1G Cranks doesnt start!!!!

[amtsi]

Im new dsmtuners - glad to be here. Ive owned my 90 tsi awd for a month, basic mods. Last week the car died on me while driving. It cranks healthy but wont start. I did several hours of research on figuring out the problem without wasting anyones time but Im getting desperate now. Ive found mixed answers on the issue.
I checked for 12vdc (red wire) going to the CAS and came up 0. I did a continuity check from the black wire of the CAS to battery ground and checked out good. From what Ive read (mixed answers) the source voltage to the CAS is from the MPI relay. I checked the fuse (good fuse) marked MPI and did get 12vdc. I did remove the #1 spark plug to check for spark and got nothing (yes I did ground the threads). I am getting fuel out of the fuel pump but only checked that. I bought a used transistor power unit in good working condition, swapped it and that didn’t resolve the problem. Removed the Ecu and visually I dont see any problems.
My first question is – if the key is in the “on” position should I read CAS source voltage as 12v and if so does the MPI relay have anything to do with it?
Second question is when I removed the MPI 30amp fuse from its housing I measured 12volts on one side but strangely enough read about 6 volts on the other side. I assumed I should read 12v on one side and 0 on the other side.
Third question is – the MPI relay is located next to the ecu?
Any help would be great. Thank you

 

[luv2rallye]

1) Yes with key on the MPI relay should be activated (by the ECU grounding MPI black-blue wire) which supplies +12V to the CAS red wire.

2) +12V on one side is correct. Anything is possible on the other side since you may get back voltage through other devices.

3) Yes the MPI relay is located next to the ecu.

Here's a 1g ECU power up explaination: http://www.dsmtuners.com/forums/new...ht-need-help-troubleshooting.html#post1521402

 

[Geier]

Coolant temp sensor, ECU, timing belt.

 

[amtsi]

thanks for the reply guys. Im going to replace the mpi relay and see what happens. If that doesnt help than the ecu is next. It only makes sense that the CAS source voltage not being there is causing my problems. Ill keep my results posted for future reference.

Just a quick update: I read on this forum that if the check engine light doesnt come on with the key in the on position its probably the ecu. I just tried that and the engine light didnt come on!

 

[amtsi]

I looked at the ecu one more time. This time i removed the (3) caps from the board and found that they did leak. The leak did cause some damage to the board. I was confident that If i replace the three bad caps and possibly some board traces everything would be fine.....I was wrong. Word of advise, and i should have known this working in an electronics lab 10 years ago. Make sure you have a good quality high watt soldering iron and not some cheap crap 10 or 20 watt iron that i dug up in my garage. Long story short my next step is to find a used ecu that comes with dsmlink. My new 60watt iron is ready!