1G 1990 talon tsi no spark. I’m lost

Happys_TSI · Jun 18, 2019

So I pull my car out of storage. Drive it a solid 25-30 miles and the car randomly dies at idle when I get home. Try to start and nothing but the smell of fuel. So I check spark, and no spark. My coils, wires and PTU are all brand new, I put them in last summer. I tested my CAS and it works, I swapped in a new one but still no spark. I did notice while pulling it off there was some oil on the spindle of the CAS.

Could the oil getting on the CAS cause no spark?

After checking that and still no luck I sent my ECU to ECMTuning. They found some issues, here and there, that they fixed but my no spark problem is still there. I checked timing too and it’s all where it needs to be.

So at this point idk, any input would help.

motomattx · Jun 18, 2019

Start at the basics, check for power and ground at the cas, then check for signal output when spinning it by hand, then check for power and ground at the coils, power and ground at the ignition transistor, and output from the power transistor when the cas is spun by hand.

mitsubishikid · Jun 18, 2019

Pull the top timing belt cover off check for slack, Then Get the motor to TDC compression stroke on the #1 cylinder using a large 1/2 breaker bar on the crank bolt, do it by hand, and check to make sure your timing belt did not skip any teeth, if all timing marks line up you should be good on that front, I'd start there before you try cranking it over, just to stay on the safe side, maybe use a compression tester on all the cylinders while your at it just to make sure that all cylinders are good.

motomattx · Jun 18, 2019

mitsubishikid said:
Pull the top timing belt cover off check for slack, Then Get the motor to TDC compression stroke on the #1 cylinder using a large 1/2 breaker bar on the crank bolt, do it by hand, and check to make sure your timing belt did not skip any teeth, if all timing marks line up you should be good on that front, I'd start there before you try cranking it over, just to stay on the safe side, maybe use a compression tester on all the cylinders while your at it just to make sure that all cylinders are good.

This is true, the timing belt may have broken, I guess I'm assuming that he would have known or checked for that.

sacrileger · Jun 18, 2019

Happys_TSI said:
.... Try to start and nothing but the smell of fuel. So I check spark, and No spark.....

check if your CEL stays ON for about 4s when you put the key in the ignition. If not, check this:
1G basic ECU MPI circuit function
No power to ECU

Happys_TSI · Jun 24, 2019

I’ve checked all that stuff several times to see if I missed anything. So after checking every possible thing, I got pissed and started looking for issues w the PTU wiring.

Connector looks good and everything, so I decided to checking for continuity. I start on pin 54, the spark output on the ECU, cuz I’m missing spark on 1 and 4. The multimeter gives no response when testing wire 54. So I test 55 cuz I have spark on 2&3, and it has continuity.

So I swapped out a new wire for 54 and she fired right up.

curt-s · Jun 25, 2019

Nice work tracking it down!

Vincent Pandolph · Mar 19, 2022

Similar problem, no spark/ weak spark in#2 #3. You checked pins 54 and 55 at ECU, where did you check at other end of tester?

steve · Mar 19, 2022

Happy hasn't been around for almost a year so I try and answer for them.

When testing for continuity of a wire you measure resistance from one end to the other. In this case from the end of the yellow wire inside the car at the ECU pin 54 and the other end in the engine bay at PTU pin 7. Same for the yellow wire with red stripe ECU Pin 55 to PTU pin 2.
Because of the distance between the two points you will have to extend the probe so you can reach with another wire that you would check the continuity of first.

This is the 91+ Ignition diagram from the FSM. (the 90 is different due to the tach signal coming from the coils Connector and not the PTU) From it you can see how things are hooked up.

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1G 1990 talon tsi no spark. I’m lost

Happys_TSI

motomattx

mitsubishikid

motomattx

sacrileger

Happys_TSI

curt-s

Vincent Pandolph

steve

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