Fuel Shut off solenoid issue(n109)

claytski

Veteran Member
Joined
Jul 19, 2007
Location
jefferson, nh
TDI
98 jetta tdi
just rebuilt a ahu. motor was toast, bought it like that, rebuilt it, and now its running. I couldn't get it running. I cranked it over with no fire. I hooked up the vag com and the only thing I pulled up was the fuel shut off solenoid, open or short to ground(n109). I checked the 109 relay and it seems to work. the glow plugs seem to be hooked up to this relay and without it, they don't work. with it, the glow plug light comes on, and stays on. The fuel shut off solenoid however does not. I took a positive wire from the battery and grounded out the solenoid. it will fire up if I do this. I have read that the needle lift valve wiring may have something to do with this? I had the original #3 injector worked on and I got a different one back. mine was so bad that frank worked me into a different one with a different plug. I have it jerry rigged to work with my harness. I have a blue wire and a grey wire from the harness. on the plug, there is positive and negative labeled. I have negative hooked up to the grey, and positive up to the blue. does that sound right? I pulled the 109 relay out and I tested it. it works fine it seems. any help on this would be great. now the time for the breakin.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
The fuel shut-off solenoid is electro-mechanical, not "electronic" per se. That is, the fuel shut off solenoid is a separate, stand-alone item that is either active (on, allowing fuel), or not. The #3 injector lift sensor is far more 'electronic' in that it is sending changing values back to the ECU where the ECU logic uses the data to control amounts of fueling, and even at that, the #3 lift sensor is a back-up to the main fuel metering system.
The fuel shut-off solenoid should be powered (on, allowing fuel) anytime the ignition is switched to the ON position, even if the engine isn't cranking or running on its own. These are times when there is zero lift to be sensed by the #3 lift sensor.
Summary: I think the two are completely separate issues.
 

AccountingTroll

Veteran Member
Joined
Dec 23, 2004
Location
PA
TDI
Passat, 1996, Pearl White 2006 NB, Red
claytski said:
I took a positive wire from the battery and grounded out the solenoid. it will fire up if I do this. .
This makes me think you have a short in the wire leading to the N109. Trace the wire.
 

98JettaTDI

Veteran Member
Joined
Dec 5, 2000
Location
Elyria, OH
TDI
1998 Jetta
Or trace the wire from the solenoid, I had mine break under the protective plastic covering for the harness. One butt-splice later and I was up and running.
 

claytski

Veteran Member
Joined
Jul 19, 2007
Location
jefferson, nh
TDI
98 jetta tdi
I had to splice in the harness. then, I went to the big connector with the 16 pins in it and tested. on the harness side I get .62 volts. I know the relay is good on it cause its new and it didn't change from one relay to the other. I would consider the fuse is blown but if the fuse was blown, it wouldn't put out voltage at all. anyone have any ideas?
 

Scott58

Veteran Member
Joined
Nov 26, 2006
Location
Enterprise, MS
TDI
96 Passat, 01 Golf
Sounds like you need to ohm out the individual wires to the fuel shutoff relay to their power source. Since you spliced the harness, I'd check for a crossed wire or a splice crimped to the insulation rather than the wire. Also check the fuse for input and output voltage. Since the engine was removed, make sure all the grounds were reinstalled. A missing or bad ground can cause these kinds of problems. Good luck.
 

claytski

Veteran Member
Joined
Jul 19, 2007
Location
jefferson, nh
TDI
98 jetta tdi
I only reconnected the wire that was cut. no other wires so the wire isn't crossed and the wire has continuity from the solenoid to the large multi connector.
 

claytski

Veteran Member
Joined
Jul 19, 2007
Location
jefferson, nh
TDI
98 jetta tdi
is there anyone out there that can help me trace out the fuel shut off solenoid circuit? I know relay 109 is good and new, and at the solenoid I get 0.67v. traced it back to the large multi connector. the wire is good from the connector to the solenoid. on the harness end of the connector, I still get 0.67v. From there it goes into the main engine harness and goes threw the firewall. anyone have any expirience with this?

also, pulled all the grounds off, cleaned them and put the dielectric grease to it.
 

jollyGreenGiant

Veteran Member
Joined
Feb 3, 2003
Location
MA
TDI
03 Golf TDI GLS ( my 5th TDI ), 03 Eurovan GLS - VR6 :(
This is exactly why you should buy a Bentley manual for your car...

Pin #53 on the ECM connector sends voltage directly to the N109 solenoid through two connectors, the 24 pin round one at the cylinder head and the 3 pin one down by the oil filter/ IP area, in a properly functioning circuit you should put one lead of your multimeter ( reading resistance ) on pin 53 of the ecm and the other on the disconnected end of the wire on the N109 and see .3 ohms +- ( .5 or so ohms ), if not, you've got a problem with the wiring, if you do, look elsewhere like inside the ECM for bad solder or a burned area.

Nothing on this circuit goes through the firewall into the car, this particular part of the harness goes up and across the back of the engine compartment over to the AC switches by the interior HVAC air filter, goes through a sheetmetal divider and then up onto the wiper "shelf" where the ECM is mounted.
 

jollyGreenGiant

Veteran Member
Joined
Feb 3, 2003
Location
MA
TDI
03 Golf TDI GLS ( my 5th TDI ), 03 Eurovan GLS - VR6 :(
DPM said:
...and relay 109 isn't directly connected to N109...
It's indirectly connected, Relay 109 powers the ECM, the ECM powers the N109 shut off valve...
 

claytski

Veteran Member
Joined
Jul 19, 2007
Location
jefferson, nh
TDI
98 jetta tdi
ok, I have the bently. I buy bently's for everything I own. I am not the greatest at reading and diagnosis on wiring. I did ohm it and there is nothing. so I guess the wire is toast.
 

jollyGreenGiant

Veteran Member
Joined
Feb 3, 2003
Location
MA
TDI
03 Golf TDI GLS ( my 5th TDI ), 03 Eurovan GLS - VR6 :(
There's two connectors in between the ECM and the N109 solenoid ( not including the ECM connector ), the 24 pin round guy and the 3 pin rectangle down by the fuel pump and top of the oil filter housing.

Common problem is the 3 wires ( for the pump timing solenoid and the N109 travel into a plastic harness sheath, the three wires bounce around a lot in there and develop wear on the insulation and eventually corrode, short, and open. The proper way to repair it would be to run new VW repair wires from the 24 pin to the 3 pin, it would be a bit of work, you may be able to just pull the harness apart, find the damage and repair it with solder or butt connector.

Let us know what you find. BTW: On A4 TDI's, the intake shutoff flap solenoid suffers similar problems I've found, the wires to that are in the same type of corrugate plastic sheeth that vibrates and wears the wire insulation...
 

digitol

Member
Joined
Sep 30, 2004
Hi, I've changed out my IP seals, and my vag com is giving me the same error. During the seal change, the nut that holds the wire harness to my fuel shut-off solenoid would not come off despite being turned (is there something broken inside there?), and resulted in the terminal breaking. I soldered the wire to the broken terminal, but the car won't start.

I was confused by "I took a positive wire from the battery and grounded out the solenoid. it will fire up if I do this. ."

Does this mean you connected a wire from the solenoid to the positive battery terminal, the negative terminal, or grounded it to the chasis? If I could try this it could eliminate some variables for me.

P.S. - yes I have a Bently if that helps things.
 

claytski

Veteran Member
Joined
Jul 19, 2007
Location
jefferson, nh
TDI
98 jetta tdi
take a wire from the positive terminal on the battery and just touch the wire on the solenoid. you will hear it click. all it needs is 12v.
 

digitol

Member
Joined
Sep 30, 2004
Awesome! Thanks so much. Sure enough, started right up. Problem pin-pointed. Update: Problem solved! Thanks for this forum & thanks to everyone who posts/contributes..I have learned so much. Hit me up if you need info on TDI: timing belt change,BioDiesel,injector pump seal changes mid and top level. I have 3 VW's in the family 95 supercharged jetta, 98 jetta TDI, and an 02 Beetle TDI. So I am quickly becomming familiar with these lovable buggers!
 
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blacksheep

Veteran Member
Joined
Apr 14, 2005
Location
Phoenix, AZ
TDI
2000 JETTA TDI GLS
digitol said:
Awesome! Thanks so much. Sure enough, started right up. Problem pin-pointed. Update: Problem solved! Thanks for this forum & thanks to everyone who posts/contributes..I have learned so much. Hit me up if you need info on TDI: timing belt change,BioDiesel,injector pump seal changes mid and top level. I have 3 VW's in the family 95 supercharged jetta, 98 jetta TDI, and an 02 Beetle TDI. So I am quickly becomming familiar with these lovable buggers!
I'm having issues with my fuel shut off valve too!

http://forums.tdiclub.com/showthread.php?t=265471

Any help besides ordering a new one with my last post in my link?
 

Shane47

Well-known member
Joined
May 5, 2013
Location
UK
TDI
Mk3 AAZ
As said check the resistance of the wiring from one end to another, will instantly tell you if its the valve or wiring playing up
 

MarsBar

Veteran Member
Joined
Apr 28, 2008
Location
San Jose, CA
TDI
B4V#2 "Flash", 2000 Jetta GL, B4V#1 "PaTuDI" (2008-2018 RIP)
Bump for an answer to Idleofwight's question.

B4V is stumbling & dying out at low speed/idle when turning right or straight (only done it twice turning left), and recently at highway speeds a few times. Can shut the key off and fire it right back up. Symptoms of a failing relay N109??????
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Could be. Relay 109 can cause momentary loss of function for the ecu and come right back. Can also leave you stranded. Perhaps happens more often when the inside of the car is warm?

Put in a new one and find out. Fairly inexpensive attempt.
 

bblume

Veteran Member
Joined
Jun 24, 2014
Location
Denver
TDI
92 Vw mk2 gtd
A bit of a NECRO bump here::::instead of starting a new thread I thought I'd try here.
I've got a couple different issues with my 1z swap into a mk2 and specifically a no start condition. I've gotten fuel thru the IP after Mitty vaccing and then when cracking injector lines to bleed air only a dribble of fuel comes out. After closing them all up and some continued cranking, no smoke and no start.

My n109 gets 12v (I'm using the mk2 battery { group 41 } but plan on snagging a new group 49) with key on. Then a click and it shuts off(voltage goes to nearly nothing). Or if I crank before the click eventually the voltage bounces around or drops to near zero)
Not sure what is telling the n109 to 'close'
I've got no n109 code
I've got continuity from pin 53 to the n109.
But vcds also shows an open or short to ground with n108 (could this affect n109?)
I've got continuity to pin 51 on the second wire (the middle wire going to n108) And I'm not sure how to test the third wire
I'd love to hear you're ideas!!!
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Normal for voltage to drop if you don't crank the engine. Should come back when you try to start.

Easy check is to remove the plunger from N109. Engine will still shut down when ECU sets the IQ to zero when you turn off the key.
 
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