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Author Topic: Motor won't turn over the whole way  (Read 3534 times)

October 10, 2020, 09:50:05 am

bvolks73

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Motor won't turn over the whole way
« on: October 10, 2020, 09:50:05 am »
I recently removed the TD motor from my brother's '90 Jetta to use in my '85 Jetta Coupe. The motor hasn't been started in a few years, but we had turned it over through the starter hole every once in a while (he had robbed the starter for his Golf), but never a full revolution. I finally got around to removing the stuck AC pump and other unnecessary "extras" yesterday, and it turns over normally most of the way, and then stops. If I turn it the other way, it seems to stop at the same point. Is there any way, besides pulling the injectors, that I can get some ATF into the cylinders?
Unfortunately, it feels to me like it might be a piston connecting with a valve stuck open.


1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #1October 10, 2020, 11:00:34 am

srgtlord

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Re: Motor won't turn over the whole way
« Reply #1 on: October 10, 2020, 11:00:34 am »
I had this problem on a used motor. When I pulled the head I found rust had built up on 2 of the cylinders. At this point throw a starter in the motor and see if you can get it to turn over
« Last Edit: October 10, 2020, 11:02:43 am by srgtlord »

Reply #2October 10, 2020, 04:35:03 pm

libbydiesel

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Re: Motor won't turn over the whole way
« Reply #2 on: October 10, 2020, 04:35:03 pm »
I do not think that it is good advice to try to start it with the starter motor.  If it is rust, then it is highly doubtful that it will run well even if the piston is able to grind over the rust.  More likely, if it is rust, you'll break a couple piston rings and need to pull it apart anyway.  If it is not rust, then using the starter could be an even more expensive and labor intensive choice.  The starter produces enough torque to bend the connecting rod if the piston cannot ascend properly.  IMO, it would be a better idea would to pull the head and have a look.

Reply #3October 10, 2020, 06:46:52 pm

bvolks73

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Re: Motor won't turn over the whole way
« Reply #3 on: October 10, 2020, 06:46:52 pm »
They dented the oil pan pretty good when they moved the car with a skid-steer. I don't know if it is bent enough to stop the motor from turning completely over. I'll drop the oil pan and see if that might be the problem.
1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #4October 10, 2020, 10:36:29 pm

ORCoaster

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Re: Motor won't turn over the whole way
« Reply #4 on: October 10, 2020, 10:36:29 pm »
At least that is an easy to do thing.   Pulling the head may be the next item if you can't get the engine to turn over with the oil pan off. 

Reply #5October 13, 2020, 02:57:13 pm

bvolks73

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Re: Motor won't turn over the whole way
« Reply #5 on: October 13, 2020, 02:57:13 pm »
Well, I decided to give it another try today. I listened carefully and I could hear that it was near the top of the motor, towards the fuel pump side, so I knew it wasn't the oil pan hitting. I kept gently working it back and forth and suddenly it went past the "bad" spot. I turned it over several times and then had the smart idea to remove the hose between the turbo and intake and sprayed some penetrating oil and put some ATF through the intake. I turned the motor over to get the mix sucked into the cylinders and it is stopping up again at a certain point. I assume it may be hydro-locked so I'll let it sit for a couple days and try it again.
1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #6October 13, 2020, 11:49:42 pm

ORCoaster

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Re: Motor won't turn over the whole way
« Reply #6 on: October 13, 2020, 11:49:42 pm »
If hydrolocked then pull an injector or a plug and push the fluid out.  Then try again. 

Reply #7October 14, 2020, 08:52:16 am

bvolks73

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Re: Motor won't turn over the whole way
« Reply #7 on: October 14, 2020, 08:52:16 am »
Plug?
1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #8October 14, 2020, 10:01:10 am

libbydiesel

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Re: Motor won't turn over the whole way
« Reply #8 on: October 14, 2020, 10:01:10 am »
Glow plug.

Reply #9October 14, 2020, 01:03:04 pm

bvolks73

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Re: Motor won't turn over the whole way
« Reply #9 on: October 14, 2020, 01:03:04 pm »
I feel so stupid. Lol. In my defense, I haven't driven or worked on a diesel in over 12 years.
« Last Edit: October 14, 2020, 01:27:34 pm by bvolks73 »
1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #10October 14, 2020, 10:47:45 pm

ORCoaster

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Re: Motor won't turn over the whole way
« Reply #10 on: October 14, 2020, 10:47:45 pm »
I should have elaborated.  My ownership of two of these things makes me do that.  Yeah, GP. 

Reply #11October 25, 2020, 10:24:53 am

bvolks73

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Re: Motor won't turn over the whole way
« Reply #11 on: October 25, 2020, 10:24:53 am »
I removed the 2 glow plugs that are easy to get at and it didn't help, so I poured some gas down the intake and let it sit for an hour or so to (hopefully) thin the ATF enough that it would flow past the piston and it worked. It turns over smoothly and evenly now. Hopefully I can get the oil pan changed and see if it is going to run some time this week.
1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #12October 26, 2020, 12:38:37 am

fatmobile

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Re: Motor won't turn over the whole way
« Reply #12 on: October 26, 2020, 12:38:37 am »
 Thanks for the update.
 Some progress.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #13July 17, 2021, 04:30:39 pm

bvolks73

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Re: Motor won't turn over the whole way
« Reply #13 on: July 17, 2021, 04:30:39 pm »
I finally got around to trying to start it yesterday and am having no luck. It feels like it has decent compression when it's cranking over, but all I got out of it was a couple kicks. I see some puffs of smoke out of the downpipe occasionally. I tried bleeding the injectors and am getting fuel to all of them. I am starting it off of a lawnmower gas tank under the hood because the fuel in the tank is 13 years old. It's around 28*C outside, so it should be warm enough for it to start easily. Any other ideas before I try a small shot of starting fluid?
1985 TD Jetta coupe
1995 Golf CL
1971 VW Doublecab
1999 Corolla
2005 Sx 2.0
2007 Yaris

Reply #14July 17, 2021, 07:39:12 pm

ORCoaster

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Re: Motor won't turn over the whole way
« Reply #14 on: July 17, 2021, 07:39:12 pm »
Do you know if the glow plugs are working or not?  You can check them for voltage and resistance in the block but to actually know they are getting red hot you need to pull them out of the block and apply voltage. 

I would do that over adding starting fluid.  That is just death to me on a diesel.  Especially one that has not been run in a while. 

The IP may also not be pumping fuel well either.  The vanes on the primary side have a habit of sticking and thus no real flow to the rest of the pump so you are short at the injector end.  Or your pressure is so low that the injectors don't pop open to deliver it.  No real good way to know on that.  If you pull the lines off the back of the pump and compare the amount of fuel coming out of each delivery valve you might see a difference.  But it is hard to know if it is under operating pressure.