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Old 01-12-2001, 09:42 AM
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Join Date: Nov 2000
Location: Jacksonville, FL USA
Posts: 113
Well I decided to work on my no start situation to save myself some money and here is what I found. I pulled each and every spark plug and had friend try to start the car, no spark on every single plug, pulled off distributor cap which looked as good as new, replaced rotor and still no spark. Now here is my real question, can ign. coils go bad to the point where they dont work at all? All of my previous problems seem to add up to an ignition coil problem; hard starts, very poor driveability until warmed up, engine would nearly flood on starts after new OVP was installed, when OVP was installed with engine on car hesitates and almost stalls then goes into FOM. Does this sound like a coil problem? It is a bosch coil, and I took it to an "Authorized Bosch service center" who said they couldnt test it or even find out if it was operating correctly. Anyhow, I tried the MB dealer to find out the price of a new coil and was quoted $156, I also went to the local autoparts store who quoted me $115 for a BeckArnley coil. I searched in partsshop for the part # 000 528 50 03 that was on the coil mounting bracket but it didnt show anything, and the only thing close to what I was looking for in partsshop was for 1987 and beyond 300E's. Please help. Im sorry for such a long and ranting post but I am really frustrated right now. Thank you sooooo much in advance for your help.
2003 Volkswagen Golf GL 24,000 miles. 1.9L I-4 TDI 5spd.

1986 300E. 115,000+ miles. 3.0L I-6 1st daily ride, around town only. (Gone)
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Old 01-12-2001, 09:49 AM
Q Q is offline
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Join Date: Aug 2000
Posts: 839
Yes, they can go bad, and a coil can be tested. I am sure someone here knows what to look for. You will need a multimeter to do it though.
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Old 01-12-2001, 10:28 AM
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Join Date: Dec 2000
Posts: 368
Testing coil

Can't belive they told you that there is no way of testing it.

You need to measure the resistance between the coil terminals.

One terminal is 8mm and the other 10mm.

First measure the resistance between the two. It should be between 0.3-0.6 ohms

Then measure resistance between the 8mm and the center tower where the distributor wire plugs in. The resistance should be 8-13 kohms or 8000-13000ohms

If any of these values are different you'll need to get a new coil.

If the coil is good check your crank position pickup.

It connects to your EZL. EZL is mounted right next to the ABS pump on the fender. It has three plugs, the smallest one is the crank position pickup (one pole). First check if it is loose. Clean and bend the female part of the plug so it p lugs in properly. You can also check the resistance on it.
Take the female part (the wire) and test the resistance between the middle and the outside part. It should be 680-1200 ohms. If not replace.

There is a few more things you can check but check those first.

Good luck,

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Old 01-12-2001, 11:46 AM
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Join Date: Nov 2000
Location: Jacksonville, FL USA
Posts: 113
What else can cause a no spark situation? The Crankshaft position pickup tested out ok, the ign. coil 8mm terminal to the tower was about 7000ohms and the 8mm-10mm terminal ohms was about .35ohms. I ordered a new coil from the dealer (uggghhh) and wont get it until tuesday. I guess if a new coil doesnt fix my problem then I could return it.
2003 Volkswagen Golf GL 24,000 miles. 1.9L I-4 TDI 5spd.

1986 300E. 115,000+ miles. 3.0L I-6 1st daily ride, around town only. (Gone)
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Old 01-12-2001, 04:22 PM
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Join Date: Nov 2000
Posts: 107
Before you pay for it, make sure they will let you return it. In my experience, dealers are often times very reluctant to accept returns on parts, especially something that looks like a special order item. Good luck.
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Old 01-12-2001, 05:42 PM
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
Before you you buy it be sure you need it as this ain't like trying on shoes. You install it, you bought it.

Testing coils for resistance is a fair way to test, but the best way is dynamically with an engine secondary ignition oscilliscope. By openning the circuit total available voltage can be read.

We see many more of the new short coils going bad than the old tall round coils.
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician
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Old 01-12-2001, 06:19 PM
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Join Date: Dec 2000
Location: Battle Ground, WA
Posts: 576
Coil problem?

Hi there,
Thought I'd throw my 2 cents worth in... Stevebfl makes a good point about dynamically testing. Some coils will measure correctly with an ohmmeter, but will exhibit secondary breakdown - the coils will spark over inside due to a carbon trace or other path, and those failures can only be seen with an oscilloscope or by actual operating test. If it were myself doing the diagnosis, I'd swap out the coil before getting too deep in debt for a new one! Any old coil will do for a swap, and you should be able to determine if the coil is at fault or if it is the electronics that is causing the problem. Diagnosis by substitution is probably the best way to go in this case. You might find that you don't have a coil problem at all!

Richard Wooldridge
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