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toydub · Aug 19, 2007, 11:08 PM

Hey all,

Having a bit of trouble with my jetta (2.0L gasoline - 5spd). Great car, but yesterday, I was coming home from work and it quit as I pulled off from a signal light. It will crank, but doesn't start. (bad enough I had to push it out of the #1 lane off to the side of the street in DRESSY CLOTHES... not a single guy offered to help push either.. grrrrr). :mad:

Anyway, checked my fuses, changed the distributor cap, and rotor and fuel pump. I'm definitely getting spark to the plugs (checked by AAA) but he said he couldn't hear the "hum" from the old fuel pump. With the new pump, you can definitely hear the "hum", however the car has the same symptom - cranks but does not start.

Changed plugs from the non-OEM (2 electrodes) to the new OEM (single electrodes). Did a test with the new OEM plugs and the old distributor and rotor; started right up. Did a quick test drive, but stalled while putting it into the stall to finish the repairs and wouldn't start anymore. Put the NEW distributor and rotor back in place -- same symptom as before; cranks but won't start.

I've checked the coil for cracks, but couldn't SEE any. Could this still be the coil?

Any immediate advice will be greatly appreciated.

Thanks!

TxGreaseMonkey · Aug 20, 2007, 07:47 AM

Thoughts:

. Test all under-dash and under-hood fuses with a test light or multimeter. Here's how:

https://www.askmehelpdesk.com/cars-t...tml#post252145

. Check for codes.
. Replace fuel filter and check fuel pressure.
. Disconnect tachometer wire, which may be shorting out the ignition, and try starting car.

If the car still doesn't stay running:

. Replace Ignition Control Module:

http://www.partsamerica.com/ProductD...pe=194&PTSet=A

. Replace coil.
. Test ECM or substitute a known-good ECM.

toydub · Aug 20, 2007, 09:08 AM

Thanks! I will double check all the fuses/relays; alerady checked the fuel filter & fuel pressure (a-ok). The ECM (?) and the iginition control module will both be checked. Never thought about the tach wire... wow!

I'm still scratching my head about the coil...

TxGreaseMonkey · Aug 20, 2007, 09:31 AM

ECM is the Engine Control Module (computer). It's a giant "power transistor," whose job is to provide the proper voltage to a host of sensors, under constantly changing conditions. Internal capacitors, resistors, and microprocessors fail, mainly due to heat, moisture, and electron migration. The ECM controls when the Ignition Control Module (ICM) is supposed to open and close the primary circuit in the coil. ICMs are problematic components that frequently fail. Basically, they are "electronic points." Coils fail but are not as problematic as ICMs. If you have 100,000 miles or more on your Jetta, I would replace the ICM and coil.

Try to determine what is the "key sensor" on your car. That is, what sensor, if it's not getting the correct reference voltage, will prevent the car from starting. Then, simply use a multimeter and check for that voltage going to the reference wire of that sensor's connector, when the ignition is turned to ON. This will help you test your ECM.

Be sure to disconnect the negative battery cable, before removing or working on the ECM.

toydub · Aug 20, 2007, 09:48 AM

Ahhh, makes perfect sense -- thanks! I'm definitely going to do some more detailed "snooping" with regards to the coil & ICM. I've heard some stories about problems with the ICM... ALOT of them! :eek:

I'm always asking people about "electronic points" and usually I just get that "blank or confused look". :confused:

My jetta has 74K (but my fox has 115... )

... will keep you posted -- thanks again! :)

TxGreaseMonkey · Aug 20, 2007, 10:05 AM

I like that you went back to the OEM plugs that came in your Jetta. I'm not a fan of cross-reference plugs.

toydub · Aug 21, 2007, 09:49 AM

Hey here's my update!

After testing both new and old parts, one by one of course, this is what appears to have fixed the problem completely:

New OEM spark plugs
New coil

The distributor, rotor, fuel filter and fuel pump worked with the new and old parts, but I put the new ones back in place.

Thanks for all the help and suggestions, TGM!! I really appreciate it. Hopefully, these notes will be able to assist someone else out there having trouble.

Thanks again! :)

... and now on to my fox - it's getting jealous from all the attention its big jetta brother has been getting. :D

TxGreaseMonkey · Aug 21, 2007, 10:15 AM

Good job!

statictable · Aug 23, 2007, 01:06 AM

Fule pump relay. You can "jump" the contacts after relay is removed. This will get you going till you get a new relay. Call a local VW shop and they will give you the wire numbers to jump. I have them written down somewhere and if I find them I'll get back to you. Good luck.