Hey guys I think I have narrowed this no start to the ecu but I want to make sure, because they are pricey areound here.

So issues started with a couple random shutdowns while running, nothing for a while, then trouble starting once and a week later no start at all. I am getting really weak orange spark. There doesnt seem to be battery voltage at the dizzy when I checked, fuses are good, grounds are good. This is an autocraptic 90 dxsedan btw.

Have even tried a known good dizzy.

Thanks for any input, I have to get this thing running asap!

 

Have you checked all grounds and the Main Relay?

 

grounds seem good, is there one right near the ecu? I could check that out. I was under the impression the main relay was for fuel delivery, and that is all good.... I do have a spare though, if you think that may be an issue....

 

Try a new main relay

 

tried 2 new relays, no good. It may be my eyes but it looks like the spark is whiter now? but still seems dull.... im new to this trouble shooting thing though.

Ive got good fuel pressure tested by backing off the bleeder on the filter....

 

so for good measure I just tried spraying brake cleaner in the intake to see if it would react to any spark and no go on that, so pretty sure its spark for sure.

 

Change the ignition coil inside the dizzy

 

already tried a known good dizzy and wires

 

OBD 0? Usually if the computer is bad the LED will just stay lite.

 

No led action here....fak. well... going to check compression tonight just in case shitty thing is this car is going to scrap in two months because I have a cheap new daily all lined up just need it to work that long lol!

 

No one has any more input?

 

Dont have time to check compession but I know it wolt be that.... was running great before. So what can cause a weak spark? I dont get a reading at dizzy of 12v. My tester is poop but I dont get the same reading there as when I go - to + on the battery. Dont get a reading at all at the dizzy.

 

I highly doubt Its the ecu, very unlikely that It would go bad...not saying that they don't...was the car running right before it started acting up ? have you ran it hot/overheated at any points In time ? you confused me when you said you have "no spark" with the title, but as I continued reading your replies you say it has spark but its weak ? If the engine has spark/fuel/compression/correct timing It has no other choice but to run, little things like grounds/relays/fuses/ect...are the only things that can cause a no start issue....go over and double check everything. Last but not least, you can try another good ecu and see If It fixes the issue...I think Its your dizzy or main relay to be honest, but you said you already checked the two...I'm clueless of what It could be..

 

not your ECU since you are getting spark.
Weak spark isn't generated from the ECU.

Take a set of jumper cables and hook one end to the neg cable on the battery and the other end to an ear on the dizzy.

If you have weak spark and you have changed out distributors, plug wires, and plugs (like you said you have done) then it's usually a bad or weak ground.
Jumper cable will ensure a solid ground.

Other than that, it sounds like a bad ignitor or main relay.
... both of which you said you replaced so... dunno =(

 

tried the jumper cables, no go. I am getting gas smell at the intake when I turn it over so that tells me that gas is a-ok....

 

I am assuming the dizzy between 89/91 are interchangeable? the dizzy I have tried is an 89, my car is 91. I am picking up a digital mutimeter tonight, because I dont trust mine....

 

Timing...check the marks and the belt. Also, was it running and then stopped? How was it before and what happened?

 

I concur with the gentleman from georgia, check timing

 

did you change the spark plugs

 

It was running fine, sat for a couple days and didnt fire. But there was the odd weird thing like it took a long time to fire a couple times ranndomly and shut down once, this is all over the course of like 4 months and a few mishaps. havent changed plugs but they all look good and they would not cause this....

 

Ill pull the timing cove this weekend, I dont have the time till then with kids and such.

Thanks much for all the input guys, learning along the way!

 

Just an idea from experience, I had my main relay crap out and went to orielly auto parts to get one and they gave me one put it on and no go tried another and no go. Then I went and borrowed one from a friends car and started right up. Turned out oriellys had given me the wrong relay. just an idea.

 

Pretty sure i know what your problem is but this site is awesome and im sure it will help you for i am terrible at explaining my thought in text form! lol

http://techauto.tripod.com/

 

It seems like coil of flooding, but most likely coil.... maybe the dizzy that I am trying has a coil that went bad? It hadnt been used in 4 months or so.... sucks that they are over 200 to buy here, I may as well drive to the city and buy a new dizzy for 125 lol! so thats 5 hours of driving. ugh.

 

Thats an awesome link btw, wagon talons