k20z1ej1

First, I hate making "help me" threads, i like to figure things out on my own. However, I am truly at a loss here. Im sorry if this seems to be a repetitive thread as i know alot of people make threads about issues with their car before checking anything. That being said, I have checked everything i know to check and i have a few questions.

Heres whats going on-
When i first finished my b18b swap the engine fired right up. No issues at all. I bled the cooling system, let it warm up, and took it for a 5-10 mile test drive. All was well. Later that day i drove to the car home and half way there the engines behavior changed with no signs of anything going wrong. The idle dropped to 400-500, it would barely stay on. Sometimes when accelerating from a stop, it would hit what felt like a soft, artificial rev limiter in 1st or 2nd gear. At around 2-3k rpm it would just stop making power/accelerating and the RPM stayed the same. No matter how much throttle i gave it, RPM would not climb. A few days later it shut off at a light and wouldnt start. I got it home and discovered the coil was bad. I replaced the coil and it fired right up, but the previous running issues still exist. So, what i did was replace the following:

ICM (oem)... no change
distributor cap (oem)... no change
rotor button (oem).... no change
fuel filter... no change
BRAND NEW complete distributor... no change
main relay (oem).... no change
brand new ngk bkr6... no change
new Xenocron 255 fuel pump.... no change
brand new ngk plug wires.... no change
OEM thermostat......no change
new OEM NGK/NTK oxygen sensor...... no change

So, in a nutshell....The idle/running problem gets worse as it gets warmer. When the car first fires up, it seems like it has a random miss. Not a full blown misfire or dead cylinder, just a light miss here and there. It seems down on power from when i first got the swap done and took it for a drive... maybe 20-30 hp. As it gets warmer the idle gets worse and the car seems to miss throughout the entire rpm range no matter if its cold or hot. Eventually after about 15 minutes of driving the car barely runs, idle drops to 400 ish. The engine does this every damn time i drive the car. Please give me suggestions. I welcome any and all thoughts. Thanks in advance.

EDIT: I checked timing belt tensioner and it was a little tight, but nothing serious so I don't think it's that. A guy I work with suggested checking fuel pressure so I'll do that tomorrow. Could a fuel pump going out cause those symptoms?

EDIT #2: I checked fuel pressure and it was 35 psi at idle, measured at the the filter. Everything i read online said that spec is 31-36psi. I replaced the fuel pump anyway with a Xenocron 255 lph.

EDIT #3: I replaced the O2 sensor with a brand new OEM NTK... same ****.
I replaced the plugs with OEM brand new NGKs... same thing.





I dont want anyone to solve my problems, but at this point ive replaced everything i can think of and i just need suggestions about what i can check next.

k20z1ej1

bump. installed a new fuel pump with no change and im at a complete loss here.

If you suggest something to look at it and it turns out to be the problem, i will paypal you $30!

100% serious.

JRCivic1

When you first turn the key on, does the "Check Engine" light come on for about three seconds and then go off when you hear the main relay click and the fuel pump complete the priming cycle ??? If not, fix that first. If so, do you have a "Check Engine" light ??? If so, what codes do you have ??? If not, I would look at a few additional items. The IACV (Idle Air Control Valve) being damaged or stuck closed will cause the really low idle and it will cause the stuttering and poor engine operation below 3000 RPM. You mentioned that the problem seems to get worse after engine warm up, so unfortunately, the IACV doesn't fit that symptom. ECT and IAT sensors influence fuel and ignition delivery... if either (or both) are sending unusually high values back to the ECU, engine performance will in fact suffer. Lastly, a "Lazy" O2 sensor will report false readings to the ECU, and the Closed-Loop operation will be affected dramatically. Usually this phenomenon will ultimately result in a "Code 43" (Fuel System Failure)... since you did not report any codes, I offer this as a "Maybe".

You didn't mention what year your Civic is... if it is an EK ('96-00), there are a few additional items that I can suggest you check.

NVturbo

Does the CEL flash while you're driving? Do a compression check. If one of them is under 50psi, you have bent valves.

k20z1ej1

Cel illuminates when I first turn key to ign on, goes away as soon as I fire it up. Main relay clicks. Pump primes. Fuel pressure is 35 psi at idle. I tested map voltage and it was 5v. I tested TPS and it's 4.9v. I tested alternator, 14.1v. I have verified the iacv to be good. I compression tested it last night. Cold was 170-175 for all 4. Hot was 175-180 all 4. The car is a 1995 civic and it has no codes. I will replace the O2 sensor and check voltage/signal for ECT and iat.

k20z1ej1

i appreciate y'all

k20z1ej1

bump. updates in original post

k20z1ej1

A pic of the ngk bkr6e's i pulled out when i put new ones in....

http://