I've been using this site and others to try and find out what's wrong with this car. When it first starts, it runs great. Then, a few minutes after driving, it starts stumbling around 3000RPM. After a bit more, it stumbles when you give it any gas. I have so far replaced the spark plugs (gapped to 1MM) and wires, distributor cap, ignition coil, fuel filter ( last owner did this as troubleshooting, they put it in backwards) o2 sensor, and flux capacitor. It was showing a code 43, but it isn't anymore after clearing the codes earlier after doing the o2 sensor. I have disconnected the EGR valve and it makes no difference, and disconnecting the MAP sensor really pisses it off, so that must be working. I tightened the white ring in the fast idle valve and tightened the spade connectors going to the igniter.

I'm really hoping someone here can help me. I dont know anything about these cars, and if you feel like it might be something I've done and screwed up one, let me know. I'm thinking about changing the fuel filter again, just to be safe.

 

This may sound wierd, but how is the condition of your fuel pump? Are you getting good pressure at the rail after the car is warm?

 

Basic test, fuel pressure and as mentioned, what is fuel pressure when engine is not running properly?

Immediately after engine has been running poorly, remove a spark plug(s) and see if engine is running rich, if so, check the ECT sensor, if it's good...

I guess it's possibly an ECU/ECM problem, not adjusting fuel for warm engine, [running temp.]. 94

 

I don't know much about Honda ECUs but it sounds like it having a problem going to closed loop to open loop. Like fcm said, have you tried swapping another ECU in? Are you sure you put the correct O2 sensor in?

 

on a 1990, the o2 will just be a single signal wire. it'll be universal.
what i would do here is install a fuel gauge and watch what happens. if the needle drops before it dies, your problem is fuel related. if it dies, then the pressure drops off, your problem will be ignition. you can then further troubleshoot the problem from there

 

Did you ever figure out what was wrong with your Integra? I have a 1990 with the same problem and I've already lost too much hair to keep pulling it out over this car.
I too thought it might be the flux capacitor but it tested out just fine. As for the other things, I tested them all as best I could, spark plugs, wires, distributor, you name it, everything seems fine except that it runs like crap.
But not when I start it in the morning. It will run great for about five minutes. Soon as it starts to warm up a little, sputter, sputter, lurch, drag, sputter. I can feather the gas a little bit and occasionally get a good running area I can ride through a shift or two but as soon as I significantly slow down or speed up it starts to sputter again.

 

I'm pretty sure after 9 years he gave up or figured it out..

So your Integra can travel back into the Future!!!!!! I wish my Integra could hit 88 mph and go into the future or past LMAO!!






And I'm pretty sure you need to replace your ECT sensor

 

lol. 6eah, normally 88 is as easy as putting a pair of underwear on my head and making a 6" tall goddess appear out of a little dry ice and my sister's Barbi doll. But not with the car running the way it has been lately. (Weird Science)
I kinda figured as much finally on the current problem at hand when I tried the old ball peen method of auto repair by hitting (tapping) the ECT sensor with a wrench and it started running correctly again. I still plan on getting a new one tomorrow though as I've found that the ball peen method rarely works longer than new OEM parts.
But I thank you very much for the help. (I didn't even notice how old the thread was) lol
Have a great evening and stay healthy!

 

haha no worries ! glad I pin pointed the problem for you! the ECT is weird sensor when it starts to go bad the ECU doesn't throw a cell until its either completely not working which I have never seen or a short is present on the plug or harness. But it plays a huge role on how the engine performs when it reaches operating temperatures, And it can cause a huge headache trying to figure out.