'94 Ranger Help
Thread Starter
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
'94 Ranger Help
This is my first post in the Ranger series forum.
I have a 1994 Ranger ext cab with 127,000 miles. The motor is a 4.0L v6. When i first got the truck, it was running fine. After awhile, if you took a short drive and got the truck warmed up, shut her down and started it back up, she would idle real rough. Let it idle for a few, it would return to normal. Thing is, is it didnt do it all of the time. Sometimes it would start up fine... I have changed the plugs and replaced the filter with one from K&N. None of this helped so i pulled the codes. I got the following:
Codes of KOEO:
116-ECT out of self test range of 0.3 to 3.7 volts
114-ACT out of self test range of 0.3 to 3.7 volts
CM- 536- Brake On/Off circuit failure / switch not actuated during KOER test
CM- 543- When the PCM commanded the fuel pump on, voltage was not detected on FPM.
Not really sure on what to do with these codes, any ideas?
Also, i am getting around 15mpg in the city and 17 on the highway with 87 octane. Are these numbers about normal?
I have a 1994 Ranger ext cab with 127,000 miles. The motor is a 4.0L v6. When i first got the truck, it was running fine. After awhile, if you took a short drive and got the truck warmed up, shut her down and started it back up, she would idle real rough. Let it idle for a few, it would return to normal. Thing is, is it didnt do it all of the time. Sometimes it would start up fine... I have changed the plugs and replaced the filter with one from K&N. None of this helped so i pulled the codes. I got the following:
Codes of KOEO:
116-ECT out of self test range of 0.3 to 3.7 volts
114-ACT out of self test range of 0.3 to 3.7 volts
CM- 536- Brake On/Off circuit failure / switch not actuated during KOER test
CM- 543- When the PCM commanded the fuel pump on, voltage was not detected on FPM.
Not really sure on what to do with these codes, any ideas?
Also, i am getting around 15mpg in the city and 17 on the highway with 87 octane. Are these numbers about normal?
Elder User
Joined: Aug 2006
Posts: 761
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From: Southeast MI
543 has got to be the big issue here. Maybe a bad wire or something, esp under the big engine bay fuse box. 536, don't worry about it. It wanted you to hit the pedal at some point. Probably when the display or flashes showed code 10, which is not a trouble code. Then get rid of the K&N & put a non-oiled type in there before it coats the MAF elements in oily film.
Thread Starter
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
543 has got to be the big issue here. Maybe a bad wire or something, esp under the big engine bay fuse box. 536, don't worry about it. It wanted you to hit the pedal at some point. Probably when the display or flashes showed code 10, which is not a trouble code. Then get rid of the K&N & put a non-oiled type in there before it coats the MAF elements in oily film.
Elder User
Joined: Aug 2006
Posts: 761
Likes: 0
From: Southeast MI
I'm not sure. My truck had loose spade terminals to the fp relay. I squeezed them gently to a tighter fit after prying up the yellow cover under the relay. Beyond that, the rough idle sounds like an air intake issue if not fuel. Have you checked the MAF sensor? THey make a special cleaner for it that does a great job after you pull the whole MAF body out. Other things cause it too. How about the little sensor on the lower half of the airbox? ACT if I remember right. Then check for clean spark. I'm not sure beyond bad gas & fuel filter what else could cause these bugs at the moment without throwing codes.
Thread Starter
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
Would you recommend replacing this sensor, rather than testing it?
Junior User
Joined: Feb 2007
Posts: 81
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From: W. MI
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Post Fiend
Joined: Jan 2005
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Yeah, with running a K&N air filter, they have been known to contaminate the maff with oil. Mostly due to over oiling after cleaning. I stoped using K&N because in testing they let too much dirt through with all that extra flow and then there;s the oil issue on a ford maff. I now use the AEM dryflow, it flows and filters great and requires no oil. A good drop in filter that got high marks in testing was the aimsoil air filter. A lot of people stick with the stock paper filters, but it's hard for me to do as I know there restrictive, so it's a mental thing with me. I would try giving your maff a good cleaning.
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Elder User
Joined: Aug 2006
Posts: 761
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From: Southeast MI
The sensor is in a small aluminum tubular housing bolted to the airbox. You can get the special security style torx bits & pick plastic out of the screws or just pull the whole MAF tube & shoot the spray in just as easily.
Elder User
Joined: Jan 2006
Posts: 527
Likes: 1
From: Streamwood,IL
I used a small, and I mean small screwdriver to break the little tabs in those pesky screws (who cares,its outta warranty), and removed the MAF assembly..DO NOT put anything into and/or touch the element-use the spray you can buy at most parts stores..
Postmaster
Joined: Feb 2004
Posts: 2,595
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From: IL
You can use carb cleaner but as drb1956 stated don't touch the filament. I have the same year truck and motor. If this doesn't correct the problem try cleaning the IAC valve, if that doesn't fix it may need replaced. Without checking my log it seems I may have replaced mine about the same mileage. Check out the "tech thread" at the top of the Ranger forum, lots of helpful info, procedures, etc.
Good luck and welcome aboard the Ranger forum.
Good luck and welcome aboard the Ranger forum.