What could cause a no start.....

[turbodsm18]

Ok....First I will start by saying I have researched this quite a bit. Im working on a 95 GSX with minimal mods.

The problem : The car will crank but It will not start. It turned over once for just a second then just dies. The car has slowly been showing signs of weakness upon first startup.

What has been checked : The car has fuel, the timing is perfect, the motor has compression, the ECU is perfect, the Starter is brand new, the Coolant Temp Sensor is brand new, Plugs are brand new, and the plug wires are newer.

Problems Diagnosed so far : There is no spark getting to two cylinders. I have replaced the coil pack for those two cylinders and still nothing. So, if the coil pack is not the problem, What else could cause only two cylinders to lose spark?

My next thought would be the transistor but I dont want to throw anymore money at this car without knowing 100%. What are some ways to check the transistor unit to see if it is getting power?

Any help or advice is greatly appreciated...

Thanks

-Kevin-

 

[Afroclipse]

I'm from 314 babe, I see you reppin that M state.
"+title+"

 

[96gst_4life]

The CAS sensor mabe your problem. if its behind your intake cam gear... i had this same problem wouldent fire on two cylinders. its eather that or your crank angle sensor.. get back to me and let me know where your CAS is..

 

[turbodsm18]

The CAS sensor mabe your problem. if its behind your intake cam gear... i had this same problem wouldent fire on two cylinders. its eather that or your crank angle sensor.. get back to me and let me know where your CAS is..

Its a 95 so the cam angle sensor is behind the cam gear. Tonight, Im gonna swap out the power transistors and see if that fixes anything. If it doesnt then Im gonna test the cam angle and crank postion sensors.

Any other ideas or thoughts, please let me know.

Thanks

-Kevin-

 

[turboglenn]

switch the wires from the igniter/power transistor to the coils, if the other coil then sparks, we know that it's good. If that works use an analog volt/ohm-meter to test the pin from the transistor that's not sparking the coils. hold one lead to the pin on the transistor and the other one can go to ground (set tester to the "Ohm" position and you should see the needle jump if the transistor pulls to ground like it should. You could also put the positive lead of the volt meter on the + battery terminal and then the negative to the igniter and watch for a completed circuit when it should fire the coil. Have a friend crank the motor while you look at the meter. The reason i suggest an analog one is that the signal or pull to ground is going to happen too fast for a digital meter to read out good, so on an analog,just watch for the needle to jump. Test the one you know is good first to see what it's going to do when testing the "non firing" side

If you aren't getting anything this way, try the same test on the wires to the transistor from the ECU. They pull to ground in the same way, they just can't handle the amperage load that the coil would put on it ( this is why you need the transistor to begin with)

After those tests, if you saw no "pull to ground" from the transistor, but did when you checked the ECU wires, replace the transistor. If there's no signal to the transistor, start tracing wires to the ECU, if the wire is good from connector to ECU , there may be an issue with the ECU.

I'm sure a FSM would tell of an easier way to check the transistor, but this is just how i would do it, My FSM got jacked by a customer a few years ago when i had an open shop ( at least i don't think a friend would have stolen it, I'm a bit too old for those types of friends)

 

[turbodsm18]

switch the wires from the igniter/power transistor to the coils, if the other coil then sparks, we know that it's good. If that works use an analog volt/ohm-meter to test the pin from the transistor that's not sparking the coils. hold one lead to the pin on the transistor and the other one can go to ground (set tester to the "Ohm" position and you should see the needle jump if the transistor pulls to ground like it should. You could also put the positive lead of the volt meter on the + battery terminal and then the negative to the igniter and watch for a completed circuit when it should fire the coil. Have a friend crank the motor while you look at the meter. The reason i suggest an analog one is that the signal or pull to ground is going to happen too fast for a digital meter to read out good, so on an analog,just watch for the needle to jump. Test the one you know is good first to see what it's going to do when testing the "non firing" side

If you aren't getting anything this way, try the same test on the wires to the transistor from the ECU. They pull to ground in the same way, they just can't handle the amperage load that the coil would put on it ( this is why you need the transistor to begin with)

After those tests, if you saw no "pull to ground" from the transistor, but did when you checked the ECU wires, replace the transistor. If there's no signal to the transistor, start tracing wires to the ECU, if the wire is good from connector to ECU , there may be an issue with the ECU.

I'm sure a FSM would tell of an easier way to check the transistor, but this is just how i would do it, My FSM got jacked by a customer a few years ago when i had an open shop ( at least i don't think a friend would have stolen it, I'm a bit too old for those types of friends)

Awesome man.....I will test it tonight when I get off work and see what I can come up with.

 

[turbodsm18]

Well, an Update....Swapped out the power transistors and now all cylinders are getting spark but the car will not fire still. I have not checked the cas or crank sensor.

Those I guess are last things left really. Any other ?

Could there be a possibility that the gas in the car is bad. There is less than a quarter tank and the car has been sitting for a couple months.

-Kevin-

 

[96gst_4life]

to me its got to be a sensor and i think its the CAS. and its a pain in the butt to replace be carefull with the cam gear itself dont bend the blades that was the start to my starting problems...

 

[xtreme-elements]

check your cas, crank sensor for 2g's, power transistor, and coils, if those are good and you have spark, make sure your getting fuel..

 

[turbobird14]

if the cas is bad, normally it will fire the car in a random order. when a crank sensor is bad, it just will not start period, if you have spark its probably NOT the crank sensor, i would check the cas for sure and just for the heck of it (and to eliminate another theory) dump some fresh gas into it...especially if when you parked it to now there has been a pretty good temperature change

 

[turbodsm18]

We towed the car behind a truck, dumped the clutch, and it started. No idea why. Now the car will only start sometimes after several cranks and runs really rough at first, but smooths out and runs perfectly once it warms up. Any ideas what could be causing this new problem?

Chuck

Chuckg on turbodsm18

 

[xtreme-elements]

did you check the cas

 

[turbodsm18]

No, but it wouldn't start at all if the cas was bad would it?

 

[Alex928]

Ok i have a 98 gsx with a 91 6 bolt i have no spark and no power to the fuel pump. I have replaced the coils the ignitor chip the plugs wires and the cam/crank sensor i dont know what else to do

 

[turbodsm18]

did it happen to be near or below freezing when you tryed to start the car, watered down gas could also cause a hard start issue

It was very cold when I tried to start the car, but when we finally did get it running I filled it up with new gas. I'm going to replace the fuel filter on Monday since it looks like it's 13yrs old and hopefully that will do something. If not, I'm stumped.

Chuck

 

[gsx951]

Check the coolant temp sensor; the big one with the two wire plug. The wires are thin gauge and like to break close to the plug. When they do, your car will be a mofo to start in cold weather but run fine when the motor is warm.

http://www.dsmtuners.com/forums/search.php?searchid=3894121

 

[turbodsm18]

I've already replaced the coolant temp sensor...could the plug be bad?

 

[97 gst turbooo]

I ran into this problem when i chaged my timing belt. the connector on the back of the top timing cover that goes to your crank angle sensor become loose and would randomly fire up and then wouldnt start. after a while of searchin found a lose connection and problem went away. Try changing the fuel filter and running some injector cleaner. You could also do a seafoam run though.