so, my car will crank over, but it wont fire.

Ive checked spark at the plugs, and none there.

Pulled the coil wire off and tried grounding it to the frame, no spark.

Now, my questions.

Before i go and buy a $60 MSD coil and have it not fix the problem,

1)will the coil still fire if the opti is bad?

2)I've been told that if the opti is bad, it wont even crank, is that true?

3)Whats the likely hood of the ICM going out?

Also, i must add, the car started for me to back it out of the garage, and then would not start. So, it was not a gradual thing, it was just all at once, bam, it wouldnt start.

 

Shoebox has a trouble shooting guide here: http://shbox.com/1/4th_gen_tech2.html#opti_test

 

1) If the opti is not sending signals to the computer, no.

2) No. The opti has nothing to do with engagement of the starter.

3) Not a real often failure point.

 

i replaced coil, it didnt help any.

Got the car to almost start today, it would sputter and act like it was starting, and then just die.

So, i think at this point, i have an opti failure.

 

Checked the ICM harness, the two middle plugs in the harness were not getting readings at all (okay, like .15)

So, according to the site, that means it should be the fuse, coil, or wires inbetween, correct?

 

here is a link to a lt1 no start diagnostic I found a few months ago. Very good diagnostic and write up, as well as a bit more comprehensive (no offense shoebox, I still love your stuff)

http://www.mainstreamtopics.com/foru...p?showtopic=78

 

well, i know my coil is good, bought a new coil, replaced it. Didnt fix it
I have not had a chance to check the ground at the injectors to see if the opti is sending signal.

Since the coil is brand new, im assuming im getting power at the ICM, and i know the ICM is good since i had it tested.

I guess if the opti checks out, im moving to the fuel system

 

take off the TB and remove the connector going to the opti, the link i posted above has KOEO checks for all four of the pins and will diagnose the opti as bad. You may also want to have your battery checked at autozone because of your cranking and probable recharging. Mine was seeing 11.8 volts and tested out bad, so they gave me a free one (still under the duralast warranty). I also ended up have a bad coil. You may have also flooded the engine a little with the constant cranking and no start, if you were firing the injectors, so maybe block open the TB for a few minutes to get some air in there. All of this info is from previous experiences.

 

the battery is brand new, just bought it saturday night.

Coil is brand new, just bought that yesterday.

I will check the opti today.

If the opti checks good, guess i will be checking fuel system next

 

Fuel Pressure? My guess is fuel pump.

 

Good advice.

 

well, ive been testing it since about 2 oclock, went over EVERYTHIGN on that list.

Fuel pressure is good.
Got to the opti test, and the pink/black wire grounds out, meaning bye-bye opti.

So, upgrading to megasquirt now with an edis-8 setup haha.

 

well guys, tore my opti off today and checked it out.

I think i found my problem




when i took it off, there was coolant EVERYWHERE inside.

The seal around the top connector was completely missing, and there was a lot of rust-particals floating around inside there along with a lot of dirt/grime

 

wtf why does your optical sensor say mitsubishi?

 

Because that is the supplier of the module on all of them. If you have a GM opti, it says the same thing.