View Full Version : Weird Idle + Possible Overheating???

08-15-2008, 07:51 AM
Okay guys, back again! A few weeks/months ago I was finishing up the swap on a 5th Gen from a blown-up 4AFE to a low mileage 5AFE, some might have saw this, some might have not.
Anyways that's besides the point, the car is running now, and it runs fine, however, tonight I went to take my brother to work and when I dropped him off I finally noticed that the idle would go from about 1100 to 2400 and it would just go up, and drop, and up and drop and up and well, you get the picture. When I would put it into gear it would actually lurch forward until it hit 2400 and then lose power as it let the idle drop back down, then lurch forward again to 2400, all without input from the right foot.
So this is like crazy confusing, so I got home and popped the hood and looked under the hood for anything weird or out of place and I heard a clicking sound, like when your car gets hotter than it's supposed to, so I run back around to the door and lean in the window and see that my heat gauge is rising rather fast, it's about 2-3 notches below red, so I reach in real quick and switch off the car, it wasn't dropping fluid and from what I can see nothing was out of place, but it was dark and I'll check again tomorrow.
I've already done some trouble shooting but you guys got a lot better smarts than Google on this so I'm turning to this site for help, I've already looked into problems like the ISC valve, the radiator fan not working and a few other things, and it's not hard to pinpoint the overheating (brand new thermostat and seal, no leaking in the system whatsoever with brand new hoses all around, so it might just be low on fluid again or the fan didn't switch on, I forgot to check while it was running) but the idle is really kicking my ass. So any help would be incredibly appreciated, thanks guys,
- John

08-15-2008, 07:36 PM

Today I drove it again for a very short distance and when I got home I found my overheating problem; the hose connecting the water pump from the front to the back of the engine has a crack in it and is spilling all over the damn place, idle problem is still there, I don't think it's part of the heat problem. Help is still appreciated, I'm gonna check my idle screws and stuff before I get too incredibly in depth, thanks ahead of time.

08-17-2008, 10:12 AM
Seeing as there is a lovely amount of responses to this article I'll just put one last word in so if anyone who has the same problem happens to google it or something they can find some help.
I finally fixed the problem, I spent 1 1/2 hours going over every hose, vacuum line and w/e on the engine, finally working my way around to the trouble area. I noticed that the heater hose that runs from the water pump hose from front to back on the engine was actually coming off. I promptly readjusted the hose to where it was securely back over the fitting and put the clamp back on. After that I readjusted every hose that deals with the water pump in any-way and the did some other odds and ends (like putting on missing bolts off of the intake manifold support brace :eek: ), I traced the weird idle to the engine actually trying to compensate for the 3.5L of coolant that was lost out of that hose being loose by revving and getting the coolant to circulate. So everything is peachy dandy and then some on the car now and once again it's in perfect running condition.

I hope that whoever stumbles across this will get at least this much out of these three posts - never exclude anything in your search for what is wrong, go over it with a fine tooth comb before dropping $$$ for a part you might not even need.

08-17-2008, 05:17 PM
The idle wasn't from the lack of coolant, your ECU doesn't try to compensate for that [even newer cars with much more advanced ECUs don't do that]. :)

You most likely had a vacuum leak, maybe from not having the manifold stays on.

08-17-2008, 05:20 PM
Vacuum leak actually makes really good sense...I remember my mom's Honda Accord had a vacuum leak (really common with the 90-98 accords) and it would do that weird idle too...btw thanks for the reply, I was getting lonely XD

08-17-2008, 09:43 PM
sorry about your responses. ive had your idle problem too also due to a vacuum leak. just gota pop the hood and try to listen hard and find where it is leaking from. then i just replaced the hose.