Dieing CAS?

[92Talon251]

Have a 92 talon Tsi AWD today it has decided not to start after pulling the plugs cleaning them and checking and trying again the car isn't getting any spark.
The ignition coil is only a few years old. But the CAS is as old as the car. The car became harder and harder to start over the past few weeks, it would take multiple attempts to start before it would finally fire. Is this a sign of a dying CAS??

Thanks

 

[steve]

You have a 1G so are you talking about the CAS or something else?

 

[92Talon251]

Yes i mean CAS my mistake

 

[steve]

The electronic part of the CAS is pretty robust. It's LEDs and phototransistors in the green top CAS and Hall Effect sensors on the black top CAS. What goes bad is the wires and seals. There is a oil seal to keep from flooding the inside of the CAS and a cover seal to keep water out. Both can dry out and harden allowing oil or water to reach the inside and ruin the sensor.

Over all the 1G CAS is pretty reliable and when they do fail it's usually pretty black and white, rather than intermittent. There are lots of less reliable parts that could cause the car not to start and the first place to look is at the ECU.

Does the CEL turn on for 5 seconds and then turn off when you first turn on the ignition?
Does the boost gauge move to 0 and sit there until you engage the starter?
Does your fuel pump turn on when you engage the starter?
If you remove the CAS from the head (put the engine to TDC first and mark the CAS body position) do the injector click and the fuel pump turn on when you rotate the CAS?
What is your compression?

There is a whole no start article in the site Technical Articles. http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html

Since it was working before you did whatever you did to the spark plugs it's likely that the soultion will be simple but you still need a plan to diagnose it.

 

[92Talon251]

The electronic part of the CAS is pretty robust. It's LEDs and phototransistors in the green top CAS and Hall Effect sensors on the black top CAS. What goes bad is the wires and seals. There is a oil seal to keep from flooding the inside of the CAS and a cover seal to keep water out. Both can dry out and harden allowing oil or water to reach the inside and ruin the sensor.

Over all the 1G CAS is pretty reliable and when they do fail it's usually pretty black and white, rather than intermittent. There are lots of less reliable parts that could cause the car not to start and the first place to look is at the ECU.

Does the CEL turn on for 5 seconds and then turn off when you first turn on the ignition?
Does the boost gauge move to 0 and sit there until you engage the starter?
Does your fuel pump turn on when you engage the starter?
If you remove the CAS from the head (put the engine to TDC first and mark the CAS body position) do the injector click and the fuel pump turn on when you rotate the CAS?
What is your compression?

There is a whole no start article in the site Technical Articles. http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html

Since it was working before you did whatever you did to the spark plugs it's likely that the soultion will be simple but you still need a plan to diagnose it.

Thank you for this steve! I will get back once I have read the link and done all of the following

 

[92Talon251]

OK, after pulling the out the ECU I'm looking at this mess! Can the ecu be cleaned and reused? Excuse the crappy camera phone pics, The red drawings are where the problems are. There is black buildup on the connections under the little riser piece. Where I have the little red circles there are small amounts of rust on the connections.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[steve]

That part is IC110 and it will have to be replaced. You can see how the electrolyte has wicked up the back side and damaged the film resistors there. I can't tell if the ECU is an EPROM version of not from the subset you've shown. If it's not, I'd look for a replacement that is in better shape.

IC110 is also the part of the ECU that activates the MPI relay and turns the power on to the rest of it.

 

[92Talon251]

I'm guessing the ECU isn't a EPROM ECU since the chip is soldered into the board

 

[steve]

I'm guessing the ECU isn't a EPROM ECU since the chip is soldered into the board

If it has the EPROM on the board it's one. They don't come socketed from the factory. Too bad nobody replaced the original caps before they puked their guts out.

 

[92Talon251]

I just looked at a EPROM vs non EPROM ecu I have a Eprom ecu! I'm guessing some body like dsmchips could fix and clean everything up correct?

 

[steve]

. Yes somebody like DSMChips.

 

[92Talon251]

Mark this as resolved I know what I need to do