Jrfish007

iTrader: (3)

Cold start sensor.... hummm..... I need to look some of these up.

Jrfish007

iTrader: (3)

checked your EGR valve lately? simple check and that can cause problems idle problems.... just guess though, I'm looking.

Jrfish007

iTrader: (3)

I think you need either a multi meter or handheld OBD II scanner, the later would be better. From there you can start scanning the values from these sensors and see if they are in normal range. I think streetglower has a HELM and can tell us the ranges for all the sensors. Really this sounds like your best bet to me.

gearbox

iTrader: (95)

well i do have a honda service manual i've been reading through. yea egr came to mind but its expensive to replace. I opened up the iac port (alot of people seem to have problems with the valves sticking) and sure enough its all dirty inside. Would it be safe to spray come carb cleaner in there? Btw i'm just practicing on a spare tb i got here. i was gonna send it to maxbore to get it cleaned and bored a few mm.

Jrfish007

iTrader: (3)

I've seen on some Ford trucks that the IAC sensor seal can be eaten away by carb/TB cleaner. better be careful with that stuff. I think most people just take the TB off, and use a soft toothbrush or something like that. I've heard of people using WD-40 to clean it, but that can eat certian plastics away too.

gearbox

iTrader: (95)

i'll do that with a rag then before sending it in. I wanna try the bored tb one more time cause i have a spare thats actually from an auto this time. What i can't understand is how well the car starts in warm weather. like today it was 65 and the start was perfect. I mean the three cranks, then very smooth vroom. no shakes or vibration. then it gets cold. it starts the first time, but once i leave the car for 30mins to a couple hours and try again, it bogs and almost stalls. thats why i wanted to know if we had a cold start sensor.

gearbox

iTrader: (95)

what about oxygen sensor?

Jrfish007

iTrader: (3)

Ehh... it may have a problem, but I'm doubtful that's the cause. This where a OBD II scanner would be usefull, you can plug it in and see what your O2 sensor is reading, look in the manual and see if that is within normal range.

Blackpearl

It was just one time thing (a trip to Nevadas ghost towns). I didn't travel after that on dirty roads.

gearbox

iTrader: (95)

what about map sensor. i guess i do need a scan tool but they're so expensive. still this could just be a cause of not enough backpressure. do you think a leaky exhaust mani gasket would cause it? still haven't had a chance to port and install a new one.

Blackpearl

I don't thik so. They operate only at high temperature. If that is bad, then you will have bad drive + bad milage when the engine is warm.

Blackpearl

You can rent OBD II scanner from Autozone for free. So you don't need to buy it. Did the check engine light come on?

gearbox

iTrader: (95)

it came on once when the idle really got rough and almost stalled but i didn't get a chance to read it before resetting the ecu.

Blackpearl

Well if the problem is there the light will come up again. There are error codes that will not bring the check engine light on if the problem is not persistent. So checking the cars ECU with scaner will help.

gearbox

iTrader: (95)

i don't think it will but maybe. the stock intake helped alot, and the drop isn't nearly as bad. you can tell its doing it, but not to the point where the car is shaking. i also know that the first 60-90 secs of a full cold start use startup fuel maps. after that (or when the car is not completely cooled off for warm start), it uses the sensors. this might explain why the it starts fine when cold but not after the car has been driven. maybe the sensors can't adjust to all the cold air rushing in as fast as it should whereas the startup map just runs very rich anyway so it doesn't matter with cold starts.

Jrfish007

iTrader: (3)

I talked to friend of mine thats a master mech, he said it sounds a iac sensor or a "fast idle thermo sensor." I've never heard of it, but it's simliar to the cold start sensor you where talking about. It is suppose speed the idle up depending on what how cold the engine is during start up, it's responsible for raising the RPM during cold starts. He isn't sure if the 7thgens have them or not, but his teg (and I guess mine too lol) has one. Check the helm and see if you can find it in there.

Jrfish007

iTrader: (3)

Well, if it only happened once, I wouldn't worry about it

Even if it something gone wrong, with it being able to reproduce it, a mechanic can not diagnose what they can not see. So unless it starts doing it more consistently, I wouldn't worry about it. If the roads where actually dirty, you may have just sucked in some exsive amount of dirt in the intake. You may want to check the air filter, and if that is good, just forget about it until it happens a more frequently or is at least reproducible.

gearbox

iTrader: (95)

yea we do have an IAC. thats the port on the side of the tb that lets air in the side of the tb. But i tested it according to the manual by putting my fingers over the port and the idle dropped almost to zero. so it works. plus if it didn't i'd have idle problems alot worse like when driving.

Blackpearl

I am not sure, but I heard (from one fiend) that there are two sensors in the intake. And they get dirty. They use some electrical cleaning spray. They cleaned the first one and the problem didn’t go away. They looked again and so another sensor close to that. They cleaned that and all was back to normal.

Jrfish007

iTrader: (3)

may want to check out the fast idle thermo sensor then, I think he said it was by part of the cooling system to measure temp, but they may have moved because of the ETC (sp?) sensor.

gearbox

iTrader: (95)

hmm i don't think we have one. the iac works like it by opening the port more. well this morning on a COLD start it was shaking but the rpm was at 1500 this time! So its not because the rpm is too low and stalling. After 5 seconds or so, it stabilized.

Jrfish007

iTrader: (3)

interesting............

what happens when you give it a little gas during the unstable period?

gearbox

iTrader: (95)

well usually before when i give it gas it just shook the car more and the rpm wouldn't go up very much. it felt like the timing was way off like when the distributor blows on older cars. now with the stock airbox, it usually doesn't last long enough for me to try and help it. after 5-10 secs it corrects itself and is fine after that.

gearbox

iTrader: (95)

heck ya finally the CEL is on!!!!

P0302 Cylinder 2 misfire detected

So far that tells me bad plugs (they are brand new) or bad ignition coil. What else would it be? The cam is advanced 2 degrees, but this problem was happening no matter where the timing was set. I'm looking in the service book now...

i guess it could also be caused by bad gas, dirty injectors (but i've been using fp60 for a few months now), bad ecu, or bad crank angle sensor.

gearbox

iTrader: (95)

or is it possible that the cam sensor that is now exposed (I took off the timing cover) is getting scrambled by the alternator currents? the exhaust can't cause a misfire can it? i'm gonna try switching the middle two coils and see what happens. Maybe its just a bad connection.

Sick Cycle

see? ... copper sucks.

haha jk. I'm sure you're torque-ing your plugs correctly, right?

are all of your grounds okay? do you still have the ground going to valve cover/head from the chassis?

gearbox

iTrader: (95)

haha yea it started before with the stock double plat plugs and has gotten 1/2 better when I put copper in. plugs are put on with a torque wrench to factory spec. I have all 3 stock grounds upgraded with 4 gauge cable all running to the battery negative. Thinking back, the problem really started for no reason. Two weeks after the exhaust/timing belt change I was fine. Its been happening lately when the weather dips below 60F, altho today was warmer and thats when the cel came on.

Jrfish007

iTrader: (3)

hummm.... I don't know eactly how the coils work on the d17's, but I remember working at the factory I used to work at, the coil packs for the ignition on the freezer unit that had engines on them would some times fail becuase the oil inside and water contamination. I guess if the oil gets hot enough, the oil mixes good with the water and the water isn't conductive, but when it was cold the water would seperate from the oil and short the coil. Could have happened not sure how though.

gearbox

iTrader: (95)

seems to be getting worse. its 68 degrees out and doing it every time i start the car. its still safe to drive slowly right?

tinman

No..... just do yourself a favor and scrap your car NOW while you still can.

Soo... shaking at start up for a few seconds. I had this exact symptom on my truck for a while, and only when cold. It turned out to be the choke not opening properly causing a way over rich mixture. This would clear up as soon as I hit the gas once or twice. Fixed the choke, and cold starts are fine.

So what valve acts as a choke on our civics? IAC comes to mind. Maybe it sticks a little when it's cold. It IS a mechanical, servo-driven valve....