Thought that started in 93?

 

Why do you have both pins listed for the injector. Why is 34/35 listed.

 

Yes, I have a California car... although I am not too certain if the hood was changed out during its previous lifetime. I know I have only 1 cat and 1 o2 sensor.


I have tested my injector circuits and everything checks out fine. I ground pins 21/22 on the U1 socket and inj1 and inj2 LED turns on. I am so lost...
I referenced this site to help troubleshoot the injector driver circuit:
http://www.diyautotune.com/tech_arti...leshooting.htm

 

That is precisely it. 2 wires coming out of pins 34 and 35 bridged together by solder and connecting to the according injector pin.

 

Why do you have both 34 and 35 connected to the injector wire?

 

Because pins 34/35 drive injectors 2/4 (bank 2, in batch fire mode)

I did the same thing with pins 32/33 for injectors 1/3. (Bank 1, in batch fire mode)

 

makes sense. Different than ms3. But I've never played with ms2.

Did you try swaping the wires around and seeing if the wet cylinders switch?

 

Outcome: I switch bank1/bank2 on my harness and the misfire did not go away. However, there were no wet plugs. Injector 2 and 4 did have more black soot than 1 and 3 but all plugs did remain dry.

The misfire note seems a bit closer and smoother now. The revs are peppier. I wonder if my copper plugs are done from all the fouling and such.

I am now stuck between a rock and a hard place....

 

Did you put new plugs in?

 

I bought a fresh set of BKR7E's and that did not help at all. I confirmed after that 2 of the 4 injectors are not firing.

I'll test for continuity again from the MS harness to the injector harness.

 

Which 2 arent firing. Stop doing random stuff and figure out which ones arent firing and why.

 

The ones that were dry when he checked the plugs, I'm guessing.

 

But he didnt swap the wiring and check again. Because that would narrow down the problem.

 

Right, and he should have.

 

Are you using output test mode to test this?

 

So I switched Inj1 and Inj2 with pins 32/33 and 34/35, basically swapped the banks. As expected, injector 2 & 4 stopped working which initially was 1 & 3.

As of right now, I checked for 12v on each lead on the 4 harness plugs and they checked out fine. I also checked continuity from the injector harness all the way to pins 32/33 and 34/35. Continuity as expected.

This leads me to the board. I have the MS on the bench hooked up to a Jimstim. I also have 2 injectors with the pigtails hooked up. The black wires is hooked up to constant 12v, and the green/white wires hooked up to injector bank 1 and 2 respectively.

Injector bank 2 is non responsive. This is my issue. What is weird tho, I tested the injector circuit by grounding pins 21 and 22 on U1 and the LED's for inj1 and inj2 turn on. Based on the link I provided above, this indicates the injector drivers are operational....

however, I don't think that is the case based on where I am at now.

 

I only read teh first post:

you messed up on your wiring and you probably only have 2 spark plugs or two injectors firing.

 

the LED circuits are for Spark, not injectors.


The injectors are run off the U4 IC. you probably should inspect how you build the board and see if youre not missing something on the injector circuits.

 

Thanks Braineak for your help. I appreciate it.

I am currently focusing on the U4 IC and all other components to ensure continuity and that certain voltage values are present in on/off conditions.

When I was referring to LED, I was referring to the JimStim LED's that are marked Inj1 and Inj2, not the LED on the MS.

For testing, I connected an injector to the JimStim to replicate what is on my car. I hooked up one end of the pigtail to 12v and the other to Inj1 and Inj2 terminal on the jimstim. The injectors pulse on inj1 terminal which is expected. When I connect to inj2 terminal, NOTHING - no response or clicking.

To my luck, I shorted something on the JimStim while connecting the Injector and now my C1 and F2 are shorted (assuming) because they both get hot as hell after a few seconds of the jimstim being on. Then after a few seconds, the jimstim stops powering the MS.

Thanks for the help again. My plan to address the short on my JimStim so I can continue troubleshooting the U4 IC.