S300 Running rich after driving for a while

[shane J]

I have had this problem since October last year.

d16-Y8 Custom air to water intercooled JRSC standerd boltons. running stock map sensor, nothing fancy very simple but very powerfull and works very well.
I will be driving my car somtimes for an hour somtimes 25 minutes. Out of nowhere the Wide band will read rich 10.99. When rolling down to a stop the car will struggle to idle and most of the times just stall. When hitting 50% to full throttle the car runs fine. just low rpm below 5000 RPM it runs pig rich.

I have datalogs of this problem that I will post up tonite. If I leave the car and start it the next morning it will be fine. Car will run for a few days just fine and then the problem will happen again.

The AIT's can be pretty low when cruising around 105 to 120F, ECT temps are around 185F. All other parameters look fine. Thinking maybe the sensors were bad but the read fine. Battery voltage is stable and does not jump around

I changed the two items above plus a new o2 sesnsor, and changed the main relay. And the ignitor in the dizzy also cause the car has starting issues when this happens ( I have to pedal the throttle to get it to start).

Weird thing is last night it happened again I drove around and datolged the problem. Turned the car off re burned the map I am running, then started the car and it ran fine. Drove home about 15 minutes and had no problem at all.??

I will post up more info about the set up when I get home and post my datalogs if I can figure out how to do it.

Also a serial number of my S300. I know its about 5 years old.

Thanks Shane

[shane J]

Log has been uploaded

Serial number on ecu is S300- 4074

[shane J]

Forgot to mention problem starts around Just after 14 minutes, you can se the AFR drop to 10.99 and jsut stay there.

[Spunkster]

http://www.hondata.com/forum/viewtopic.php?f=19&t=3772

[shane J]

Car is 1994 honda civic.

D16y8,

Air to water intercooled JRSC Nothing stock is left on the jrsc other than Manifold runners and m45 blower.Blower has two laminova cores running threw it to cool intake charge.

Crower stage two cam and valvetrain. Mild Head porting

T1r D-series header 2.25 exhaust.

ITR Throttle body, stock Map sensor.

Honda obd1 ECU S300- 4074.

Mishimoto Full size integra Rad.

[shane J]

[quote="shane J"]Car is 1994 honda civic.

D16y8,

Air to water intercooled JRSC Nothing stock is left on the jrsc other than Manifold runners and m45 blower.Blower has two laminova cores running threw it to cool intake charge.
Modified S-tube enlarged two 2.5 inchs and more direct path to blower
Crower stage two cam and valvetrain. Mild Head porting

T1r D-series header 2.25 exhaust.

ITR Throttle body, stock Map sensor.

Honda obd1 ECU S300- 4074.

an Fuel lines with Earls inline filter, Fuel pressur regulater set at 55 PSI, 255 Fuel Pump
Mishimoto Full size integra Rad. Not in picture
Thats it. Problem seems to happen on cooler days but can start in 15 minutes to a hour into driving. Most of the time after a couple hard pulls. Problem will only clear up when car is started next morning. Or as a said above turned car off, re burned tune, started car and it was fine.

[Spunkster]

What sensor are you running closed loop off of?

[shane J]

What sensor are you running closed loop off of?

Stock brand new Bosch sensor.

One thing I will not also is when the car is not running good the RPM guage is real wonky and will not respond. Its out a couple thousand RPM, I just assumed that it was just the motor in the cluster. Now it has seemed to fix it self. The car has been driving fine for the last couple days with no problems.

Drove it for a couple hours and no issues.

[Spunkster]

IT sounds like you have some bad connections in your harness. Go through and check all the connectors for corrosion.

[shane J]

Any place you would recomend starting. In the harness? Why would a re burn of the Program im running solve the issue once. Whould that not be something with the ECU..

Thanks

Shane

[chrissmilesback]

i noticed the gear selectors go haywire, 4th and 5th. if that helps :|

[crucian]

If all else fails, do not run in closed loop. Leave it in open loop, give it a real good tune, and everything will be fine; just the way you want it. I'm guessing your supercharger has you idling at 15in/hg. NA and turbo cars may idle between 21-19 in/hg.

[shane J]

If all else fails, do not run in closed loop. Leave it in open loop, give it a real good tune, and everything will be fine; just the way you want it. I'm guessing your supercharger has you idling at 15in/hg. NA and turbo cars may idle between 21-19 in/hg.

It will idle around 20in/hg when running with out the problem. So if I run open loop what is there going to be anyside affects to performance? I just got the car on the road after a month. down with tranny issues.
It was really nice to get out and drive the car but now the problem is still there and have relized this is still a on going issue. I have found a bone stock harrnes to put in but I really dont feel this is the issue. Tonite I tried to re burn the map and this is not working like it did when I first posted the problem.

I did have a good tune 3 hours on the dyno last year.

[Spunkster]

Try the ECU in a known good car and see if the same problem persists. You can also try someone elses ECU in your car and if the problem persists you know it is something specific to your vehicle.

[shane J]

I have a friend coming into town Friday that is leanding me his ECU with is a newer s300. So I will see if the problem is still there. I was hard to find a nother ecu in my town... not many peeps running s300.