What would cause such a low idle upon start up when the engine it completely cold? In the mornings when I start up my car the idle is VERY low and it takes a long time (a few minutes) for the idle to notice that the engine is cold and raise the idle up. I am pretty sure the car should idle at around 2k RPM right away. My idle never even goes that high. During the first few minutes of the idle being low, if I give it too much gas it will eventually drop the idle low again and kill the engine. When I am backing out of my driveway in the first few minutes, I have to be careful not to give it too much gas. It is also around 15-25 degrees Fahrenheit outside currently. I don't remember this issue happening when I lived in warm Florida, but I could be wrong (this is my first winter up north).

Any help would be greatly appreciated. I have a 96 spec JDM B18C swapped into a 92 Civic hatch. The engine was just completely tuned up 2 months ago (plugs, wires, cap, rotor, fuel filter, new IACV, clean TB, new PCV valve).

 

same issue here. im throwing a p0172. bump for more info on the topic.

 

Sounds to me like you're having a timing issue. How exactly does the car idle after it's at normal operating temperature?

 

I love hybrid questions. What ECU are you running OP?

Ok, that's the extent of my help in this thread because we have no idea what else was done to that motor/car/wiring/sensors/whatever during the swap process.

If only there were a place for questions of this nature...

 

Yeah, but your car is OBD-II and the problem could be something completely different.

Usually this means the car is running too rich, correct?

Injectors, FPR, O2 sensors, etc. Could be a number of things. I believe I chased this code on a 2000 CRV I once owned.

And yeah, could be a timing belt slip as well.

 

Where does it idle, after it's completely warmed up?

 

sounds like i have my work cut out for me lol

 

noone wants to point out the obvious....i feel like a dick pointing it out so im not going to take it there...ill attempt being constructive for a change....was this an issue you were dealing with before said tune-up performed 2 months ago?

 

First off, I have had this swap for almost 4 years and this issue is something I just noticed because I moved to the north where I am currently experiencing below freezing temperatures. Before this, I lived in south Florida so I never took too much notice of my cold idle. I am sure it went up to near 2k RPM for a couple minutes.

I am running a P28 ECU with Hondata S300. The engine is completely stock, with bolt-ons and a tune that exploits those bolt-ons. I replaced almost all the internal seals/timing belt/water pump etc. when I got the swap and that was about 40k miles ago.

The idle is fine after warmed up. Solid 800-900 RPM I believe.

Mentioned tune up was done as part of preventative maintenance that I like to do every year or so. This is not showing a direct correlation with this idle problem.

Maybe my timing is off somehow? I last had my timing set when my car was dyno tuned with all the bolt-ons shortly after I performed the swap.

 

If it was tuned in S. FL, it was probably never tuned for cold weather. There is a setting where you can adjust the idle, timing, fuel, etc... based on the IAT. You may want someone to look into the S300 and see what those settings look like.

Craig - Who had to make adjustments his first winter away from Flordia

 

Hmm.. I would need to find someone who can tune Hondas in my area (often times this person is very shady, so I am not sure how to go about this).

I don't mess around too much in SManager.. don't want to mess up my current tune. I know how to adjust the idle, but that doesn't help much in this case because it does not idle where it says, when the engine is cold.

Who did your winter adjustments? (sucks leaving Florida!)

 

I have Neptune so it's probably different. There is a section that allows you to adjust percentages up and down on the fuel and timing map based on the IAT. You can also adjust the engine idle on IAT and coolant temp.

Craig - who still keeps the car registered in FL... no smog FTMFW

 

Easy, open up the idle tab. Go to temperature compensation and check the values entered. It happens a lot to have entered values for Celsius but the actual scale is in Fahrenheit. If it still idles low, adjust the IACV duty cycle to the right a notch. You can keep going and you will know it is at too high of a duty cycle when it rev hangs. SImply back it down one.

 

I agree with you, Craig. No smog ftw. I will be keeping this car registered in FL for a while.

FlewByU352, I will be checking out the tune in the next day or so when I get a chance. Is it okay to adjust the IACV duty cycle and look for rev hang even when the engine is cold? If so, what RPM level should be idle be while the car is still warming up in the morning?

(I notice you have a 352 in your username, do you live in Gainesville? I used to live there when I went to school there for 6 years)

 

You can adjust it when cold if you really have to, but it should be finalized when fully warmed up. That is when you will check for rev hang. As far as idle speed, I have mine around 1600RPM starting values at cold going to 950RPM when fully warmed up. Basically scale it across from one extreme to another. Also I live about an hour south of Gainesville.

 

mine runs fine in florida compared to being tuned in virginia...but if it were the opposite way around, tuned down here then up in virginia it wouldnt surprise me if it just needs to be re-tuned..

 

I need to check the table under temperature compensation. Did you say that a lot of times, the values are incorrect and should be changed?
I don't want to go to immediately adjusting my IACV duty cycle while the engine is fully warm because in that case, there will be no adjustment needed. The warm idle is perfect where it is.

 

Not trying to hijack the thread here. I took the car into RNZ here in San Diego for my idle problem. They found the issue in just a few minutes. My FPR needed to be adjusted. It was in fact running too rich and the issue is fixed. Thank you all for the advise and GOOD LUCK to the OP of the thread. I hope you get your car running right!