Wiring harness replacement question

faststang90 · 02-11-2002, 08:40 PM

i put a new wiring harness on my car not the same but it all i could get the car will start and run as long as u have the key turned to start but when u let go the car dies in the run spot
can any1 help fix this

84LX89GT · 02-12-2002, 01:57 AM

well without any specific information, it seems your processor isn't getting correct inputs (assuming all the hardware and sensors are ok). So basically, you'll need the correct harness for your vehicle.....not a whole lot you can do unless you want to rewire most of the engine sensors, in which case you may want to get a Ford EVTM (Electrical and Vacuum troubleshooting manual), and shop manual, and PCED (Powertrain Control and Emissions Diagnostic manual). This would cost alot of money......which would be better spent on the correct harness.

By the way, why did you replace your harness and what did you replace it with.

faststang90 · 02-12-2002, 09:06 AM

i replced it with m 12071-c 302 the reason y i did was that i was not getting a tps reading with the other harness it was reading but it was 4.95 volts all the time

DRASTiK · 02-12-2002, 10:38 AM

FastStang90,
At one time, I had the same problem with my TPS reading, along with a few more electrical problems. My fix was to replace the EEC. You can check your harness by using the wiring diagram in the back of a Haynes book for your car. Hopefully your fix is a cheaper one.

Dave

PKRWUD · 02-15-2002, 04:04 AM

Couple questions:

How did you determine it was the harness that was at fault? What does the TPS test at with the new harness? Have you verified that the problem is not with the ignition switch? You can try running a hot lead to the coil pos. terminal, and after starting it, see if it goes into closed loop.

Fostang · 02-15-2002, 05:35 PM

The problem sounds like the eec is getting its power from a different part of the ignition switch. Ignition switches have three different outputs. (1)acc (2)run 3(start) find a book on the wiring harness that you have and redirect the wire that feeds power to the ecc correctly into the run position.

faststang90 · 02-16-2002, 12:53 AM

i did my taxs the other day im getting back some good money back so im going to get a dfi in a few weeks so that problem should go away

k. putman · 02-16-2002, 08:57 AM

Check the ignition cylinder as well. The rental fleet I manage has had several Taurus/Sable, Explorer, F150 cylinder failures resulting in the condition you described. While it would be very odd that a failure occured at the time of harness replacement, it might be something to check. (This happens as well to Honda's...that have a heavy set of keys hanging in the switch).

02-11-2002, 08:40 PM	#1
faststang90 Registered Member Join Date: May 2001 Location: baytown,tx,us Posts: 128	Wiring harness replacement question i put a new wiring harness on my car not the same but it all i could get the car will start and run as long as u have the key turned to start but when u let go the car dies in the run spot can any1 help fix this

02-12-2002, 01:57 AM	#2
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	well without any specific information, it seems your processor isn't getting correct inputs (assuming all the hardware and sensors are ok). So basically, you'll need the correct harness for your vehicle.....not a whole lot you can do unless you want to rewire most of the engine sensors, in which case you may want to get a Ford EVTM (Electrical and Vacuum troubleshooting manual), and shop manual, and PCED (Powertrain Control and Emissions Diagnostic manual). This would cost alot of money......which would be better spent on the correct harness. By the way, why did you replace your harness and what did you replace it with. __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

02-15-2002, 04:04 AM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Couple questions: How did you determine it was the harness that was at fault? What does the TPS test at with the new harness? Have you verified that the problem is not with the ignition switch? You can try running a hot lead to the coil pos. terminal, and after starting it, see if it goes into closed loop. __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

02-15-2002, 05:35 PM	#6
Fostang Registered Member Join Date: Feb 2001 Location: Stockton, Ca Posts: 599	The problem sounds like the eec is getting its power from a different part of the ignition switch. Ignition switches have three different outputs. (1)acc (2)run 3(start) find a book on the wiring harness that you have and redirect the wire that feeds power to the ecc correctly into the run position. __________________ 67' Fastback-Supercharged 4.6 DOHC Cobra, T-56, 8.8 more to come. 67' Coupe-EFI, AOD, 8.8 90 Gt-Supercharged,MAF,TB,1.7's ripper, bassani x, 3.55's, 01' cobras, headers. 89'GT-Supercharged,Heads,Cam,Intake,TB,MAF,power pipe,headers,offroad exhaust,black bullits.

02-16-2002, 12:53 AM	#7
faststang90 Registered Member Join Date: May 2001 Location: baytown,tx,us Posts: 128	dfi fix i did my taxs the other day im getting back some good money back so im going to get a dfi in a few weeks so that problem should go away

02-12-2002, 09:06 AM	#3
faststang90 Registered Member Join Date: May 2001 Location: baytown,tx,us Posts: 128	i replced it with m 12071-c 302 the reason y i did was that i was not getting a tps reading with the other harness it was reading but it was 4.95 volts all the time

02-12-2002, 10:38 AM	#4
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	FastStang90, At one time, I had the same problem with my TPS reading, along with a few more electrical problems. My fix was to replace the EEC. You can check your harness by using the wiring diagram in the back of a Haynes book for your car. Hopefully your fix is a cheaper one. Dave

02-16-2002, 08:57 AM	#8
k. putman Registered Member Join Date: Oct 2000 Location: Homewood, AL Posts: 30	Check the ignition cylinder as well. The rental fleet I manage has had several Taurus/Sable, Explorer, F150 cylinder failures resulting in the condition you described. While it would be very odd that a failure occured at the time of harness replacement, it might be something to check. (This happens as well to Honda's...that have a heavy set of keys hanging in the switch).

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