ASKED BY: ru4el4 0 0 0 5 1 2 48 ASK DATE: Jul. 25, 2005 CATEGORY: Mechanical | Engine Strange High Idle Share:       Vehicle: 1994 Ford Tempo I am checking out this Tempo. I checked codes for KOEO, no codes, KOER, 411, and 412, unable to control idle at either hi or lo limit. 1. Fuel press. was at 45 - 55 psi. ok 2. Tested MAF sensor, should be at 1 volt at idle, it was 2.013 volts. This goes down when I remove the air tube to sensor and Throttle body. 3. Tested Eng. coolant sensor and Air Charge Sensor; both seem to do their jobs. e.g. ohms changes when the temperature changes. According to the book, they are both fairly in range. 4.Checked timing, replaced Dist.cap, ign. wires, plugs and rotor. 5. Tried an engine relearn process; idle stay down for a while until I opened up the throttle! Then its high idle again!! 6. Checked for vacuum leaks, bad hoses, dirty throttle valves, bad battery connections and cleaned them!! 7. Checked problem at Idle air bypass valve. I replaced it. Resistance was 6 to 14 ohms. 8. I cleaned the ground wires and cables. I replaced PCV valve. COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Jul. 26, 1:06 AM QUALIFICATIONS: ASE Certified Site Rank: 1 Wow this one is very strange. It seems to me as though you have coverd most all of the appropriate bases for this problem. However i am eager to hear what others will come up with on this. COMMENT BY: HotRodKush 0 1 8 8 4 2 82 COMMENT DATE: Jul. 26, 7:14 AM QUALIFICATIONS: Site Rank: 3 could it be not an electrical problem, but simply dirt in the throttle body not allowing it to close fully? Just another area to look at. you also mentioned incorrect MAF reading - the sensor may be malfunctioning. Aaron COMMENT BY: DanD 0 1 5 7 7 0 86 COMMENT DATE: Jul. 26, 7:36 AM QUALIFICATIONS: Site Rank: 4 Does the idle drop when you unplug the IAC solenoid? What is the TPS return voltage at closed throttle, should be around .5 of a volt. Back probe the connector’s gray/white wire for your reading. You said there are no vacuum leaks have you checked the carbon canisters purge solenoid that it’s not stuck open? Other things to check are the power steering pressure switch and the AC pressure switch. If they are shorted the ECU maybe-getting signal to increase idle due to what it thinks is a load on the engine. Keep us up-dated. Dan. COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Jul. 26, 9:47 PM QUALIFICATIONS: Site Rank: 21 Hello again, Today, I broke out the Breakout Box to measure each of the voltages and test the circuits. With the engine running at the high idle, voltage sits at 11.4 v. When I open the throttle all the way the voltage drops to 8.0 v. I used Alldata info to check the ohms and continuity of MAF and IAC wiring. All ok. I did plug the Carbon Canister solenoid hose to see if it affected idle, no good. I recalled what a fellow mechanic told me about (hopefully) relearning the IAC, with the engine running, I WOT the engine and slowly let off of it. Surprisingly enough, this worked!! At least as long as you drive the car immediately afterwards. The idle is now down to 800 rpm. The engine is not overheating. When you turn the car off and later restart again you get the 2500 rpm again. I find that if I fast goose the throttle to the floor and release this brings it back to normal. Any ideas? Otherwise, I told my friend to follow this procedure to be able to drive this car without sucking up all the gas. I tried to substitute another IAC valve, but no good. I'm still looking. ACCEPTED ANSWER COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Jul. 27, 1:41 PM QUALIFICATIONS: ASE Certified Site Rank: 1 Sounds like the ECM may be the culprit if it is not staying with the relearn. COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Jul. 27, 9:59 PM QUALIFICATIONS: Site Rank: 21 Thank you for your response. Today, we tried disconnecting the A/c press. switch; no difference. I replaced the Throt. Pos. Sensor; no difference. Both old and new TPS gave the 1.021 volt. from signal wire. 5 volt reference was still good. We are still able to bring the idle down by WOT it. It drops from 2100 to 800 rpm. COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 4, 9:59 AM QUALIFICATIONS: Site Rank: 182 Hi guys, I just found you on google - I have a 1993 ford tempo dong exactly the same thing. I have replaced the TPS and checked and cleaned the Idle air bypass valve. Going to thoruoghly clean the throttle Body today. Please - anybody with a solution respond. Driving me crazy - I also hate to see a perfectly good car go bad because if I don't fix it soon it will. Thanks. Also - What are the steps in WOT the engine and what the heck does that stand for? COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 4, 2:59 PM QUALIFICATIONS: ASE Certified Site Rank: 1 Wide Open Throttle I what WOT stands for. COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 4, 6:01 PM QUALIFICATIONS: Site Rank: 182 Thanks for the info on that - I fiqured that out right soon after I wrote it - I have found a number of ford tempos that have had this fast idle problem but I have not heard from anybody that has fixed it. As is common on the internet as soon as somebody fiqures it out they don't respond any more. I really was thinking more along the lines of re-setting the computer - is it as simple as just disconnecting the battery - as that does not solve the problem? COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 4, 8:14 PM QUALIFICATIONS: ASE Certified Site Rank: 1 Well you probably won't find any good in a reset but you can try it. Have you checked for vacuum leaks. COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 5, 1:50 PM QUALIFICATIONS: Site Rank: 182 I have checked everywhere - cleaned throttle body - no help - when I block the by Idle Air pass valve the car dies - not getting any air then. It runs great, just won't idle down at all. It over heats if I am in any type of stop and go traffic. I was driving with my heater on today and I'm in South Carolina:) COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 5, 7:15 PM QUALIFICATIONS: ASE Certified Site Rank: 1 Have you checked the coolant temp sensor. This could cause both of these problems. COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Aug. 6, 1:09 AM QUALIFICATIONS: Site Rank: 21 To Jarrettbro, were you able to get any codes from the engine? One of the devices I use is a Sunpro Code reader for Fords. At the time I bought it, $35.00. Just plug it in the EEC-IV plugs and turn on the key for the Key On Engine Off test. Have a Chilton Total Car Care Manual or a Haynes Manual for your car. You may need to go online for the triple digit codes and their meanings. In the manuals, they show you how and where to hook up the tester. Also it will show you how to use a analog voltmeter to read the codes. Just count the needle sweeps. To Joe Allen, I have suggested the coolant temp sensor, to my friend. When I tested it, it did react in what seems the proper way to temperature changes. Ohms and voltage changing with temp. differences. Just for the [Edited] of it we will change it to see if it was a matter of calibration. What we do to drop the idle is quickly stomp the gas pedal and either slowly let off of it or quickly release it. This drops the idle on this vehicle. What we have discovered is the grommet, a nylon rubber donut that goes on the TV linkage to the transmission to help it shift, was gone. We replaced it. Trans. shifts better. When he drives the car now, after 3 or 5 minutes the idles drops down by itself. I would call this a slow relearn problem. COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Aug. 6, 9:35 AM QUALIFICATIONS: Site Rank: 21 I use carb. cleaner around the intake gaskets, vacuum hoses, and other upper engine parts to find vacuum leaks. It makes the engine run up the idle when a leak is detected. COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 6, 11:08 AM QUALIFICATIONS: Site Rank: 182 Just to sum everything up - When I say High idle I mean VERY VERY HIGH IDLE - THe hotter the engine gets the higher it goes. My rdiator fan works when it gets hot so I don't believe it is the coolant temp sensor. I did start gettting a trumpet sound a couple of months ago before this happened but could never find that problem. Throttle Valve is fully seated when at idle. My check engine light does Not come on. When I disconnect the IAC it did not react at all and when I took it out and started the car it was moving up and down freely as I had it connected. It ran almost the same with it off as it did with it on. But when I disconnect the MAF it does idle down but runs like crap, slows to almost diying and the surges up a bit and then repeats. I can not get it to idle down by WOT. I really find it hard to believe that I would have an air leak as it accelerates fine but it is slow to react when I take foot off gas. I am a lttle concerned about taking carb cleaner to it as if it idled any higher I think it might blow the motor. I did take a hose to it but couldn't find any leak. However I am still looking and it might very well be one some where. What would be some other symptons of an air leak besides just high idle? I have noticed the last couple of days it is now not shifting very well into third, it is an automatic, and down shifts a little unpredictable. I would think this is due to the confused state of the rpms but could there be an air line that goes to transmission that is leaking? Had autozone hook it up and could not find any codes. COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Aug. 6, 11:58 AM QUALIFICATIONS: Site Rank: 21 The one we have reacted the same way. It may be the Engine Control Module. ECM. Did Autozone use the OBD 1 tester? I know they can use the OBD 2 tester for the terminal under the dash, but the one I'm talking about is under the hood. Do the WOT very fast and all the way to the floor then release. If not that, then, do WOT very slow to the floor, then let off of it slowly in steps and see if that works for you. A seminar instructor for Ford Drivabillity Problems told us that there was a problem in the 1994 ECM units in a lot of the vehicle lines that Ford sold. Go to alldata.com to see if there are any bulletins on your year, make, and model. COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 6, 1:59 PM QUALIFICATIONS: ASE Certified Site Rank: 1 Good post ru4el4 COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 8, 9:07 AM QUALIFICATIONS: Site Rank: 182 Thnks guys! Got her fixed. The Idle Air Control valve aparently wears out over time even though it was clean and moving freely. I broke down and bought a new one just for the heck of it and it runs like a top. It was sort of odd because the one I purchased from Autozone went in sort of upside down with a jumper wire from the bottom to the top. It worked and if you see a great looking guy crusing around South Carolina in a red Ford tempo - it's me. Now what about that [Edited] A/C ......................? Thanks agian. COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 8, 12:55 PM QUALIFICATIONS: ASE Certified Site Rank: 1 If you want help with your a/c you will have to post a new question. COMMENT BY: RBHRacing 0 0 1 0 9 8 67 COMMENT DATE: Aug. 8, 3:43 PM QUALIFICATIONS: Site Rank: 13 I have a 93' probe in the shop right now, with the same problem. All the same tests and all the same answers. I'll keep you all updated. BTW new to the forums here. Tons of fun so far!!!! COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Aug. 8, 9:34 PM QUALIFICATIONS: Site Rank: 21 To Jarretbro, Where did you get the Idle Air Control valve? From Autozone or from the dealer, or other place? COMMENT BY: RBHRacing 0 0 1 0 9 8 67 COMMENT DATE: Aug. 9, 12:11 AM QUALIFICATIONS: Site Rank: 13 Just picked up a IAC/BPS($30) from salvage with 60,000 on it. Worked great. This explains the holding a rev issue as well. With increased engine RPM, a higher vacuum is created, which in turn could pull more air past the failing IAC plunger. One good thing I know for a fact that there is not a single leak ANYWHERE on the engine. Just got carried away with my own confidence in diagnostic stratagies. The IAC motor itself of course would test fine since the problem was manifested in a physical failure not an electrical one on an electronic component. COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 9, 2:52 AM QUALIFICATIONS: ASE Certified Site Rank: 1 Are you saying tht you got it fixed COMMENT BY: RBHRacing 0 0 1 0 9 8 67 COMMENT DATE: Aug. 9, 7:25 AM QUALIFICATIONS: Site Rank: 13 Yup, just took some out-of-the-box thinking I had ignored. COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 9, 11:00 AM QUALIFICATIONS: Site Rank: 182 I bought my IAC from autozone, Cost $75. Great forum guys! COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 10, 5:09 PM QUALIFICATIONS: ASE Certified Site Rank: 1 Thanks. COMMENT BY: ru4el4 0 0 0 5 1 2 48 COMMENT DATE: Aug. 18, 7:48 PM QUALIFICATIONS: Site Rank: 21 Well I am writing again to tell you what cured this particular problem. When my friend damaged his oil pan, we went to the junkyard to get another one. I then remembered what all of you said and decided to have him get an Idle bypass valve and a belt tensioner. The brand name that Autozone uses is Wells. I will not buy this brand ever again!!!!! I installed the used Idle Air Bypass. I put the new 4 week old Idle Bypass Valve from Autozone to the side. The car runs Beautifully!!!! It acted properly during all modes. No More WOT to bring down the idle. For a part like this, maybe, in spite of the price, you should get it from the dealership or the junkyard. Not from Autozone! COMMENT BY: jarrettbro 0 0 0 1 7 7 28 COMMENT DATE: Aug. 19, 9:58 AM QUALIFICATIONS: Site Rank: 182 I did notice that the one I purchased was odd - in the fact that it was upside down with a jumper from the botttom to the top for the wiring. It has been working freat so far - By the way my belt tensioner is rattaling - Can't I tighten that up or do you suggest womething else? COMMENT BY: joe allen 0 7 0 3 8 6 90 COMMENT DATE: Aug. 19, 1:26 PM QUALIFICATIONS: ASE Certified Site Rank: 1 I would just replace it. COMMENT BY: murphy318 0 0 0 1 1 1 27 COMMENT DATE: Nov. 4, 9:17 AM QUALIFICATIONS: Site Rank: 222 Comment:murphy318 Thanks for the info. my 1993 Topaz had a high idle 2500 r.p.m. You pointed me in the right direction. It didn't have an overheating problem. It was the i a c valve. Not that it didn't seat, it had cracks in the bellows surrounding the top spring causing too much air to circulate. I proved this by making a new gasket with only 2 , 1/4" holes instead of the 5/8" holes. It idled and drove normally. So I replaced it with a new valve. Thanks again for all the help Username: Password: Remember Me  Sign Up  Forgot Login? Year of 2009 way2old 3 Posts. 0 Answers. Mech Rep: 80 Mileage: 39920 swatkins 1 Posts. 0 Answers. Mech Rep: 74 Site Mileage: 5285 About Us | Contact Us | FAQ | Privacy Policy | Site Map Vehicle Aid © 2005-2008. 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