So I bought my first Honda, a 94 EG hatch with a d15b swap in it. I inspected it, drove it multiple times before buying it. Ran like a champ other than a idle problem witch was fixed by putting the correct ECU in it. With the new ECU it had no CEL on. One day on my way to work one day it started bogging really bad, couldn't maintain a constant speed. When the car is cold, it runs like a bat out of hell. After the first few miles after it has been running it is almost undrivable. When it gets to operating temperature it runs better, and is driveable but is still bogging bad. Things I have replaced being...plugs, wires, distributor cap, rotor, timing belt, throttle positioning sensor, and the idle air control valve. At this point I am lost, any help would be much appreciated. I want to stress the point at how different the vehicle runs at different operating temperatures. Thanks for reading.

 

I forgot to mention that there are no CEL on at this time. If you put the pedal to the floor, it acts like nothing is wrong at all...even when the car is at operating temp.

 

What D15b engine and what ECU?

 

Ronj, it is the d15b JDM motor. I'm not sure if there is anything special about the block, but the head is the p08-3. The ecu I currently have in it is a p08-000 I believe

 

PO8 or P28 ECU?

Does CEL work?

Have you adjusted the ignition timing?

 

RonJ, when I put the timing belt on I made sure everything was lined up on the gears. I did not adjust the timing on the distrubutor, after doing this. I will check it in the morning. The CEL does work. It comes on every now and again but goes away after the car is turned off. The ECU is a p08-000. I'm looking at it now.

 

Read the CEL sticky at the top. It tells you how to recover the CEL code you're missing.

 

It rarely comes on, but next time I catch it on I'll read it.

 

Ok, so it came on again today. But I read the sticky and my jumper plug doesn't match any of those descriptions. I also replaced the fuel filter and coolant temperature sensor to no prevail.

 

There's a 2-wire connector nearby.

 

Ok, So I jumped the correct plug. The check engine light flashes once every 3 seconds. It a very quick flash, and timeD the flashes about 3 seconds apart. I am still trying to figure out the timing. I see the 3 marks on the pulley. But I have no idea what I'm suppose to be lining it up with.

 

If it's only one flash separated by 3 seconds (a pause) then that should be code 1, which is Oxygen Sensor 1 (A). Could be a bad O2 sensor or it could be corroded wiring or bad wiring between the O2 sensor and the ECU.

 

Test whether unplugging the O2 sensor eliminates the problem.

 

Ok, so I adjusted the timing with by moving the distrubutor towards the fire wall. It was retarded a bit a for some reason, but after adjusting it, it definitely pepped the car up. It was still bogging when at running temp but not as bad. Its was still undrivable during the "warm up period". So I unplugged the o2 sensor, boom. Doesn't bog at all, during warm up or running temp. So I ordered a new o2 sensor, with a set of of eBay headers. The 02 sensor currently on the car will not come off. I inspect weld's as a career and will put the eBay headers through a process we use at work to test welds, which will be interesting. If you would like to see the results let me know and I will gladly post them.

 

Please post pics of the results.

 

Ok, sorry for the late delay. First topic. I put the eBay headers on with a brand new 02 sensor. I'm still having the same symptoms when the 02 sensor plugged in. Unplugged the car runs fine other than idling the rpms move up down about 350rpms, moves back and forth. I honestly don't know what to do from here. The ecu is throwing a code now for the 02 sensor when it's plugged in, but rarley. It will run fine if the 02 sensor is plugged in and the cel is on. But if it's plugged in and does not throw a code it runs like ****. I just unplugged it, it's pissing me off. My oil also smells like someone dumped a gallon of gas in it, and it's has less than a 1k miles on the oil change. I'll post a result here in a second of the results of the eBay headers.

 

Here are some pics of the process I use. It's called FPI. (Florescent Penetrate Inspection) What this stuff does is find every little surface indication. Just finds it was down inside the indication.

 

Looking at the weld's before I painted them they actually didn't look to bad visually. Alot of them were filett weld's meaning the weren't full penetration welds. But looking @ them after the paint I found 3 spots with lack of fusion and 2 cracks. Lack of fusion is pretty much what it sounds like, the weld did not fuse to the metal. These would have failed horribly in the Aerospace industry. I also had a problem with the flange not matching up perfectly to the tubes., so I grounded them down and took off the sharp edges. Keep in mind I paid 45$ for these headers, we shall see how they do.

 

The replacement O2 sensor seems to be bad. What brand? New or used?

 

It was a brand new Denso.

 

The only other thing I can think of is a bad ECU. Have one to swap?

 

Yea, I already swapped the ecus. It did it with the old ecu also. Could the wiring going to and from the 02 sensor be bad maybe? Would that cause these symptoms. Because It was converted to a 3 wire o2 sensor and there are wires running everywhere. Also, how many coolant temp sensors are there? I've replaced one but found another sensor that looks like it reads coolant near the thermostat housing. I say it looks like it read coolant because it screws into where coolant is.

 

I've not heard of a Civic 3-wire O2 sensor, only 1-wire, 4-wire, and 7-wire. More details?

 

I just looked at it, 4 wire my bad. Converted from 1 wire to 4 wire

 

Okay.

What ECU and how was the wiring done?