1G no spark, coil, pt, ecu

TurboFoo · Mar 31, 2015

I got this 1990 awd from a friend a few years ago. He said it wasn't running at the time and thought the motor was blown. We took the motor apart to find absolutely nothing wrong with it. Rebuilt it anyway. Put it all back together and the car wont start. Im not getting spark on all 4 cylinders. I am getting fuel, I drained the tank and added fresh fuel and then primed the system until it filled up a empty 16oz water bottle. All 4 spark plugs are soaked in fuel after cranking the engine for a few seconds. New plugs, New wires, Coil pack tests good, PT tests good, ECU has a pulse but no codes. After unplugging the MAF sensor, the ecu spits out codes 13 and 25. All of my electrical connections are plugged in, except for my AC since i removed it. All fuses are good. Not sure about relays, which relays should i check and how? I took the ecu out and it appears to be fine. Looks good, smells good, no blown caps. What are the odds that the ecu is still bad? What else should i check?

bmxfelon420 · Mar 31, 2015

Did you check the cam sensor? The cam sensor controls the injectors and spark on a 1g. The '90 in particular can have the pigtail coming from the CAS go bad.

DSM1G90 · Mar 31, 2015

Bad temp sensor loves to do this if everything else checks out.

Get that MAF hooked back up again, and dry out the plugs with starter fluid.

Do check out the CAS for I had to replace mine.

Easy test with the ECU (if the stock boost gauge still works..), is switch on the key to ON and the boost needle should hit "zero" and stay there until the motor catches.

TurboFoo · Mar 31, 2015

bmxfelon420 said:
Did you check the cam sensor? The cam sensor controls the injectors and spark on a 1g. The '90 in particular can have the pigtail coming from the CAS go bad.

Well I didn't probe it but I did make sure it was properly adjusted with cylinder 1 tdc and the notch lines up with the mark on the cam sensor. I was told that if the cam sensor was bad that I wouldn't get any fuel... Is that true?

TurboFoo · Mar 31, 2015

DSM1G90 said:
Bad temp sensor loves to do this if everything else checks out.

Get that MAF hooked back up again, and dry out the plugs with starter fluid.

Do check out the CAS for I had to replace mine.

Easy test with the ECU (if the stock boost gauge still works..), is switch on the key to ON and the boost needle should hit "zero" and stay there until the motor catches.

I will check the coolant sensor. I know a long time ago the wires were brittle and broke off and I had to splice in a new connector for it. But from what i remember was that with the wires broken and the sensor not working, i was still getting spark, it just want the right fuel mixture for it to start very easily. I'm going to check the boost gauge

DSM1G90 · Apr 1, 2015

I'm not getting spark on all 4 cylinders

Didn't see this one earlier -- and you mention that the PT tested fine.
Thus, wonder how you did the test to show that the PT was fine?
I would call it that the PT has opened up causing the failure in getting spark.
Also, which plugs are firing and which ones aren't?

If you had no spark at all, then I'd point to the CAS, or the ECU.
But, you mention of some spark, so that can possibly rule out CAS and the ECU as being the culprits.
Could be the PT is giving you fits.

Had to replace my PT and coil pak due to one side of the PT went weak causing misfire.

After the replacements, all is good now.

Good luck - DSM

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1G no spark, coil, pt, ecu

TurboFoo

bmxfelon420

DSM1G90

TurboFoo

TurboFoo

DSM1G90

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