95 3.8 manual 5 speed electrical problem - Ford Mustang Forum
 
LinkBack Thread Tools
post #1 of 6 (permalink) Old 12-06-2005 Thread Starter
Rookie
 
whimorris's Avatar
 
Joined: Mar 2005
Location: Mississauga, Ontario, Canada
Posts: 5
 
Question 95 3.8 manual 5 speed electrical problem

1995 Mustang 3.8 L V6 Manual 5 speed. Car starts, runs perfectly fine, no functional problem symptoms.

Interesting problem, apparently electrical, likely power/ground connection related. Suddenly while driving one evening, the speedometer stopped responding, then came back, (has operated normally ever since), Temp gauge became erratic, bouncing up and down, generally settling to a higher than normal reading, the speed of the Temp gauge excursions is such that it is impossible that the actual temperature could vary at that rate, physics being what it is... The temp sensor (on top of engine near thermostat) as well as the thermostat is new since this spring... wiring seems visibly intact to the sensor. After a day or so, the Service Engine light comes on. I do not have a code reader, but I expect it to be temp related.

Points of interest:
(1) increasing electrical load (turning on blower full, rear window defogger on) causes Temp gauge to move two letters higher, i.e. from A in NORMAL to hot line, back again when heavy load removed...
(2) turning ignition to start/crank position while running generally resets the Temp gauge to a more reasonable expected point, but this does not last, drift returns...
(3) when the ignition is switched off, the Temp gauge pegs clockwise to the 3 O'clock position (needle horizontal), a "feature" I do not recall seeing before.

I have rebuilt/tested the ignition switch, checked fuses in the engine compartment box, checked/cleaned battery terminals, ground connection from battery to engine, all fine. I have disconnected, disassembled/checked/reassembled the ECU, looks fine, no cold solder joints etc. I have removed/cleaned/tested/reassembled all instrument cluster connections, all OK.

I am in the process of measuring the actual engine temp during operation with an external sensor. This will tell me if engine temp is as it should be... (My assumption is that there is no physical temp problem)

Sadly, I have only a Haynes manual for this car. The electrical schematics are "generic" (generally useless, more block diagrams than schematics...) so I cannot trace wiring, the next logical step, in any efficient manner.

To anyone having any thoughts in this area, or any similar experience, your input would be appreciated. Also, anyone having elctrical wiring diagrams, Email scans/postings of these would be awesome...

Thanks, Ian

whimorris is offline  
Sponsored Links
Advertisement
 
post #2 of 6 (permalink) Old 12-06-2005
SHELBY GT 500 Member
V6 Member
 
kscoyote's Avatar
 
Joined: Aug 2002
Location: Topeka
Posts: 11,432
 
Quote:
Originally Posted by whimorris
1995 Mustang 3.8 L V6 Manual 5 speed. Car starts, runs perfectly fine, no functional problem symptoms.

Interesting problem, apparently electrical, likely power/ground connection related. Suddenly while driving one evening, the speedometer stopped responding, then came back, (has operated normally ever since), Temp gauge became erratic, bouncing up and down, generally settling to a higher than normal reading, the speed of the Temp gauge excursions is such that it is impossible that the actual temperature could vary at that rate, physics being what it is... The temp sensor (on top of engine near thermostat) as well as the thermostat is new since this spring... wiring seems visibly intact to the sensor. After a day or so, the Service Engine light comes on. I do not have a code reader, but I expect it to be temp related.

Points of interest:
(1) increasing electrical load (turning on blower full, rear window defogger on) causes Temp gauge to move two letters higher, i.e. from A in NORMAL to hot line, back again when heavy load removed...
(2) turning ignition to start/crank position while running generally resets the Temp gauge to a more reasonable expected point, but this does not last, drift returns...
(3) when the ignition is switched off, the Temp gauge pegs clockwise to the 3 O'clock position (needle horizontal), a "feature" I do not recall seeing before.

I have rebuilt/tested the ignition switch, checked fuses in the engine compartment box, checked/cleaned battery terminals, ground connection from battery to engine, all fine. I have disconnected, disassembled/checked/reassembled the ECU, looks fine, no cold solder joints etc. I have removed/cleaned/tested/reassembled all instrument cluster connections, all OK.

I am in the process of measuring the actual engine temp during operation with an external sensor. This will tell me if engine temp is as it should be... (My assumption is that there is no physical temp problem)

Sadly, I have only a Haynes manual for this car. The electrical schematics are "generic" (generally useless, more block diagrams than schematics...) so I cannot trace wiring, the next logical step, in any efficient manner.

To anyone having any thoughts in this area, or any similar experience, your input would be appreciated. Also, anyone having elctrical wiring diagrams, Email scans/postings of these would be awesome...

Thanks, Ian

you might send mustangtk a pm. He's a ford tech.


Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
kscoyote is offline  
post #3 of 6 (permalink) Old 12-06-2005
PONY Member
5.0L Member
 
wayne94mustang's Avatar
 
Joined: Jan 2005
Location: Hershy
Posts: 514
 
Send a message via MSN to wayne94mustang
my buddys 95 gt acted like that once but his radio even cut out. in his case it turned out to be the alt/voltage regulator...it was sending ether tomuch or not enuff current to the dash

94 gt aode baumannator,pi stallion 3000 stall,transgo,mega bite jrs,3.90 gears,31 spine moser axles,comp exteme,1.7 roller rockers,190 pump,mac cold air,ford 1 5/8 unequals, off road h,flowmaster 2 chamber with stainless tails,msd box,PIH(a9p computer ajustable fan controler),q1a k-member,kenny brown frame ties,driveshaft loop,air pump eliminator kit,bbk 70mm tb,pro-m bullit meter,24#injecters,ported heads&intake,and all the little bolt ons.
wayne94mustang is offline  
 
post #4 of 6 (permalink) Old 12-14-2005 Thread Starter
Rookie
 
whimorris's Avatar
 
Joined: Mar 2005
Location: Mississauga, Ontario, Canada
Posts: 5
 
Wink Problem solved

Turns out it was bad grounding from battery to body, several places. Gauge operation has returned to normal.

Now I find I have a failed O2 sensor "behind" the CAT (dealer's description ???)... I had to pay $105 CDN to discover this... (Local costs for an OBD II code reader average about $250 CDN) but the odd thing is, this failed O2 sensor does not seem to affect the car's performance at all, so I am going to leave it until I can scrape up more $$.

Anyone have any opinions on the wisdom of leaving the failed O2 sensor repair for a couple of months, assuming no performance degradation and realizing that I may burn out the CEL bulb...?
whimorris is offline  
post #5 of 6 (permalink) Old 12-14-2005
SHELBY GT 500 Member
V6 Member
 
kscoyote's Avatar
 
Joined: Aug 2002
Location: Topeka
Posts: 11,432
 
Quote:
Originally Posted by whimorris
Turns out it was bad grounding from battery to body, several places. Gauge operation has returned to normal.

Now I find I have a failed O2 sensor "behind" the CAT (dealer's description ???)... I had to pay $105 CDN to discover this... (Local costs for an OBD II code reader average about $250 CDN) but the odd thing is, this failed O2 sensor does not seem to affect the car's performance at all, so I am going to leave it until I can scrape up more $$.

Anyone have any opinions on the wisdom of leaving the failed O2 sensor repair for a couple of months, assuming no performance degradation and realizing that I may burn out the CEL bulb...?
I wouldn't worry about it. honda disconnected their O-sensors for years, to bump their reliability ratings.

The only problem is, if a real problem comes up, you won't know it, -but keep an eye on your guages, and your ears open, and you should be fine.

I drove a company car with the o-sensor cel light on for years.

Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17
kscoyote is offline  
post #6 of 6 (permalink) Old 12-14-2005 Thread Starter
Rookie
 
whimorris's Avatar
 
Joined: Mar 2005
Location: Mississauga, Ontario, Canada
Posts: 5
 
Wink Thanks

Thanks kscoyote, I appreciate the feedback.

I do intend to replace the silly thing, but I must get financially through the holidays - no mean feat... just finished putting tires on 3 vehicles including the Mustang, brakes on 2 of them... exhaust system on one...

Good thing I love Cars and Bikes

Have a pleasant holiday season,

Ian
whimorris is offline  
Sponsored Links
Advertisement
 
Closed Thread

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a VALID email address for yourself, otherwise you will not receive the necessary confirmation email needed to confirm, validate and activate your new AFM member account.

Failure to provide a VALID email address, will result in the cancellation of your new AFM member account registration.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
i need 3.8 95 owner manual pls on pdf yaser992002 V6 Talk 3 07-07-2005 04:46 PM
V-6 Manual Vert. on Speed Channel ponyman 2005-2010 Mustang Talk 0 01-23-2005 08:01 AM
5 speed-6 speed? Stillalive2029 2005-2010 Mustang Talk 5 01-09-2005 02:37 PM
How difficult to convert automatic to 5 speed manual transmission? popstick 4.6L Tech 7 08-19-2002 03:49 AM
2001 GT 5 speed pinging under hard throttle 11SecondT-Bird Mustang Tech 6 07-13-2002 01:13 AM

Posting Rules  
You may post new threads
You may 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 Off
Pingbacks are Off
Refbacks are On

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


Search Engine Friendly URLs by vBSEO 3.6.1