Motor trouble 1996 cobra Excalibur 5.0

Dan 101662 · #1 (**permalink**) 05-01-2013, 06:54 PM

I have a 1996 Cobra Excalibur, 5.0 L engine. When I start it, sometimes it will run fine and other times the white dash light lights up, the engine runs very rough and rich. I use to be able to turn it off and start it back up just fine. Now the light is on continuously. I have changed the spark plugs, wires, fuel pressure regulator, and cleaned the mass air flow sensor with no success. Need help, anyone have any ideas?

FWB · #2 (**permalink**) 05-01-2013, 07:11 PM

Quote:

Originally Posted by Dan 101662

I have a 1996 Cobra Excalibur, 5.0 L engine. When I start it, sometimes it will run fine and other times the white dash light lights up, the engine runs very rough and rich. I use to be able to turn it off and start it back up just fine. Now the light is on continuously. I have changed the spark plugs, wires, fuel pressure regulator, and cleaned the mass air flow sensor with no success. Need help, anyone have any ideas?

factory ford FI and EEC IV?

if yes you will need to pull codes from computer.....

could be lots of things.....

Dan 101662 · #3 (**permalink**) 05-01-2013, 07:21 PM

It is a Cpu T4 MO, if you are asking for that. I put the code scanner on and it will not read any codes. It only has 24,000 miles on it . Any help would be appreciated.

FWB · #4 (**permalink**) 05-01-2013, 07:27 PM

doesn't make sense, if it's throwing a light, in essence thats a check engine light, there's a code there.
hell a bad sparkplug will throw a code.
rough and rich the computer thinks its lean adding more fuel....check the O2 sensors, i think theres more than one on that

Dan 101662 · #5 (**permalink**) 05-01-2013, 07:35 PM

I just got this car a week ago. There are 4 lights on the dash, the white one lights up. Do you know what that light is? All the spark plugs were wet so I changed them. It has 2 O2 sensors. From what I read, they only run when warm? The car is cold?

FWB · #6 (**permalink**) 05-01-2013, 07:41 PM

without being able to get a code i'm lost

cobraduke · #7 (**permalink**) 05-22-2013, 03:14 PM

Dan,
I found on my '96 that the diagnostic plug on the firewall had no connection to the computer. Tried to pull codes and got nothing. Sounds like that is what you may have going as well.

I was going to try tracking the pin connections to the plug, but never got to it. I was able to fix my problem without needing to read the computer. I didn't have a check light.

If your car is unmodified, the system is pure Ford so a cooperative, knowledgeable shop should be able to diagnose the problem and fix it. The computer is getting some sort of signal indicating it needs to add fuel (lean condition). If the engine is warmed up, the O2 sensors are a prime suspect. If it is happening cold, it could be air intake temp very low, coolant temp very high as just two examples. They may need to get the diagnostic port working first in order to get the info they need to isolate the issue.

Mike