98 Jetta cranks but won’t start

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Good morning everybody. Here’s my scenario. I have been driving my car without problems since I replaced the ignition switch.i bought the car with intermittent starting problems a year ago, replaced the ignition and have been enjoying the car since then. A couple weeks ago, I parked the car and the next morning it would not start. I have been fighting this for 2 weeks and can’t figure it out. I have read everything I could find,and this thread seemed the closest:
http://forums.tdiclub.com/showthread.php?t=491678&page=7
However, I still can’t get my car to start. I hot wired the fuel pump and it makes a humming sound, and I just replaced the 109 relay erroneously. When I crank the car, I get about 350rpm after about 1 second. I was going to crank and crack an injector line to confirm fuel. The more I read,the more confused I get. Am I heading in the right direction?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
one issue i have is not with the 109 its self, but the socket it sits in. Just a long shot here but try wiggling it when your starting! Its one tip that works for me that IS NOT in that thread.

So, are you getting 12 volts at the IP shutoff solenoid?
Can you give us a list of things you check out that you can confirm are good to go?
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Thanks, I will try that. Ok,here’s the list:
New ignition switch (about a year ago)
New 109 relay
Hot wire post on fuel pump (not sure if it’s the solenoid or the fuel pump)
Normal glow plug light
Reads rpms when cranking

Again, this instantaneously happened. It drove fine, and then one morning just didn’t start. Because of this, I suspect electrical, but don’t know enough about VWs to understand how the electrics are laid out. Engines need air,fuel,and not in this case,spark. Based on what I’ve read, my ECM is working?? The only thing I can figure is fuel.

When I wired the post on the pump, should it “click” or “hum?” I got a hum,so I was under the impression it is a pump. Based on what I can tell, I have the AHU engine. When I read, I am confused as to whether I have a fuel pump,or solenoid
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Well, hot wiring the fuel pick up won’t actually keep it from starting. The IP does all the work; the pickup is just to make things happy.
Unless you’re talking about the IP, if you are not getting 12 volts when the key is in the run position on the round solenoid screw on the top, then your 109 or a fuse or some other wiring issue is present, no need to hot wire. But if you have it wired to 12 volts and it’s still not starting, you can count that the 109 is working and it’s something else.
Did you crack the 3rd injector pipe? Is fuel spraying out? If so, you’re looking at some other issue.
What engine? I’m assuming by your sig it’s an AHU, these things only don’t start for a few reasons, TYPICALLY.
One thing many people look over is the grounds. I can tell you that if you’re missing or have a broken ground, it’s not going to start. There is a round wire harness connector next to the Trans side right next to the water glow plugs. If that is not grounded, the car will not start. Same with if the IP is not plugged in or a wire or some of the wires are broken going to that 12 pin connector.
Is your 3rd injector harness damaged?
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Maybe I am doing it wrong, but I get 0v on the post terminal on the end of the IP. I measured from it to ground. Is it supposed to have +12v when the key is on? When I was trying the other day, I ran a wire from the + battery post to that nut,but it didn’t help at all.

When I turn on the key, there is a quiet hum that stops when the glow plug light goes out. This is accompanied by a loud click of the glow plug relay kicking off. I haven’t been able to test the fuel yet,but I really think it isn’t getting fuel. It seems to me that figuring out the wiring to that post is the key

Is the IP it’s own lift pump? Is that stud terminal for fuel shutoff solenoid, and is it supposed to be energized with the key on?

Also,how do I insert a picture?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Maybe I am doing it wrong, but I get 0v on the post terminal on the end of the IP. I measured from it to ground. Is it supposed to have +12v when the key is on?
YES, that is correct, you want 12v to ground when the key is on run and starting. This opens the valve to let fuel into the IP. If it has 0v, it is Closed and no fuel can get into the IP. This is controlled by a few things buyt last in line is your 109 relay. The first in line is your ignition switch.

When I was trying the other day, I ran a wire from the + battery post to that nut,but it didn’t help at all.
When I turn on the key, there is a quiet hum that stops when the glow plug light goes out. This is accompanied by a loud click of the glow plug relay kicking off. I haven’t been able to test the fuel yet,but I really think it isn’t getting fuel. It seems to me that figuring out the wiring to that post is the key
Well if you gave that 12 volts, and you cant get it to start, it is 50/50 safe to say that this is not the only problem. This should be fixed as a #1 priority as you cant turn off the car if your hotwiring it unless you add a switch, its also controlled by the safety air bag deployment. If the air bag goes off its supposed to shut off power to the solenoid (I think) or its something else that is supposed to turn off the car if you get in a wreck or flip the car. (I think)
Fix this issue 1st. I had the same issue and i cant remember if jumping it was able to start. I have to wiggle my 109 now just to get it to start. Its not just for the solenoid, i think.
Is the IP it’s own lift pump? Is that stud terminal for fuel shutoff solenoid, and is it supposed to be energized with the key on?
Also,how do I insert a picture?
Either upload it someplace and copy the link or use the picture part of the forums. you have to keep the file size down, and most cameras dont do that by default. Do a search, its like a sticky on front page.
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Thanks for your replies. Tomorrow I will look ar the contacts for the 109 relay. It is new, and functions like the old one. I get normal lights and functions. Out of the relay,does power go to a fuse for the fuel cutoff solenoid, or straight from the relay?

When I hot wired it, I just put a wire from the battery to the stud. I thought that would at least let it run,but it didn’t.
 

ToddA1

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Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
If you have VCDS, scan the car. If your GP light and the rest of the idiot lights go through bulb check, the 109 is good.

-Todd
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
I don’t have a scanner, however, when I turn the key to run, I get check engine,oil,glow plugs. After 20? seconds, the glow plug light goes out and the car is ready to start. From the seat,everything looks like it always has.

I think it is just an issue of no fuel getting to the pump, but I am still not 100% on how it’s wired. Is there a schematic or line diagram?
 

JETaah

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Jan 18, 2001
Location
mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
Do you see fuel moving in the clear fuel line leading to the injection pump? Any bubbles in the line?

If it looks like fuel is moving without a TON of bubbles, try pulling the glow plugs and crank it a bit. If it is getting fuel into the cylinders you will see a mist of fuel coming from the glow plug holes. If you see a mist from all four holes, recheck the static timing.
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Before I go too far off track, I really think it’s electrical. The car worked flawlessly until one turn of the key. Is the stud in the picture supposed to have 12v with the key on?
 

KLXD

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Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Be aware that if you wait more than a second or two after turning the key on before checking the voltage on the C/O solenoid its power shuts off. It is powered back up if you crank it.

So either check it while cranking or immediately when you turn the key on.
 

Crusty

Active member
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Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Thanks everyone for your patience. I tested the stud as my kid turned on the key,and it read just under 12v. Then I cracked the injector line(17mm wrench) and cranked,but got no fuel


Also, I don’t see any clear line you guys are referencing.
 

Alchemist

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Joined
Nov 3, 2007
Location
Lethbridge, Alberta
TDI
'04 ALH Golf
The clear line is visible in this picture at the point where it curves around the timing belt cover and goes to the IP.





I see what looks like a lot of damp fuel return lines. If they are leaking fuel out, they will also be leaking air in. This will allow the fuel to drain back to the tank, causing a loss of prime. Since you first had the problem after the car sat overnight, this is the most likely cause.
 

Crusty

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Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Ok,now that I look at the picture, I see it:eek: Most of what y see is actually oil. I changed the oil cooler sandwich o ring, thinking that was the leak, but I now think it is leaking where it mounts to the block.

Would a car that has worked perfectly suddenly go bad over night? To test, I should look at the line while cranking, correct?
 

ToddA1

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Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
I had a starter fail on my the day after i installed it. It jammed up and never retracted. Imagine a starter motor spinning at 4,000 RPM (or whatever that gear reduction is from the flywheel. Well, it literally welded the shaft of the starter in place and left my work van stranded. BRAND NEW remanPOS part. oem baby, you gata go oem on the parts that count!
 

Crusty

Active member
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Feb 3, 2018
Location
Idaho
TDI
98 Jetta
Todd, your link has the same symptoms as what I am experiencing. I just ohm’d the Crank sensor and got 833 between whit and yellow and infinity for any other combination. What should the ohms be? I think this could be my problem

Edit: I just reread the ohms with it set to 20k instead of sound, and it read 1.109

Also, between black and white on the harness end, I get 0.10v with the key in the run position
 
Last edited:

ToddA1

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Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
ToddA1 said:
Pulled the speed sensor and it looked fine, other than a small crack in the insulation. Bentley states it should read between 1.0-1.5K ohms, between pins 1 and 2. Mine tested 100% open.

-Todd
 

Crusty

Active member
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Feb 3, 2018
Location
Idaho
TDI
98 Jetta
I also tested for keyed voltage to the IP harness. It and the injector #3 both were 10.__ volts, so I think we are good for electrical. I just swapped fuel hoses, and am going to get a filter and bleed it all. All the lines are bone dry, and were when I pulled the hoses. It appears to have totally lost prime.
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
I just got back to working on it today. I replaced the fuel lines and the filter, bled it and it fired up. I am not 100% sure what was wrong, but new fuel supply components seems to have fixed it. Thanks to everybody for helping me out. I appreciate it.
 

ToddA1

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Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Was the filter empty? Glad you’re up and running.

-Todd
 

iluvmydiesels

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Joined
Nov 21, 2015
Location
phila area
TDI
AHU
you have to remember to change your filters. fuel filter if i remember is 20k(??)miles, or about 2 years. like it sounds like you did, you prime filter, its also good to prime,add fuel or additive to inlet line. it fills quick, so dont spill. doesnt have to be 'topped off'.
could have been an old filter you didnt change and clogged.(?).
or as todd mentions above it could have been empty.
while your at it get a new air filter and put it in. im not sure how long these std air filters are good for. (20k -??-, also?). air filters are very important to a diesel. fuel filters are similar.
 

Crusty

Active member
Joined
Feb 3, 2018
Location
Idaho
TDI
98 Jetta
I started by checking voltage at all the connections, and filling them with dielectric grease. Then I put in new hoses and fuel filter. I primed everything by slowly pouring fuel in until it wouldn’t take anymore, and then cranked it. The car fired right up,so I watched it for about 10 minutes. I still had some air in the lines, and even though it was running, I stopped and reprimed. This morning, there was still no air, and it fired right up. I have been driving it today. I do get some seeping from the electrical plug on the side of the pump,so I will need to replace it at some point, but for now, I am glad to have it running again!
 

iluvmydiesels

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Nov 21, 2015
Location
phila area
TDI
AHU
it takes at least a few minutes for all air to purge out of system. sitting there idling it may not purge. if its running ok, take out for a spin and see how it goes, and if lines purge.

its also good to prime,add fuel or additive to inlet line. it fills quick, so dont spill
i was going to point out. if you put fuel in the inlet line to prime, Make Sure you filter this fuel first!! i take a bottle of additive and fill up a good ways, and connect.
 
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