98 Jetta No Start Questions

I am new to these cars. I just picked this one up, and it hasn't had a problem yet, but yesterday I couldn't get it to start. It is a 98 Jetta TDI with a 5 speed, and no alarm or automatic locks. I am fairly mechanically inclined, but don't know much about the jetta. I did some basic troubleshooting, and then cruised the internet, but haven't found my exact symptoms. I don't swap parts "just to see" if it will work. Here's what I have:

Key on- dash lights, glow plug indicator, radio, etc.
Hit start- above stays on, but no noise at all from engine compartment.

I looked, and I initially thought it might be a relay, but none of the info I have found agrees with my situation. I also read maybe the ignition switch, but am confused between the key part, and some switch inside the column (with a small screw)

Another thought is the starter solenoid, but I am not sure. There is no clicking at all during this no start condition.

I am looking to doing the more fun stuff to this car, instead of these types of things

Make sure your engine ground connection is clean and tight.
Find out if power is making it down to the starter solenoid terminal when you hit the key start position using a multi-meter, a 12 volt circuit checker light, etc...if no signs of life show work your way backwards to the next connection.

Eliminate the starter from the equation by again making sure you have a valid engine ground connection then, with the trans in neutral, jumper a wire from the plus battery terminal to the solenoid terminal. If it clicks and engages the starter you know that the problem is ahead of it.

The solenoid harness connections can get tattered with age, at least in a Michigan environment. Insulation deteriorates and the weather can turn that wire into green powder.

Testing for voltage at the solenoid is a start (no pun intended), but isn’t good enough. I had heavy corrosion in the 50 wire and although I was seeing voltage, there wasn’t enough current behind it. Splicing in a clean section, beyond the corrosion, cured my issue.

My methodology would be to verify power at the starter 30, then to jump battery power to the solenoid, to rule out the starter, as previously mentioned.

Work backwards, from there. Other than the alarm box (, that you say is bypassed), the only other thing in the circuit is the ignition switch or actual wiring.

I’d verify that the alarm box starter wires are tied together. In some manner.

-Todd

yea, like stated above; at first 'glance' to your problem, most likely electrical. your battery charge may be ok, but if you have a multi-meter check batt volt 1st. should be over 12.5V+. loose connections @batt, starter, other, bad grounding, or corrosion. <1st to check.

Thanks for the replies. I will test for voltage at the actual solenoid. Can you describe the alarm some more? I don't understand it. There is no door chime or anything like that. Also, it has manual locks.

Unless there is a relay that suddenly went bad, I don't see the connection. The car started and now it doesn't-with no change in the alarm situation.

iluvmydiesels said:

yea, like stated above; at first 'glance' to your problem, most likely electrical. your battery charge may be ok, but if you have a multi-meter check batt volt 1st. should be over 12.5V+. loose connections @batt, starter, other, bad grounding, or corrosion. <1st to check.

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Not that I couldn't have overlooked something, but I have already done this. I even verified using two different batteries. It worked with both, but when I swapped the first back in, then this problem happened. I cleaned and straightened the terminals. I am an old truck guy, and they don't have a lot of solenoids and relays. Usually, corrosion will show voltage, but not carry amperage. This seems like there is no power at all, which is why I suspected something like a relay, solenoid, or maybe just a bad wire/connection itself. I will start with trying to direct jump to the solenoid on the starter.

I forgot to say, if you guys have pictures, that would be appreciated!

Did you look for power at the solenoid signal terminal on the starter when the key switch is in the start position?

Not yet. I am not at the same location as the car right now. I did some small troubleshooting, and then had to leave.

The 98 Jettas had a problem with the ignition switch on the column. In addition to the starting problem it would just randomly die while driving. It was related to having too much weight on the key chain. You may want to look into that.

Thanks. I will start with a test light at the starter, and will consider the lock cylinder as well. Thanks.

Sorry for the slow reply, but I finally got to fixing it. I swapped the ignition switch, and we are back in business I am glad to be driving it. I like these TDIs

Crusty said:

Sorry for the slow reply, but I finally got to fixing it. I swapped the ignition switch, and we are back in business I am glad to be driving it. I like these TDIs

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Always a good idea to keep a spare ignition switch on hand!

Steve

Steve Addy said:

Always a good idea to keep a spare ignition switch on hand!

Steve

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So long as it's OEM, I've had too many aftermarket ones fail early.

If the lock cylinder housing is really worn, they will repeatedly tear up ignition switches, and the cheaper switches will just get tore up faster.

The plastic switch is not designed to tolerate a bunch of slop in the action of the little tab twisting in the cylinder.

Not really sure why these have such a bad issue, because they are not all that changed from the same basic design VAG has used in many models for many years, and those did not seem to have any problems. But they cheapened something somewhere.

Never see these cars in here any more though.

Abacus said:

So long as it's OEM, I've had too many aftermarket ones fail early.

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True, the OEM ones do seem to last longer, but they're so expensive now for what they are. I would prefer to use them but many times have not.

oilhammer said:

If the lock cylinder housing is really worn, they will repeatedly tear up ignition switches, and the cheaper switches will just get tore up faster.

The plastic switch is not designed to tolerate a bunch of slop in the action of the little tab twisting in the cylinder.

Not really sure why these have such a bad issue, because they are not all that changed from the same basic design VAG has used in many models for many years, and those did not seem to have any problems. But they cheapened something somewhere.

Never see these cars in here any more though.

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One reason I only run with two keys on my ring. A lot of the problems that came along with the Mk3 ignition switches was a consequence of people with 5 lbs of keys and other stupid junk hanging out of their steering columns. Fewer keys means less stress and less wear and tear on the column assembly.

Steve

I totally agree. I cringe when I see some of the dumbells people have hanging off their keys when they come in here.

'97 Passat, No Start

Good info here, and I will troubleshoot my Passat accordingly. I wonder how similar the '97 Passat's ignition wiring is to Crusty's '98 Jetta. Same symptoms. I believe the 1Z and AHU are similar enough. Don't mean to hijack, Crusty.

cumminsfromthecold said:

Good info here, and I will troubleshoot my Passat accordingly. I wonder how similar the '97 Passat's ignition wiring is to Crusty's '98 Jetta. Same symptoms. I believe the 1Z and AHU are similar enough. Don't mean to hijack, Crusty.

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The engine isn't the deciding factor, it's the electrical system used in the car, and in this case the electrical system for the Mk3 and the B4 passat is the same. I would go so far as to say that the ignition switch and its wiring harness are most likely identical. There are many shared components between the two models.

Steve

'97 Passat no start - immobilizer?

Thanks Steve Addy. I suspected the electrical systems were the same, but getting confirmation is great.
I tried starting the car with pretty low battery voltage, and I know that could cause a variety of symptoms. I'll add a couple of unique symptoms - the red LED by the driver's door was flashing, and the left turn signal kept coming on as I tried starting the car with jumper cables on a battery that was completely dead. The car is a CoPart purchase I just got. the radio has been pulled. With full voltage, we'll see what happens. I have never experienced a TDI with the immobilizer activated and am hoping that's not what's up.

Careful, low voltage kills clusters.

The alarm box is easy to bypass. Simply unplug it and jump the fat red wires in the 6 pin connector.

-Todd

Yes, follow Todd's advice, you do not want to fry the cluster with sub-12v power.

Bypass alarm box before trying and TBH I would unplug my cluster completely before attempting to start. It will start with it unplugged and you don't want your cluster to fry. If glow plugs are working you will hear the relay if you're quiet.

Steve

'97 Passat TDI Cluster disconnect and relay/fuse list

Ok, will do gentlemen. I've read about the frying clusters and some bad grounds, but I am not seeing anywhere how to simply disconnect the cluster. Any links or tips?

I will bring to the car the relay block with fuses and relays from the Toyota's donor B4, which was in excellent shape. LugNut provided this
http://forums.tdiclub.com/showthread.php?t=125127

Oh, duh, and the A3/B4 sticky: http://forums.tdiclub.com/showthread.php?t=204372

Edit- after thoroughly cleaning (filing) each positive and negative battery cable end, battery posts, ground locations, removing and checking every fuse in the relay block and the separate ~ cell phone sized block that appears to be the turn signal relay, I there removed a (still good) 20A fuse and reinserted it. The car instantly started and runs and drives quite well. The $1100 CoPart sight unseen purchase is a win. Hope this helps someone else.

Just so you know, it was a simple job. Took me about 20 minutes to do. The only trick was getting a puller to remove the collar from the steering shaft.