Rep Power: 0

Hi ive got an 1992 honda civic si and it just progressively started having starting issues. Whenever i get into my car and start it up cold it runs and maintains a great idle. I can drive it for hours with no problems (runs cool and clearly has good fuel pressure). The problem is once it warms up i believe. Every time i shut it off then turn it back on it runs and then slowly dies off. Right after it dies it wont start at all, just cranks. i can make it happen almost every time i go for a good drive and it is very annoying because my job entails driving. I had an error code 43 but i popped a new o2 and it went away (clearly not the problem). i know its not the main relay because it suggested to be replaced but nothing ended up changing. If anyone has any suggestions then they would be greatly appreciated.

 
Rep Power: 285

I was going to suggest checking the main relay, because the symptoms you described are exactly what a bad MR normally cause. Did you replace it with a new unit, or a second hand one, do you know how to check the solder joints?

Go back to the basics:
Check fuel pressure, Check for spark, Check the timing, Check compression.

 
Rep Power: 0

I believe the shop just threw a new relay in. I will do as you have suggested. The thing i find most curious is the fact that when i shut it off and then start it up, it actually runs for a second or two but loses rpm fast and then diesels its way out, (while giving it gas sometimes does save it). But every time after that has happened it'll crank for days and there has not once been an exception. *Every time it dies out it wont start back up*. Wait a bit and shes good to go. like wtf