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Volkswagen Jetta, Golf, GTI: 1993-1999, Cabrio 1995-2002 (A3) 1996 Jetta no spark


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Last Post: Dec 31, 2010 10:54 AM Last Post By: 57SKIP
Gunlover

Posts: 23
Registered: 06/04/04
1996 Jetta no spark
Posted: Jun 5, 2004 10:19 AM
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I have recently aquired a 96 Jetta that has no spark. When I first started the car, it ran, but smoked really bad. I removed the intake (which was caked with oil), removed the plugs, and number 3 was pretty much demolished. It was covered with oil, etc... I checked, and found that there was about seven quarts of oil in the car, so I drained it out, and filled it to the proper level. While I had the intake off, I soaked it in brake cleaner and scrubbed it out. I did the same with the top of the valves (which were covered in carbon), being careful not to let any fluid leak into the cylinders. Before I did any of this I did a compression test, and found cylinders 1,2,and 4 to have about 150 psi, but #3 only had about 70. I also did a leak down test, and found that #3 had about 60% leakage on the intake side. After cleaning everything, and retesting the leak down, all cylinders are virtually the same 10-15% leak down, and about 170 psi compression. I replaced the plugs, and put it all back together, but there is no spark. I have power and ground to both my distributor, and my coil, but nothing coming out. The car cranks, but will not start. Is there a check I can do on the coil to see if it is out of resistance specs? The only other thing that I notice is whenever I go to crank the car, the oil light flashes. I know nothing about VW cars, as I am a KIA technician, and asians are different than Germans. Any help would be appreciated.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 5, 2004 3:58 PM   in response to: Gunlover in response to: Gunlover
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To get this engine to spark you basically just need input from the engine speed sensor for crank position and output to the coil. Start by disconnecting the 3-pin connector from the coil's power output stage. Check voltage across the outer 2 terminals with the ignitoin on. It should read approx. battery voltage. If not, there's a wiring problem.

Next, remove fuse 18 and disconnect the harness connectors from injectors 1 and 4 and connect an LED test light across terminals 2 and 3 of the power output stage connector (black/red and black wires). Crank the engine and the light should flash. If it doesn't, the engine speed sensor or the wiring to it should be checked next, along with the wiring from the ECM to the power output stage. A check of the DTCs should register if the engine speed sensor isn't working, and this should have been done already.

If the light flashes pry back the cover from coil terminals and connect a test light across terminals 1 and 15 so that you don't have to hold the light in place. Switch the ignition on and see if the test light illuminates for 1 to 2 seconds, and the crank the engine to see if it flashes. If it doesn't but the previous test passed, the power output stage is faulty. If this all seems ok, check the primary and secondary coil resistance. Primary (terminals 1 and 15) should be 0.5-0.7 ohms and secondary (terminals 4 and 15) should be 3000-4000 ohms.

Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 7, 2004 9:52 AM   in response to: Gunlover in response to: Gunlover
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I must be looking at the wrong part. The coil you speak of has a 15 pin connector? The coil that I am looking at is mounted on the bulkhead close to the master cylinder, and only has a three pin connector going into it, and a wire to the distributor coming off of it. Am I looking at the wrong thing? Is there another coil I am not aware of? And when you say disconnect the injector harness on 1 and 4, then check power stage output, you mean from the coil, right? Also, there is no code for the engine speed sensor.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 7, 2004 11:26 AM   in response to: Gunlover in response to: Gunlover
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Attachment coil.gif (13.4 KB)
No, there's no 15 pin connector. Terminals 1 and 15 are standard numbering of terminals on the coil. See the attached picture. The power stage is at the coil

Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 7, 2004 12:39 PM   in response to: Gunlover in response to: Gunlover
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Thanks, I will check on all the info you have provided, and get back with you on my findings, and where to go from there.
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 9, 2004 6:08 PM   in response to: Gunlover in response to: Gunlover
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I have a few codes in the car, and am wondering if it because most of these things are unplugged whenever I try to start the car. I have P0121, P1237-1240, P1544, P1582. I have the intake off the car as well as the throttle body, etc... On the checks that you instructed me to perform with the coil; is that with everything hooked up like normal with the exception of the coil, or does it matter whether or not the other things are hooked up? As far as the ohms on the coil, I tested around 1.8 ohms on the one coil (pins 1 and 15), and 3000 ohms on the other coil (pins 15 and 4).
I guess let me know what to approach next.
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 14, 2004 1:01 PM   in response to: Gunlover in response to: Gunlover
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Thought I would check back in today, and see if you have any more ideas towards this concern, and if there happens to be a remedy. One other thing...whenever you crank over a jetta, should the oil light be flashing consistently? I noticed this happens whenever I crank it over. Is it possible for the coil to not send a spark if it detects incorrect oil pressure? Thanks.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 15, 2004 7:40 AM   in response to: Gunlover in response to: Gunlover
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The primary resistance at the coil is too high, so that may be indicative of the problem. It should be replaced eventually even if it isn't causing the no-start condition.

To do the test with the LED test lamp you need to remove just what I mentioned - fuse18 and the harness from injectors 1 and 4.

P0121 - Throttle position sensor A circuit range/performance
Probably because of having the throttle body disconnected
P1237 through 1240 - Cyl. 1-4 injectors open circuit
Again, because the injectors are disconnected.
P1544 - Throttle actuation Potentiometer signal too high
Probably because of the throttle body being disconnected.
P1582 - Idle adaptation at limit
Probably because of the problems you're having.

Once you get the coil tested clear the codes. Since you have had the throttle body disconnected you may need to perform a throttle body adaptation afterwards as well. But you can concentrate on the spark problem first.

And no, the oil pressure warning system won't disable the ignition.
Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 15, 2004 4:14 PM   in response to: Gunlover in response to: Gunlover
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I did the check on the coil power stage output, and this is
how I did it. I placed three leads in between the coil and the harness in order to be able to back probe and get my readings. I did this in order to keep the circuit intact. I got no pulse from pin 2. It looks as if the next step is to check the engine speed sensor. Is this the same as a crank angle sensor on other cars? Where might it be located, and what do I need to do in order to check for proper operation. Thanks again for all the help so far.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 15, 2004 4:56 PM   in response to: Gunlover in response to: Gunlover
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Assuming I understand you correctly, which I think I do, you just used the wire leads to extend the contacts of the harness connector right? If so that's perfectly fine. VW actually specifies using a special harness adapter for doing this. I also assume you had the test light between pin 2 and 3 (signal and +V) as stated above, and that you know the test light is working (check between the battery terminals if you're not sure). Realize, too, that many LED test lights only work when hooked up in one direction, so make sure you had it hooked up in a way that should have flashed. Also, make sure you checked for voltage across the outer 2 terminals first before you did this test. Otherwise, the results are meaningless.

Assuming that you had everything hooked up properly and ran the test properly, which I suspect will probably be the case, the engine ground signal from the ECM is missing. Here's what to do:
With the ignition off, disconnect the ECM harness connector. Check resistance between pin 8 of the ECM harness connector and pin 2 of the power output stage connector. You should get 1.5 ohms or less. If you get high resistance or infinite resistance (open circuit) then you have a problem with this wire. You'll have to find the source and repair. Post back if you need help to do so.

If that checks out, the engine speed sensor (crank angle sensor is the same thing). This signals the ECM as to the position of the engine in it's rotation so that it knows when to fire the injectors and activate the ignition. There are 3 wires going to the engine speed sensor, which itself is located behind the oil filter. One is black, which is grounded. Check it for continuity to engine ground, as well as the ECM pin 56. Another is green and goes to the ECM pin 68, and the third is red and goes to the ECM pin 67. Check both these wires for continuity between the engine speed sensor harness connector and the ECM. Then, check the wires for shorting between eachother. If you get a resistance reading below infinite ohms there's a short somewhere.

Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 15, 2004 5:57 PM   in response to: JoeBean in response to: JoeBean
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Yes, that is what I did with the extension of the harness. We have them for the KIA's, so I figured it would work for this as well. As for the ECM, I am not sure where to find it, but I will assume that it is under the dash somewhere. Is there a certain way the pins are directed? As in left to right, or up and down, and are they labeled anywhere on the ECM? Any help with that will get us on with this problem. Thanks so very much.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 16, 2004 6:03 AM   in response to: Gunlover in response to: Gunlover
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Attachment 1.gif (13.6 KB)
Attachment 2.gif (12.0 KB)
The ECM is located in the fresh air intake plenum in the engine bay. See the attached pictures. As for the pin #s, they are in a logical order left-to right, then left to right on the next row, as you would read a page of text. The question will be which one is #1. The connector may be labelled with pin #s or you can just try the 2 possibilities.

Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 18, 2004 5:14 PM   in response to: Gunlover in response to: Gunlover
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Terry,

Hey man. I talked to my service manager who knows a guy that is a VW tech, and has been for years, and he told me that there is a relay under the dash somewhere close to the steering column that could be causing my problem. Said it may be relay 109, or in slot 109. Does this mean anything to you? I guess let me know what you think.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 18, 2004 6:48 PM   in response to: Gunlover in response to: Gunlover
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He's referring to the ECM power supply relay. It could be stamped on the top 30, 109 or 288. That would cause the ECM to effectively not start up. If it's working you should feel it click when you turn the ignition on.

Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 21, 2004 3:14 PM   in response to: JoeBean in response to: JoeBean
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Alright, here's what I did. I removed the main amp relay, and the connector to the ecm. I checked the continuity to the coil, and it checked out .01 ohms. Pretty much perfect. After I ohmed it out, I applied some stabilant 22 to the harness side of each and every pin, and reinstalled it. I then put the relay back into the relay box, and thought, what the ****, I'll try and start it. I cranked it, and saw a spark from the plugs. I hooked up a plug wire to the coil, and got spark coming from it. The only thing that I noticed is that the spark coming from the plugs, from the distributor only sparks on first crank, as does the coil. I am assuming that is normal, but I do not know. I guess, if there is anything else I should try, let me know.
-brent
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 21, 2004 6:13 PM   in response to: Gunlover in response to: Gunlover
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What do you mean exactly by "only sparks on first crank"?
Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 22, 2004 8:18 AM   in response to: JoeBean in response to: JoeBean
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whenever I crank the car it only sparks one time on the intial turn of the key. Either from the coil, or from the distributor.
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 22, 2004 10:26 AM   in response to: Gunlover in response to: Gunlover
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It's likely only sparking once because of no signal from the engine speed sensor (crankshaft position sensor), or because the ECM isn't communicating with the ignition system because of broken wires, a damaged ECM, or power supply failure to the ECM.

Terry
Gunlover

Posts: 23
Registered: 06/04/04
Re: 1996 Jetta no spark
Posted: Jun 22, 2004 12:46 PM   in response to: JoeBean in response to: JoeBean
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So, do you think I should maybe replace the power relay? Also, is there a way to monitor the ESS to see if it is reading rpms correctly? I know on our scan tool we have a current data section that will let us monitor rpm of the engine, but I don't think it will work with the VW. Is there any other way to do it?

Brent
JoeBean

Posts: 4,697
Registered: 02/14/02
Re: 1996 Jetta no spark
Posted: Jun 22, 2004 2:27 PM   in response to: Gunlover in response to: Gunlover
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I'd just jumper between sockets 30 and 87 where the relay plugs in to and see if that solves the problem before replacing the relay itself.

The diagnostic trouble codes should store a code for a faulty engine speed sensor if it's not working. Check the codes with an OBD-II scan tool.

Terry

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