, actually.

I gave him some tips (ha)--

The problem occurs after I have been driving for more than 10 minutes or so--seems that the longer I drive, the more likely the problem is to occur. Quite simply I turn the car off, and try to start it again and it doesn't turn over--I hear a click (maybe the ignition switch?), and that's it. If i leave it for about 10-30 minutes it will start.

Sorry if i'm repeating myself in this post, but wanted to save time for someone new to it who wants to post a reply.

suggestions, please....

[toomany MBZ]

Sounds like maybe a heat induced expansion somewhere. No fun taking readings on a hot starter, if you are able to test all those things you've already had tested, when in a no start condition, you might be able to localize problem. Good luck.

[billdarling]

Originally Posted by toomany MBZ

Sounds like maybe a heat induced expansion somewhere. No fun taking readings on a hot starter, if you are able to test all those things you've already had tested, when in a no start condition, you might be able to localize problem. Good luck.

yeah, that's the trick--car not cooperating at mechanics when i need it to NOT start (again, ha!)

A Heat induced expansion--meaning--in the starter?

However, I've also experienced the problem when the car was (relatively) cold.

[toomany MBZ]

Glad you have a healthy sense of humor. The expansion could be anywhere there is a metal conection where there are different masses, one will expand at a different rate. However, if your having a problem at "low" temps.......well. Is it possible the starter has a bad spot that cannot be detected unless it's on said spot? Dunno, maybe someone else can help with that. Keep plugging.

Sounds like it could very well be the solenoid. I know that you say that the tech ruled it out, but I'm not sure how he did that.

The next time it fails to start, use the blunt end of your lug wrench to momentarily short between the nut that makes the electrical connection into the starter motor itself, to the nut just above it on the solenoid. This will bypass the solenoid and spin the starter motor itself. Then try to start it with the key. It could take a time or two, but if after spinning the motor just a little the car starts with the key, then you need a starter or possibly replacing the solenoid itself will fix the problem. There is an eccentric adjustment at the starter solenoid that may have to be experimented with when replacing the solenoid.

If you need a starter, not ALL Bosch remanufactured units are done well. Buy one from Steve Brotherton at Continental Imports in Gainesville, Florida and you will know that you are getting a good unit.

Good luck,

[billdarling]

Originally Posted by LarryBible

If you need a starter, not ALL Bosch remanufactured units are done well.

Well, it was the starter.

The Bosch replacment that was put in previously--to quote my mechanic--"looked like it was rebuilt in someone's backyard"

So, heed LarryBible's advice and be choosy who you get your unit from if/when the time comes.

He put another rebuilt Bosch unit in, from a trusted source, and it starts like a dream now--every time.

Thanks to everyone who posted their thoughts--definitely helped.

Hopefully someone will learn from this post & save themselves some money &/or time.

thanks!!!