1994 Ford Ranger RPM Surges during driving erractically lik

Tiny
CAHOCA
  • MEMBER
  • 1994 FORD RANGER
  • 4 CYL
  • 2WD
  • MANUAL
  • 193,000 MILES
I have a 1994 Ford Ranger 4 cyl 5 speed Vin 1FTCR10A0RUD50946 While driving the throttle seems to get stuck and stays at a high rev. We have noticed it seems to be more often in damp weather. Spraying some fluid seems to help for a short while when sprayed on linkage, but always returns. We replaced the air filter recently and noticed screw gone around housing and fixed it. Seemed to run better for a while and back to the same old thing. Had a lot of people say it was the idle control valve. Replaced it today and also took carb cleaner and cleaned inside the throttle. Again, it seemed better more responsive and better power. Later in the day, happened 3 times within a mile. Each time my son would stop and spray the linkage and no success. We are about to look into the MAF but most posts don't associate problems like this with it. The throtlle linkage has been considered but since it is all sealed and nothing really exposed to corrode, felt it probably was not it but have gone no farther. Another suggestion was the throttle position sensor but that was replaced about 6 months ago when we were having starting problems. Mechanics have looked at it and don't have anything to add. I'd sure appreciate some help! Thanks in advance, Chuck
Tuesday, July 29th, 2008 AT 11:51 PM

7 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Since the IAC has been done it's either going to be the cable or the shaft in the throttle body, or the TPS, remove the cable, operate the throttle by hand, is it smooth, or does it have a noticable bad spot? Then do the same with the TPS. If throttle and TPS seem smooth, your cable may have a burr inside.
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Wednesday, July 30th, 2008 AT 2:28 AM
Tiny
CAHOCA
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We went through everything suggested and rechecked what we had done before. Also used white lub on inside of accelerator cable sheath to lube it. I noticed green build up inside 2 of the electrical connections so I disconnected the battery and tried to scrape as much off as possible and the followed with contact cleaner. Yesterday over about a 100 mile trip, the symptons did not show themselves except for a lower idle at times and a little rough idle periodically. Today however, the check engine light came on for 10 seconds and then went out. I'd go to Autozone to try and get the code read, but they told me before they don't have this special adapter for their meter that this engine requires. Should I be concerned. Does it indicate the MAF might still be going bad? Thanks Again
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Friday, August 1st, 2008 AT 3:40 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
2 things first what connector had the corroision, and that is what you scraped off? second on a 94 all you have to do is ground a connector, I am posting a picture for you. You then count the flashes and I will tell you what the codes are...OK?


https://www.2carpros.com/forum/automotive_pictures/62217_Test_Connector_Pre96_24.jpg



do this and count the flashes...Count the flashes, a 22 will flash as 2 flashes then a short pause, then 2 flashes, if more than one code is stored, the pause will be longer. The codes will display three times and end with 11 or 111. Write them down and post here. First do this with the ke on engine off, then again with it running.
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Friday, August 1st, 2008 AT 3:54 PM
Tiny
CAHOCA
  • MEMBER
  • 4 POSTS
I feel kind of stupid asking but I don't understand the drawing and how to do this. Not sure what a pigtail is and how to use it and where the probes of the voltmeter actually go.

The corrosion was on both plugs of the throttle position control and on both sides of the MAF plug in.

Thanks again
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Friday, August 1st, 2008 AT 10:32 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
You use either the voltmeter, or just put the jumper wire from the test lead to the top right lead of the diagnostic connector. Then turn your ignition to on, and count the flashes of the check engine light. If corrosion was found in TPS and MAF, you may need to replace both, and get a can of electrical parts cleaner and spray the connectors, then put some die electric grease in the socket, and reattach.
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Saturday, August 2nd, 2008 AT 6:21 AM
Tiny
CAHOCA
  • MEMBER
  • 4 POSTS
I got lucky and found an Autozone who had a flashing meter. Two codes that came out- #117 ECT SENSOR CIRCUIT BELOW MIN VOLTAGE OR 254 DEGREES AND #123 TP SENSOR CIRCUIT ABOVE MIN. VOLTAGE. He didn't seem to know what these indicated. I also put the ie electrical grease on both male and female plugs and sprayed with contact cleaner prior to doing that. Thanks again
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Monday, August 4th, 2008 AT 4:48 PM
Tiny
MERLIN2021
  • MECHANIC
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Now that the connections are cleaned, erase the codes and see if they come back, if they do, you need to est or replace the sensors or check the wires at both ends for condutivity. Start with the ECT if it's off it's like having a bad choke on a carbed engine, and might cause both codes.
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Tuesday, August 5th, 2008 AT 2:15 PM

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