Idle Quality - Low To High When During Cold Temperatures

I will have to try to get some steel wool to get on the inside. I only have two steel brushes, which is what I used on those connectors.

I started the car after it sat four hours. 40 degrees out when I started it. The idled really high this time, to 2100, right after starting it. Got to the stop sign a block from my house, and it was at 2000. Half a mile down, it got back to normal at the stop light (1/3 of a mile down).

And, again, gauge slow to move.

Just find it interesting that behavior happened after I took the battery out and after cleaning those two ground wires on the side of the engine.

I need to find out where the other ground areas are so I can keep going on the checking and cleaning.

Also found this: http://toyota-solutions.blogspot.com/2011/02/got-p0171-blues-in-your-toyota-corolla.html

Also, there is a Felpro and a Beck/Arnley available at AAP. Do you recommend the Beck over Felpro? http://shop.advanceautoparts.com/web/PartSearchCmd?storeId=10151&catalogId=10051&pageId=partTypeList&suggestion=&actionSrc=Form&langId=-1&searchTerm=intake+manifold+gasket&vehicleIdSearch=49062&searchedFrom=header

RockAuto wants between $5.30 and $8.50 to ship a gasket, depending on brand. I can get the Fel-Pro at AAP and use a 30-percent off coupon

code.

I appreciate the help. I'm very serious about fixing this problem.

Beside a likely ground improvement, your ECU was also reset by disconnecting the battery.

I don't think there are more ground wires on your 2002.

I'd go with the Fel-Pro, even though they are probably both the same.

There has to be more ground wires, since you stated your ninth-generation has more ground areas.

LOL... Well, can you see any more ground wires?

Yours is just not grounded in the same manner as 9th gen Corolla. I also have the ground wire to top of tranny. My other ground wire from battery goes to chassis underneath battery. Your other battery ground wire is the one that goes to engine head, instead of having a seperate ground wire from head to chassis (inner fender).

By the way, I did upgrade all my stock ground wires to a larger gauge, and with a heavy duty solid battery ground connector. I also added a ground wire from existing grounding point on top of tranny to alternator, and another one from passenger side inner fender to front passenger side of engine head. It substantially improved low end response, and idle stability with A/C cycling on and off at windshield defrost setting.

Didn't last night, but since I also don't work Sundays, I'll look around more tonight. Nothing else to do because AAP doesn't have the gasket in stock, but they ordered it in and it will be at the store tomorrow.

How does additional grounding improve idle stability with the A/C cycling, and you stated at windshield defrost setting. What about just the regular setting without defrost? (I know A/C automatically engages in defrost mode).

I think there has to be a ground point in either the right or left front fender.

New ECT should arrive Thursday.

It's a custom ground upgrade I made, instead of getting a ground upgrade kit... With improved and better distributed grounding, idle speed is just more solid and less affected by the A/C pump cycling. There is also a noticeable improvement in low end tractability, torque, and overall smoothness of operation.

Yeah, without further investigating, I believe you should have an engine to chassis ground somewhere.

By the way, I also modified the cam behind vent control knob to have A/C cycling only from slightly clockwise of 'floor/windshield' setting instead of slightly clockwise of 'floor' setting, so that the A/C is not always cyling and wasting gas during winter when I usually have is at 'floor/windshield' setting.

Glad you brought that up. At what temperature (ambient) does it have to be before the A/C compressor will no engage?

Also, how do I go about finding the ground point on the chasis?

It is not temperature dependant. It is controlled by a switch that is activated by the cam behind vent control knob... It does not only defrost. It also defogs when humid as hell.

I've noticed if it's cold enough outside, the compressor does not engage. I assume this is to protect the system from freezing up.

I want to go back out to the garage to find that chasis ground point. Any ideas where I should look?

What about the other ground wire from battery terminal that is routed back on driver's side inner fender? Is it not bolted up to your driver's side inner fender? It would appear that it is your chassis ground which is ultimately combined with your other ground cables.

http://utoyot8.com/Picture.aspx?ccId=126042523&ppId=370674038&ppInfo=(9708-++++)&ccode=&ppName=

Also, where do the orange wires you cleaned at engine head lead to?

The orange wires I cleaned lead to the coolant temperature sensor area and then branch out in the direction of the battery.

Looks like I will have to remove fuse/relay boxes to check on the fender area...

Before I get started with the gasket removal, what do you suggest I use to scrap off the old material? I know aluminum is a soft metal, so I don't want to amake the mistake of gouging it. I do have razor blades, but is there a safer suggestion?

I still can't find a really good video of how to do it with this tubular intake. Is it just like the ninth-generation intakes?

Looking forward to this. It was back to idling high again tonight, and this time the temperature gauge took forever to get to the halfway point.

I assume I have to disconnect the upper radiator hose? Anything else I should be aware of?

33 degrees tonight.

Be ready for more photos after I can get a good video.

No need to disconnect any coolant hose, even on the TB which can be cleaned and set aside on top of tranny with the two coolant hoses still attached... I would probably use a blunt flexible scraper. Whatever you use, have it at a very low angle, without digging into the aluminum. Carefully slide on it at nearly the same angle as the surface you're cleaning. Finish with a green scrubbing pad used for dishes, along with warm water and dish cleaning detergent, or similar, then wipe it off.

If you have time and before you even try scrapping it, let it soak submerged in scolding hot water with dish detergent for a while, then use only the green scrubbing pad. Rinse out under running water, then wipe dry.

After removing manifold and before cleaning the head seating surface, carefully wipe out intake port inlets and stick a clean rag or paper towel tightly in each opening to keep any debris out... Remove just before reinstalling clean manifold with new gasket.

The two connectors with orange wires that you cleaned on driver's side of engine head should be your only existing engine grounding points. You also have a ground to starter, which is spliced from the ground on top of tranny, as seen on upper left of diagram.

http://utoyot8.com/Picture.aspx?ccId=126042523&ppId=370674038&ppInfo=(9708-++++)&ccode=&ppName

Found that ground point on the body (last photo). In the photo, it seems near impossible to get it out of there without draining the coolant and moving the radiator hose out of the way. I've taken photos of bolts I assume I have to remove, include the two down at the throttle body? Gasket comes in tomorrow, not today as the woman at AAP stated.

Yes, that's right about the bolts. You also need to disconnect vacuum and PCV hoses and sensors from the throttle body and unbolt it from manifold. You can also unbolt throttle cable holder from throttle body. End of throttle cable can be unhooked in wide open throttle position... It'll be more obvious as you go.

I see that body ground. You just need to remove the airbox to access it.

I figured it'd be more obvious. Tomorrow is the big day.

So, do you recommend I just drain the coolant and pull that upper coolant hose back to make it easier?

Update on another ECT sensor (same brand installed today): Now the needle on the gauge moves as it should -- quicker -- and in 42-degree weather.

However, with this sensor, the needle is a little above the halfway point.

Just shows each sensor usually yields either a slightly different result or a major difference.

Idle issue is still rather high when starting out (back up 2000 RPM).

Both sensors were installed after the ground point wires on the engine were cleaned using the wire brush.

Yes, I will have to take the air box off. Pretty easy.

Really looking forward to the Toyota sensor. I'd be surprised if nothing changes.

I would not bother with the coolant hose or with any coolant draining... I see now that it's hard to look behind 8th gen manifold flange to witness any signs of leaking.

Intake gasket looked great, looked just as good as the new one. Someone may have replaced it before I bought the car. Replaced it anyway. Did have to remove the upper coolant hose; there's no way to fully move the intake away unless the hose is gone. Reclaimed the coolant. Found another ground wire under the air filter box. Cleaned. Oh, and I noticed the VSV at the air filter box may have been disconnected for awhile. Perhaps this past summer? Maybe this caused the erratic and unusually high idle when cold out. I re-inserted it.

Did my best to clean the intake, but it's pretty bad. There is sand, oil and sludge. Not sure what in the hell the previous owner did. With all that sand, it's as if the car didn't have an air filter installed for awhile. I'm very surprised I am not burning more than 1/3 quart of oil every 3,000 miles, and surprised I don't have any lifter noise.

Update: no change in idle quality with VSV re-attached to air filter housing. With this ECT sensor, the idle is always at least 1100 RPM, even when gauge is mid-point at 53 degrees Fahrenheit. At a stop light, it does resort to 800 RPM within 20 seconds.

As originally stated, each ECT sensor yields different results.

The finger re-points to the ECT sensor.

I can see evidence of leaking at your old intake manifold gasket... How is it running now that the ECM had a chance to relearn the operating conditions?

No change at all.

However, as of two days ago, I hear a foghorn or like the sound of a smoke alarm beep (the tone) coming from the LF of the top of the valve cover. I thought it might be injector-related, so I unplugged the connector, but the noise remained.

All I did was take the old gasket off and put a new one on. Was I supposed to use a sealant? I'm wondering if there is a leak.

I paid on 11/07 for the ECT. However, they didn't ship it out until last Wednesday and I'm not expected to receive it until mid to late next week. They did give a 15-percent discount for the inconvenience.

Temps have been between 20 and 35 degrees. Doesn't idle wildly in the garage like it was, but still idles very high when I get to the stop sign after leaving home.

Just need to focus on this noise in the meantime. . .

Also, how many foot pounds should those manifold bolts be torqued to?