Starter Solenoid not always working

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GT08
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Car Model: MK2 Jetta CSX
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Starter Solenoid not always working

Post by GT08 » Fri Jul 13, 2018 8:17 am

Hi,

I am having trouble with my Mk2 Jetta and starting.

The starter spins freely but the solenoid does not always kick in when cold. When warm it works most of the times.

This is not the same as a flat battery where it just clicks. The Starter spins freely and fast, just without the solenoid kicking in.

I have not tested the battery for holding amps, will do so tomorrow. I have checked the voltage during cranking and it falls to 12.2v during cranking starting at 12.9 v before.

I am asking now as there has been some strange things happening when starting.

So I have taken the starter apart and inspected and cleaned it thoroughly. All seemed in order, the brushes have about 5-6mm left, the wingdings have no arcing on them. The solenoid shaft is clean and not pitted.

So to the strange things. This has been ongoing for a week now, but this morning, it goes like this.

In Neutral, clutch in, Try Start just spins (this is how I normally start the car every day). First gear, clutch in, just spins. Neutral no clutch, just spins. Out of frustration I put it in third gear, clutch in starts first time no issues.

This happened a few days ago as well, but with first gear. If it was the throw out bearing, it would be better to start in neutral with no clutch so the in gear thing is either a BIG coincidence or points to something sinister like the bearings in the bell housing.

Any idea what to check first (after checking the battery)?
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1992 Jetta MK2 CSX 2.0l ADY
2.0L 8v ADY, OEM G-Cam
Perfect Power XMS 5B-8A
70wkw 144nm
4-in-1 Cowely Branches, PowerFlow 63mm Stainless Steel FF, 76mm X-Force Stainless Steel Exhuast Tip
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Re: Starter Solenoid not always working

Post by panic-mechanic » Fri Jul 13, 2018 9:12 am

The motor will only spin if the solenoid has moved forward. That movement completes the circuit for the motor to run otherwise it will always bang the gears into the flywheel.
So whay I ma saying is that it is your bendix that is stuffed. If the motor runs but it does not turn the engine the bendix ratchet is slipping. The fact that it eventually worked was just that it was coincidence and thatbitnhad warmed up or accidentally grabbed that time.
Get new bendix. It will be sorted.
Stephan van Tonder - Jhb - Putfontein Benoni
'07 Audi S6 V10 - beast !!!!!
'05 Audi A6 3.0L TDI Avant
'09 Audi Q5 3l tdi
'95 Audi 90 coupe quattro
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Re: Starter Solenoid not always working

Post by grease monkey » Fri Jul 13, 2018 9:23 am

Try putting the car in neutral, (very important) leave the ignition on and bridge from battery supply to the solenoid supply. If you do it a few times and the starter works properly - you have a voltage drop from the ignition to the starter solenoid in which case , fit a relay on the solenoid to get power direct from the battery,Bendix is also a strong possibility Check your earth cable from the battery , it could have resistance- remember it an old car. If you don't have any joy , when the starter starts its slipping , leave everything as is and pull the starter and check the ring gear(try to avoid the engine turning so you see the correct point on the ring gear
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GT08
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Re: Starter Solenoid not always working

Post by GT08 » Fri Jul 13, 2018 1:19 pm

panic-mechanic wrote:
Fri Jul 13, 2018 9:12 am
The motor will only spin if the solenoid has moved forward. That movement completes the circuit for the motor to run otherwise it will always bang the gears into the flywheel.
So whay I ma saying is that it is your bendix that is stuffed. If the motor runs but it does not turn the engine the bendix ratchet is slipping. The fact that it eventually worked was just that it was coincidence and thatbitnhad warmed up or accidentally grabbed that time.
Get new bendix. It will be sorted.
When bench testing the starter the bending did engage, but that is obviously without the load of the engine. I have read online that the small bearing in the bell housing can wear and cause the Bendix to not full engage because of misalignment.

The starter is quite new (like 4 years old), will takeout the starter and test the bendix, maybe even take it apart to see how the thread insidle looks.
Thanks for the reply.
grease monkey wrote:
Fri Jul 13, 2018 9:23 am
Try putting the car in neutral, (very important) leave the ignition on and bridge from battery supply to the solenoid supply. If you do it a few times and the starter works properly - you have a voltage drop from the ignition to the starter solenoid in which case , fit a relay on the solenoid to get power direct from the battery,Bendix is also a strong possibility Check your earth cable from the battery , it could have resistance- remember it an old car. If you don't have any joy , when the starter starts its slipping , leave everything as is and pull the starter and check the ring gear(try to avoid the engine turning so you see the correct point on the ring gear
I have always read up on the relay, but being not that electrically inclined I have stayed away from that. Will look into it some more, so many threads say to do this. I have to admit the pos cable is currently an issue for me. It is a 0 gauge sound wire that I made up myself. It works but does not give me much confidence, will replace with correct and proper battery pos cable.

The ring gear did not have visible damage, but did have a lot of clutch dust on it, some even on the teeth.

Thanks for the reply.
Image
1992 Jetta MK2 CSX 2.0l ADY
2.0L 8v ADY, OEM G-Cam
Perfect Power XMS 5B-8A
70wkw 144nm
4-in-1 Cowely Branches, PowerFlow 63mm Stainless Steel FF, 76mm X-Force Stainless Steel Exhuast Tip
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Re: Starter Solenoid not always working

Post by grease monkey » Fri Jul 13, 2018 5:15 pm

A relay is pretty easy and isn't intrusive on your harness. All you need is a 5 pin 12volt relay(30 amp)
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Re: Starter Solenoid not always working

Post by panic-mechanic » Sat Jul 14, 2018 7:20 pm

if the solenoid is kicking in and he motor is turning then the relay ain't the answer. But go ahead. Eventually they need it anyway.
Stephan van Tonder - Jhb - Putfontein Benoni
'07 Audi S6 V10 - beast !!!!!
'05 Audi A6 3.0L TDI Avant
'09 Audi Q5 3l tdi
'95 Audi 90 coupe quattro
'13 VW CC 2l tdi (repair project)
'05 Touareg v10

Perfect Power dealer. I do dyno tuning.
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GT08
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Re: Starter Solenoid not always working

Post by GT08 » Mon Jul 16, 2018 12:56 pm

I will post pics tonight, it starter first time this morning. So far it seems to have been the bendix.

I have replaced it and now it seems to work. The old bendix had a blue tint on the bottom from the heat.
I assume the solenoid wanted it to move and when it did not, the starter spinning caused it to heat up a lot.

With this I replaced the thrust bearing (throw out bearing?) and the push rod to eliminate the clutch sticking during startup.
The push rod had a small flat tip on the gearbox side. Was probably about 0.8mm to 1mm shorter.

Will see tomorrow morning in the cold if it starts without issues.
Image
1992 Jetta MK2 CSX 2.0l ADY
2.0L 8v ADY, OEM G-Cam
Perfect Power XMS 5B-8A
70wkw 144nm
4-in-1 Cowely Branches, PowerFlow 63mm Stainless Steel FF, 76mm X-Force Stainless Steel Exhuast Tip
VAG Fan
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Re: Starter Solenoid not always working

Post by VAG Fan » Tue Jul 17, 2018 12:16 pm

Do you perhaps have a part number for your starter (or engine code for your Jetta), and specifically a part number for the corresponding bendix / ratchet? I also need to replace the bendix on my HM's starter, and wanted to cross-check the part numbers, if the starters are the same.
Mark R.
- - - - - - - - - -
1992 Audi 500 SE, type C4, AAR, 335k (2001-current)
1990 VW Fox, type 16, HM, 245k (2005-current)
2004 VW Golf, type 1J, AHF, 231k (2016-current)
Previous:
1978 Audi 100 GLS 5E, type 43, WC (1991-92)
1983 VW Golf GTS, type 17, FR (1992-2005 but still in the family)
- - - - - - - - - -
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GT08
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Re: Starter Solenoid not always working

Post by GT08 » Tue Jul 17, 2018 6:05 pm

It works now after replacing the Bendix. Thanks for the Advice.

So to the pictures I mentioned of the old Bendix:

Image

Image

Image
VAG Fan wrote:
Tue Jul 17, 2018 12:16 pm
Do you perhaps have a part number for your starter (or engine code for your Jetta), and specifically a part number for the corresponding bendix / ratchet? I also need to replace the bendix on my HM's starter, and wanted to cross-check the part numbers, if the starters are the same.
I orignially had the HV 1800 8v carb engine. The part numbers as follow:

New starter GW Part # A1127, Orignal Part #:

Image

Bendix GW Part # A3105 Orignal Part #:

Image

I hope this helps.
Image
1992 Jetta MK2 CSX 2.0l ADY
2.0L 8v ADY, OEM G-Cam
Perfect Power XMS 5B-8A
70wkw 144nm
4-in-1 Cowely Branches, PowerFlow 63mm Stainless Steel FF, 76mm X-Force Stainless Steel Exhuast Tip
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Re: Starter Solenoid not always working

Post by VAG Fan » Wed Jul 18, 2018 10:51 am

Yes, this helps indeed, as both engines appear to use the same 1.1 kW starter. Thank you very much for the info and good pictures.

My search had tentatively led me to exactly the same Bosch part number for the replacement bendix, and I've already mailed my contact at Diesel Electric North (Bosch) for a quote. Your cross-reference to the GW number (A3105) was the last missing link, so I'll also give my local GW a call.

The blue discolouration is quite impressive...

[Edit: GW doesn't find the Bendix as a separate part if you ask them for it as such. They say they only keep the whole starter. But when one quotes the A3105 number, they do have it. And the price is very good, too: R171 (genuine Bosch part).]
Mark R.
- - - - - - - - - -
1992 Audi 500 SE, type C4, AAR, 335k (2001-current)
1990 VW Fox, type 16, HM, 245k (2005-current)
2004 VW Golf, type 1J, AHF, 231k (2016-current)
Previous:
1978 Audi 100 GLS 5E, type 43, WC (1991-92)
1983 VW Golf GTS, type 17, FR (1992-2005 but still in the family)
- - - - - - - - - -
User avatar
panic-mechanic
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Re: Starter Solenoid not always working

Post by panic-mechanic » Wed Jul 18, 2018 8:07 pm

plain laziness on the sparesman's part. They also get comission so if he sells you the starter he gets more money at the end of the month
Stephan van Tonder - Jhb - Putfontein Benoni
'07 Audi S6 V10 - beast !!!!!
'05 Audi A6 3.0L TDI Avant
'09 Audi Q5 3l tdi
'95 Audi 90 coupe quattro
'13 VW CC 2l tdi (repair project)
'05 Touareg v10

Perfect Power dealer. I do dyno tuning.
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