testing 90 Power Transistor

[Empyrials]

So i'm having a hot start issue atm and have replaced the CAS and was trying to test the Power Transistor. I just really want to make sure that i'm testing it right as well that the transistor is dead. Either way i'm trying to get my hands on another one but still, i can't find one in town from ANY auto parts store

ok so i've tested my Power Transistor with this meathod and the Transistor doesn't light the bulb. even when the Transistor is cold. I'm using a AA as the 1.5v source and the car battery as the 12v. No matter what the light buld doesn't turn on(Buld was tested before and after to make sure it works). But my car starts when cold so does that mean that the way i'm testing it isn't right??

As i see it the pins on the Power Transistor was 1-2-3-X-4-5 (x is the missing pin on this unit) If that's right i've been wiring it up the correct way but i'm still questioning myself because the car starts as well as i've yet to test another one


PS: the forum is F'n slow today

 

[luv2rallye]

Your testing it wrong. The pins are 1-2-3-4-5-6 with pin 4 missing (it still counts as pin 4 though). If it runs cold the PT's are probably ok unless there's a heat issue (heat gun or hairdryer on PT will find it).

It sounds more like a vapor lock problem however: http://www.dsmtuners.com/forums/problem-diagnosis/217349-vapor-lock-hot-start.html. If not that see: Hot Start Problem Fixes

 

[Empyrials]

Your testing it wrong. The pins are 1-2-3-4-5-6 with pin 4 missing (it still counts as pin 4 though). If it runs cold the PT's are probably ok unless there's a heat issue (heat gun or hairdryer on PT will find it).

It sounds more like a vapor lock problem however: http://www.dsmtuners.com/forums/problem-diagnosis/217349-vapor-lock-hot-start.html. If not that see: Hot Start Problem Fixes

bah i labeled my txt image wrong, i had the correct pins though, i did it 3 times now and nothing. besides either way i had it with pins 4-6 the first 3 pins should of lit up for cylinders 1 and 4.

I've used the Host start link and done them all.

however i need to see if it's vapor lock i guess, i didn't see the test for that. Removing the vacume line to my AFPR. IF it is that i've have to find a FPS, didn't come with my car . Thanks for the link i'll try that out today

 

[DSM1G90]

I had hot start issues as well .. turned out my ECU needed to be replaced.

 

[luv2rallye]

bah i labeled my txt image wrong, i had the correct pins though, i did it 3 times now and nothing. besides either way i had it with pins 4-6 the first 3 pins should of lit up for cylinders 1 and 4.

The PT test has to work if the car starts so something is wrong in your proceedure or equipment.
1) Make sure you are connecting the battery's polarity correctly as article states.
2) Try a new 1.5v battery (yours might be weak).
3) When you finally connect the 1.5v positive to make the light go on, you still have the 12v battery connected right?
4) Test to make sure none of the wires are internally broken. Connect the 12v light to the 12v battery with each of them and then wiggle them to check for breaks.
5) You do have stock oem PT and wiring correct? The 90 has a different PT than all other years - a 6 pin connector with 5 wires. All other years have an 8 pin connector with 7 wires.
6) Are you counting from the proper connector end and checking wire colors? Pin 1 has yellow/green (yellow with green stripe). Pins 2-6 are then yellow, black, unused, yellow/red, yellow/black.

 

[DSM1G90]

When I made my little power transistor checker, it's good to also know how to solder so you can solder wires to the 1.5v battery and also solder small alligator clips on the loose end when you attach them to the transistor when you do this test above.

For, with this test above, my PT was giving me the light when it was needed making my PT working okey.

 

[Empyrials]

wait wait wait, by reading the procedure i thought i could unplug the PT and test it by connecting my alligator clips to the pins of the PT. It sounds like from you guys that i should leave it plugged in and test it?

i figured since i was using 12v source and all it didn't need to be plugged in. I've also tried different battery's that are new out of the pack so dunno. i just went to check the wire colors and i've been testing the correct pins.

If that's not it well then i dunno wtf the problem is. However i heard one of the spark plugs firing after i turned the car off today when i was testing if Vapor lock was my problem, and vapor lock doesn't seem to be my current problem. I was able to unplug the CAS and it kept clicking, so i'd have to assume PT, coils or wires crossing. I've looked at the wires and they seem to be fine.

My ECU is fresh back from DSMlink with replaced caps and all so i'm assuming it's good, but i've read a lot of people do have the hot start issue with a bad ecu.

 

[luv2rallye]

wait wait wait, by reading the procedure i thought i could unplug the PT and test it by connecting my alligator clips to the pins of the PT. It sounds like from you guys that i should leave it plugged in and test it?

No the PT MUST BE unplugged to test it.

If you still think you have ignition problems:
1) When engine is warm (or when it typically fails) I suggest running or cranking engine in a dark place and watch spark plug cables and coil for any spark jumping to ground. If so check for missing grounds (eg. coil not bolted securely to head) or replace the item (eg. spark plug wire).

2) Check/replace the filter capacitor (small cylindrical tin can bolted to intake manifold driver's side with 1 wire coming out of it). You can check it by just unplugging it and noticing effect. Perhaps it is shorting with temperature.

3) If that ok, then I suggest removing one spark plug at a time, re-connecting it's spark plug cable and grounding the metal spark plug case (or threads) to the block/head either with a clamp or a wire (like a jumper cable). Then have someone crank the engine and you watch the spark jump the gap to see how strong it is. Then reinstall the plug and continue with the next one. Or if you have enough clamps you could remove all the plugs and do all at once. Or if you have only 2 clamps you could do 1 & 4 together and then 2 & 3 (remember 1& 4 fire together and together complete the high voltage circuit so they both must be connected as do 2 & 3).

 

[DSM1G90]

but i've read a lot of people do have the hot start issue with a bad ecu.

Yep, (and to repeat) and I was one of them...

I thought I was also having vapor lock, fuel pump, regulator issues last summer when it was hot. I even carried a can of starter fluid to fire up the motor to get the fuel line cleared of the vapor. I even wrapped the fuel line to protect it from the heat from the block figuring that this excess heat was giving me the vapor lock. I even disconnected the regulator selenoid so I would have a bit more fuel pressure for the injectors.

None of all of this worked until this spring I suddenly died going into town - dead cold.

No ignition, spark - any sort of response - got plenty of fuel for I could easily smell it starting to flood.

Thus, got on here and did some searches on how to test the ignition circuitry. Did the transistor thing first with my homemade testor. Transistor checked good.

Went to the CAS and it looked pretty knarly with the wires due to the 1Ga's CAS is hard wired and uses no plug. Opened up the inside of the CAS..it was spelling disaster inside. "Okey, need another CAS"

Went to the ECU and it was the original, 20 yr old ECU that came with the vehicle. Cracked it open and it looked real clean, but knowing electronics that even looks can be deceiving for defective parts.

My coil was weak also - one side was horrible in resistance than the other. So, new coil.

Well, not messing around with the ECU, got another one from Motoguys on an exchange.

Guess what: with replaced CAS and coil along with the ECU, thing now runs better than when I first got it last year.

...and no more hard, hot re-starts - thing fires right back up no matter now long and hot I drive.

Just my experiences to share with you ... good luck - DSM