No start after sitting for a period of time

[93civichatch]

I have been a mechanic for roughly 12 yrs now and I have never been this stumped. My brother bought a 90 Talon Tsi and it for some reason won't start in the morning unless you keep trying for about 10 minutes. I bought a parts car that runs perfect same yr and model so I have all the parts to try. I have changed the ECM,MAFS,Cam/Crank sensor,and injector resistor box. The car has 40 lbs of fuel preasure when cranking also but for some reason the car has no injector pulse with a noid light for like the first 10 minutes when trying to start. I have also replaced the T belt and ballance shaft belt along with all the others and double checked the cam sensor timing. When the car actually starts it runs very strong besides the clutch starts to slip when it hits about 8 or 9 lbs of boost, it has me stumped, if anybody has any other things to look for besides grounds I ahve checked those also please let me know. Thanx

 

[turboholic]

-You might want to look into the capacitors in both ECUs.

 

[Nautica985]

Its probably the coolant tempature sensor. I had the exact same problem.

 

[93civichatch]

I have also changed the coolant temp sensor, sorry for not adding that

 

[Nautica985]

also make sure you are getting the correct voltage to the sensor. My sensor was actually good but one of the wires going to the sensor was cut almost all the way through and it was not getting enough voltage. and one more thing, just in case you dont know there are 3 coolant sensors. make sure you are checking the one for the ecu, the other 2 are for the gauge and air conditioner.

 

[93civichatch]

yes I know there are 3 they all have there own names, 1-coolant temp sensor, 2- sender/for guage, and 3-fan switch and all 3 function properly I have checked all 3 with a multi meter. I have a friends shop up the street that has all Data and for some reason it has a trouble shooter for almost all makes and models but the Talon/Eclipse/Laser. Figures doesn't it? I am also one of the few people around that has bought the newest scanner/logger for all japanease cars it will diagnose skylines and all others. I have used it on this one car and it comes up with no falt codes and all the data looks within spec according to the shop manuels.

 

[philipkrotch]

i kinda have the same prob..but it happens to me when im driving down the road and it warms up. it only doe sit sometimes tho...sorry to steal your thread, but could the coolant temp sensor be my prob too? i was thinking maybe my CAS