Strange problem on '95 Fairmont (EF engine) - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 04-26-17, 08:14 AM Thread Starter
Registered User
 
Join Date: Apr 2017
Posts: 4
Strange problem on '95 Fairmont (EF engine)

My 1995 Fairmont will intermittently cut out while driving. This usually happens when the engine is at operating temp and after a short stop (like quickly stopping at the shop to buy milk or something). It also normally happens shortly after driving off while the speed is still slow. If I try to restart, the engine will start but it runs very rough (actually sputters) and cut out again. This is when I start it from the On position on the ignition. Only if I turn the key in the ignition all the way to Off, and start it then, will it start normally and run as if nothing is wrong.

I pulled the error codes and it does not report anything wrong, except code 126 which is MAP sensor out of range. I recently replaced the MAP sensor with a new one and I doubt that it could be the problem. The previous MAP sensor was faulty and I had almost no power, the engine was running rich the whole time, and I only got 5 km to the litre (20 litre per 100km) on the open road. Since replacing the MAP sensor, the power is great, and fuel consumption is now 10km to the litre (10 litre per 100km) on the open road.

Before the MAP sensor replacement, the car did not cut out like it does now. This only started after the MAP sensor replacement.

Any ideas what may be the problem?

Sjarko is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 04-26-17, 04:40 PM
Moderators
 
Join Date: Feb 2001
Location: Bibra Lake Western Australia
Posts: 3,302
Re: Strange problem on '95 Fairmont (EF engine)

It will be the MAP sensor or possibly the wiring to it. The stalling is consistent with a faulty MAP sensor (for example http://www.autotap.com/techlibrary/s...g_problems.asp for example) and diagnostic codes are usually correct. If it's a new rather than used MAP sensor, and you cleared the codes before or after replacing it is likely the wiring to the sensor or a leak in the hose to the sensor (or the hose is disconnected at one end).

Regards Blue
Aussiblue is offline  
post #3 of 9 (permalink) Old 04-26-17, 04:52 PM
Moderators
 
Join Date: Feb 2001
Location: Bibra Lake Western Australia
Posts: 3,302
Re: Strange problem on '95 Fairmont (EF engine)

Also check the small plastic vacuum line elbow that screws into the inlet manifold immediately below the throttle body is not cracked or broken as the often crack or break and a vacuum leak there will also adversely effect the performance of the MAP sensor.

Regards Blue
Aussiblue is offline  
 
post #4 of 9 (permalink) Old 04-26-17, 05:21 PM
Moderators
 
Join Date: Feb 2001
Location: Bibra Lake Western Australia
Posts: 3,302
Re: Strange problem on '95 Fairmont (EF engine)

To check the wiring with the ignition switch off disconnect the harness plug from the MAP sensor. Then turn the ignition on and check for voltage at the orange black wire of the wiring harness plug (should be between 4 and 6 Volts). If 0 volts check for a blown fuse (remove fuse and check for continuity with a multimeter; don't just visually check). With ignition off also check for continuity between the centre wire of the plug and pin 34 of the ECU. Then check for continuity between earth and the third wire on the plug. Next reconnect the wiring harness and back probe the MAP sensor plug at the centre pin while it is connected to the sensor and use an oscilloscope, frequency meter or a multimeter with a frequency setting. The readings at sea level should be:

Ignition on 0.155 to 0.156 kHz
Engine idling in neutral 0.101 to 0.103 kHz
Engine revving in neutral 0.90 kHz
Engine Idling in Drive 0.105 0.106 kHz
Engine Idling in Drive Air Con on or Power Steering in use 10109 to 0.111 kHz

If you don't have something that can read frequencies but have a multimeter with a tacho function (or have a hand held tacho) set it to the 6 cylinder range and connect it by back probing between the black/white signal wire and the blue/yellow return wire. With the vacuum hose disconnected from the sensor it should read 300 to 320 rpm. If you apply 68 kPa of vacuum to the sensor vacuum port the tacho reading should change to 200 to 230 rpm with a smooth (not immediate) change between the with and without vacuum reading.

Regards Blue
Aussiblue is offline  
post #5 of 9 (permalink) Old 04-26-17, 05:22 PM
Moderators
 
Join Date: Feb 2001
Location: Bibra Lake Western Australia
Posts: 3,302
Re: Strange problem on '95 Fairmont (EF engine)

BTW I am assuming this a straight 6 not a V8.

Regards Blue
Aussiblue is offline  
post #6 of 9 (permalink) Old 04-26-17, 09:31 PM Thread Starter
Registered User
 
Join Date: Apr 2017
Posts: 4
Wink Re: Strange problem on '95 Fairmont (EF engine)

Thank you very much Aussiblue. Yes it is the straight 6. I will do these checks.
Sjarko is offline  
post #7 of 9 (permalink) Old 04-28-17, 06:54 AM Thread Starter
Registered User
 
Join Date: Apr 2017
Posts: 4
confused Re: Strange problem on '95 Fairmont (EF engine)

I have not tested the MAP sensor yet, but I cleared the error codes and drove around town. I had the same issues again (as per the details below). Afterwards, I pulled the error codes again in KOEO and KOER and it gave my no error codes at all. Now for the problems I encountered:

Although it did not actually cut out, there were a few times it stumbled when trying to pull away at stops, traffic lights, etc. To prevent it from stalling, I have to completely take my foot off the accelerator, let i slowly start to move under idling, and then very very slowly start to use the accelerator. My previous experience was that any attempt to accelerate normally will definitely make it stall.

While this is happening, I have to smile and wave to all the nice people in the car behind me giving me middle finger greetings.

After about 10-15 seconds of feather footing the accelerator, it will come right and drive normally. Although I will test the MAP sensor, I do not think it is the problem as it is brand new and was installed by a qualified auto-electrician that checked the wiring and connector plug as well.

Can it maybe be the coil pack/leads or TPS ? Any suggestions will be very welcome.
Sjarko is offline  
post #8 of 9 (permalink) Old 04-28-17, 06:58 AM Thread Starter
Registered User
 
Join Date: Apr 2017
Posts: 4
Wink Re: Strange problem on '95 Fairmont (EF engine)

Quote:
Originally Posted by Aussiblue View Post
BTW I am assuming this a straight 6 not a V8.
Yes. Straight 6. Thanks for your help Aussiblue.
Sjarko is offline  
post #9 of 9 (permalink) Old 04-28-17, 03:42 PM
Moderators
 
Join Date: Feb 2001
Location: Bibra Lake Western Australia
Posts: 3,302
Re: Strange problem on '95 Fairmont (EF engine)

You may have a vacuum leak at the inlet manifold that closes up when the manifold gets hot. They usually at number 1 and/or 6 and at the bottom of the manifold where the manifold joins the head. They leak because the nuts get loose with time and the gasket partially burns out. You won't find these leaks by spraying engine start, oil, butane gas etc around the manifold because the leak is so small and at the bottom so gravity stops things being sucked in. Even smoke tests don't work well. You need to get a metre or so of windscreen washer sized tubing and stick one end in your ear while moving the other end around the inlet manifold especially at the bottom of cylinders 1 and 6. Do this with the engine idling and try it with a cold and hot engine; if there is a leak you will hear the distinctive sucking noise through the tube.

If the stalling happens on slow (and even slight) turns rather moving straight ahead then the power steering switch, that up the engine revs to counter the power steering load, may have failed or become unplugged.

Also check that plastic vacuum tube elbow immediately below the throttle body.

Regards Blue
Aussiblue is offline  
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > Australian Ford's Discussion > E-Series Falcons


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome