I have a 1995 Civic coupe. I had a GSR motor built previously, but after 3300 miles, I found that the builder didn't gap the piston rings. With heat and expansion, the ring ends came together and distorted the rings and one was broken. This caused high oil consumption and high smog emissions.

I just had a new motor built by Laskey Racing in Anaheim, CA. Here's my setup now:

1) B18C1 block
2) 89mm balanced LS crank / Eagle LS rods
3) CP 10.0:1 compression pistons / CP rings 0.017" and 0.019" top and bottom gaps
4) Stock Civic airbox with KN filter and B16A intake tube
5) OEM GSR throttle body taper bored from 67mm to 64 mm with port matched GSR manifold.
6) P72 GSR head with ITR valves, ITR springs, ITR cams, and Crower retainers
7) OEM 270cc injectors with STR fuel rail and AEM FPR
8) STR/BDL adj cam gears
9) Comptech header, Jackson Racing high flow cat, Greddy exhaust
10) Jackson Racing 160 degree thermostat with Mugen low temp fan switch
11) P72 OBD1 ECU with socket and jumper switch (stock versus reprogrammed chip in socket)

I got the new motor running for the first time last week. It has a BRAND NEW fast idle valve on the TB. The O2 sensor was brand new with the previous motor, but I'm worried that excess oil buildup may have fouled the sensor. The IACV is still the original one.

When I first started the motor, it was running on the stock P72 ECU parameters. No check engine lights ever. The new fast idle valve worked great quickly and smoothly bringing down the idle from 2000RPM to 800 RPM in a matter of a minute or so. I made sure there was no air in the cooling system. As it warmed up, the idle was smooth at about 750-800 RPM, I set timing to 16 degrees (I have a digital timing light). The coolant guage was steady at about 8 O'clock like it always was.

WIth only 38 miles on the new motor, I took it in for dyno testing yesterday and got it back today. The ECU has a new reprogrammed chip dropped in the socket. All the tweaks were done. I hit 180WHP at 7760 RPM and 130 lb/ft of torque at 5840 RPM. Both curves are very linear.

So now when the car is cold, the idle stays put at 2000 RPM for what seems like forever, or until the temp guage gets near 8 o'clock. The idle is surging back and forth from 800 RPM to 1200 RPM every few seconds. When the car is in motion, the temp guage reads really low........towards 7:00 o'clock. It only goes up when idling or no forward motion.

The dyno techs beleived that the surging idle could be my O2 sensor switching voltage too slowly because it could be fouled from oil buildup fromt he old motor.

So what do you all think? I can replace the O2 sensor, but what about the IACV? Is it OK to have a lower coolant temp? Will lower coolant temps cause idle problems?

 

Hmmmm. Interesting that no one gave this thread a shot yet. Perhaps it's too technical. Maybe if it was about fitting Type-R spoilers on DA's and HID kits you'd get some opinions.

You live in San Diego, yah? Is the climate there pretty tempurate? Curious. If it's relatively warm all year round, remove the IACV completely. If you still want to use it, simply remove it and take brake cleaner to the metal screen located on it. The screen will NOT come out, so just spray the whole thing down. Let it properly dry then reinstall. See if the problem persists.

While doing all that, re check all the grounds in the engine bay. Make sure there is good metal to metal contact.

It also wouldn't hurt to recheck your idle settings per HELMS specifications.

And since you've got the HELMS out, bust open the dizzy and check the primary and secondary coils along with a visual inspection of the cap and rotor.

 

i just dropped a gsr motor in my integra and i have the water run direct in the motor(not going inside the car to the heater) and i have a 2000rpm idle but my tps sensor is also out, but ive heard the low coolant temp gives high rpm...

 

Problem solved. The problem went away on its own. I think it was the throttle body. I had it sent out for rebuilding and boring to a taper bore of 67-64mm. I think that the throttle body butterfly was ever so slightly open, causing extra air to get into the manifold. But after several days of driving, I think the TB sort of 'broke in" and now the butterfly shuts all the way. My cold and warm idle is perfect now.

The moral of the story is that any extra UNMETERED air can cause the cool and warm idling problems that I described. Other causes are vacuum leaks, etc. Vacuum leaks can come from many places and the manifold connections and peripherals need to be looked at.