Sharing my fix for my recent 90 tsi crank no start no spark

[awdboostin]

Before reading any further this is for 90 cars only as later year models do not utilize the part that was causing my no spark issue.I recently had my 1990 Talon Tsi apart for some maintenance and upgrades and went to start the car for the first time and the car would crank but not start.My fuel pump is hardwired to a switch and has a gauge so I knew it was not a fuel pressure issue as I can read the pressure is normal and hear the pump humming away(walboro 255). Easiest test to do first is to check for spark so that is what I did and I had nothing. I checked the fuel injectors with a noid light for signal just to be sure it was solely a spark issue and they were firing properly. I then checked the CAS and that was also working properly. I am not going into detail on specs and how to check these items as there are plenty of threads on all of them. I had power to my coil and my power transistor also which is located directly underneath the coil. After that is where things were starting to get frustrating. I double checked all of my wiring and connectors also and everything was ok. I then began thinking it was a possible ecu issue with all of the posts of bad ecu's and there high failure rate and how old my car is but I was a mechanic for years and hate just throwing parts at cars and believe in proper diagnoses first.

I then noticed that during cranking my tach was not operating whatsoever which it has always worked fine. With some research on a non functioning tach I came across this thread- http://www.dsmtuners.com/threads/90-model-dead-tach.410779/

It turns out that the "noise filter" on my car was obviously old and broke off at some point during the work i was doing and I had not noticed. I took it out wire wheeled the rust off and managed to ground it properly despite the ear for the bolt hole being broken off. Car fired right up after that and had no issues. I am simply posting because there(or atleast I couldn't find)is nothing posted about the noise filter causing a no start no spark issue. It is posted all over causing a tach not working but certainly not a no start no spark. I just wanted to share my diag incase anyone else has this issue in the future as I had a hard time finding any real data on this small item. I think any info 90 specific is bonus for any of us 90 guys out there since our cars are different than all of the rest. Hope it helps and please move the thread if it could be used in a more specific spot,thanks!

 

[1990TSIAWDTALON]

So what do you think made it not start, grounding of the tach filter maybe grounding the ignition or do you have any idea other than when you cleaned it up and remounted it fired right up. My 90 is down but soon to be put back together with plenty of new parts and I won't forget to move my tach filter over to my new intake, but was just curious as to what you thought.

 

[awdboostin]

It was 100% percent proper grounding of the tach filter. It was not grounded properly and full of rust so I cleaned it as stated to expose fresh metal and mounted it properly and the car started with no issues. Make sure the intake manifold is grounded with the oem ground strap also and you should be good to go. I believe the coil is grounded through its bracket which is then attached to the intake manifold.