OK, cooling issues seem to be taken care of. Next up, occasional high idle.

Occasionally, my car will idle high. It ONLY happens when warmed up, and usually after its been driven, parked, and then driven when still relatively warm but has cooled down somewhat. At some stops (clutch in) the rpms will climb from normal idle (about 800?) to between 1200 - 1500, although during these episodes the "lowest" high idle is 1000, and the highest its done it is 2000.

The "cure" is either a quick stab at the throttle, or to lift the gas pedal with my toe. Needless to say, its irritating, somewhat embarrassing (sitting at the drive through with the engine revving away till I can get it to calm down). It will not always do it, it will do it for a few stops in succession, and then will act normally again.

My guess is one of the 2 sensors attached to the throttle body. In fact I would lean toward the TPS.

Both sensors are riveted on, so removal (if needed) will be a pain.

Other useful information: Throttle cable tension appears to be ok, with a very slight amount of slack when at idle. When I move it by hand I can't feel any binding or sticking. Cruise control (factory equipped) switched on or off does not seem to make a difference if it will act up or not. Car was Seafoamed in spring. No CEL is ever triggered by this event.

Soooo fellow gearheads, I need some advice on troubleshooting and diagnosing. I have downloaded a manual as well as complete wiring diagrams for this car

Once again, 97 EX d16y7 (canadian spec). Basically a USDM DX, but with slightly different options. The only upgrade is a e-bay brand short-ram intake that I've had for a few years. Its not a new addition.

 

Sounds like the cable is getting stuck, or other mechanical problem with the throttle. Next time it happens, get out and pull the throttle lever on the throttle body, see if it was really fully closed. It probably wasn't. Check the return springs on the TB. You can also try adjusting the cable a little looser. Probably though you're going to need a new cable.

 

MK, setting the cable aside for a moment, any particular place I should look for "gunk" that could be restricting the throttle plate from returning to idle? (return springs, inside the throat, the throttle plate... anywhere else?)

probably wouldn't be a bad idea to totally remove the TB and give it a good scrub inside and out anyway, even if I need a new cable. thoughts?

 

Removing the TB and cleaning it out = good idea. On my previous 98 Civic and my current 99 when I bought them had sticking gas pedals, to the point where I could not take off from a light smoothly, and having to jam on the gas, and drop the clutch when the rpms were coming back down. Cleaned them out with brakleen/carb. cleaner, while scrubbing with a toothbrush and the sticking went away.

Everything that MK said is good, too. It could be the idle control screw, or the cable. I would try and clean it out first.

BTW, your technical help threads make it easy to help you since you actually give us all necessary information as well as previous work already done that is related to the issue at hand. You also make a point to state what year/trim/engine you have although it was stated in a different thread about a different issue, just to clear up any mis-communication as well as not making us go back and search for that info. Many others should take note. :thumbup:

 

LOL I post that stuff so the thread isn't full of "what year" "what happened?" "what trim" "any work done previous" etc... if I was paying a mechanic I'd want him to have all the details rather then try to figure out the stuff himself. Some of it might not be relevant, but some of it might offer clues.

Glad to be on the boards here though, I help where I can

This week sometime I'll probably yank the TB and give it a good bath. Is Brake Clean safe for the sensors or should I just stick with Throttle Body/Carb cleaner? (I assume it is but I'd rather find out the easy way then the hard way!)

 

Remove the MAP sensor (if your Canada version has it on the throttle body) before dousing the throttle body with cleaner. Be sure not to lose the o-ring under the sensor. Try to keep solvent off of the TPS as much as you can. When reinstalling the throttle body be sure the gasket seals OK. Air leaks will cause a fast idle.

 

Thanks MK. like I said. I'll probably do that this week and will report back (hopefully with an improvement. If not, next step will the throttle cable - although now that I think about it its probably still the original one. I'm currently at 222,000km (138,00 miles) so it probably needs to get replaced soon anyway