1996 Honda Accord 4 cyl Front Wheel Drive Manual 112k miles

I had a bad cylinder in my old engine and it was obviously running extremely rough so i purchased a used engine with 112k miles on it from a certified wrecker. Had a local shop install the engine, swapping all components except for coil and injectors.

After R&R new engine starts and idles rough but has even less power than my previous engine did on 3 cylinders. All cylinders in new engine have over 160 lbs and has spark and fuel. Timing is checked. Computer says the O2 sensors are out on both manifold and catalytic conv. and that it is running too lean.

When driving it feels like the engine is fighting itself for power... revs, but has no increase in torque or acceleration..
Had catalytic converter checked and even went as far as to drop the entire exhaust to see if that was restricting it but no change in power.

Could this be a fuel pump issue? Throttle positioning sensor?
Where should we start? I'm at a loss...

 

Vacuum leaks? Recheck the vacuum lines and then see what that does. If the fuel is too lean, then try another fuel pump.

 

I'll go back and check for vacuum leaks.. Seems kinda random that the fuel pump would partially work since its an electrical component... also trying to find any other solution since that will cost another few hundred that i don't have after replacing the engine already.. Thats a last ditch option... thanks though.. i'm trying to find a fuel pressure gauge to test it today..
any chance that the 02 sensors would somehow both be bad suddently?

 

What codes did you get specifically? You can reset the ECU by pulling the 7.5 amp radio/backup fuse in the engine bay fuse box for a minute.

I would check that the connectors for each O2 sensor are clean and plugged in properly. There are some electrical tests that you can try on the O2 sensor. You can download a shop manual for a 94 accord that will be almost identical to your 96 in the online manuals thread in the DIY section.

 

I will give a simple troubleshooting technique. You have someone break torque the motor while you remove the spark plugs wires from the cap (with the proper tool which is a type of plastic pliers), removing then replacing them one at a time. The cylinder that has the least change is where to start. To break torque you have someone put the car in gear (reverse is the safest) while holding the break and accelerate to the rpm that the engine runs the worst, but before anything else make sure the spark wires are in the right firing order. If all cylinders are about the same you know it is something global to all.

 

I could use some more information. Does it idle badly all the time or just after it warms up? When idling does the rpm go and up and down? One thing that comes to mind is the temp sensor for the fuel injection, if this is disconnected it will run terrible. I think on your car it is on the head below the distributor. You want to start with the basics. I think it is even possible to have your distributor in 180 degrees off the way the shaft is made but wonder would it run at all. You mentioned fuel. Does the pump make a lot of noise? They many times will sound like a swam of bees when failed but I doubt that your problem is a fuel pump.