| Author |
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Ron (Rw229)
| | Posted on Tuesday, June 04, 2002 - 10:43 pm: | 
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'98 Disco w/ 52k has developed a rough idle and seems to be running way rich. Rich as in the tail pipe is black with carbon. If I clean it off, in 100 miles it's black again. I pulled a spark plug and it was also caked with carbon.
I run 93 octane and lead-foot often to try and blow it out. I also ran a bottle of some STP stuff through it that the dealer recommended, which didn't seem to make a difference.
Other than replacing the plugs and wires (both original) What else can I do to make it run cleaner/smoother? |
Mike Rupp (Mike_Rupp)
| | Posted on Tuesday, June 04, 2002 - 11:07 pm: |
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Might be an oxygen sensor. When they fail, the system defaults to rich.
Have you had the car emission tested? If it fails, it's a good sign that the O2 sensor is dead. |
Ron (Rw229)
| | Posted on Tuesday, June 04, 2002 - 11:20 pm: |
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Passed emissions 10/01. Is there a way I can test the sensor? |
JMcD
| | Posted on Wednesday, June 05, 2002 - 08:52 am: |
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Why don't you want to change the plugs and wires? Maybe I am missing something but it seems to me like your problem might be right there.
7year old plugs and wires are most likely causing some of the problems, maybe the cap and rotor are original too. Thats where I would start. Beyond that maybe the ects is bad. How is your gas mileage? The ects is about a $20 part. Start with the basics. Good Luck.
JMcD |
\Mike... (Mpeters)
| | Posted on Wednesday, June 05, 2002 - 01:44 pm: |
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You have several elements in this equation that could be a problem.. And most of them are a little costly to just replace, just in case..
Your MAS could be faulty I suppose, and certainly O2 sensors could be causing mixture probs. Failing fuel-pump can also mess with the mix, although that is more likely to cause lean conditions as it starts to fail.. you could have a leaky injector or two...
my point is - change plugs and wires - start there. Get a baseline for what your engine is doing AFTER that. Pull the plugs often to look for signs of moisture or carbon build-up. If you have an OBD reader, watch your trim readings to see you have an occasional problem or an intermittent problem... If you still feel you have a problem, start checking for vacuum leaks. You may find all the symptoms disappear with new plugs and wires. and definatley get aftermarket wires - OEM rover wires are crap. |
Ron (Rw229)
| | Posted on Wednesday, June 05, 2002 - 01:51 pm: |
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I re-read my post and it's a little misleading. What I meant to say is "in addition to" changing the plugs and wires. There is no cap and rotor, it has the GEMS.
What is the ECTS?
Gas milage is pretty good, 17mpg out of the last tank. (mostly interstate) |
Mike Rupp (Mike_Rupp)
| | Posted on Wednesday, June 05, 2002 - 05:46 pm: |
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Engine Coolant Temperature Sensor
Not sure, but if it isn't working the engine will run rich. |
JMcD
| | Posted on Thursday, June 06, 2002 - 08:04 am: |
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the ects is located at the right front corner of the engine, small sensor that threads into the manifold behind the thermostat. It senses the coolant temp and acts like a choke when the engine is cold, causing the mixture to be rich. If it is bad it could be causing a constant "cold start" mixture, ie rich. I read somewhere here what the resistance should be in Ohms but can't remember what it is. For the price I just swapped it out.
I thought your original post said it was a '95, sorry about bringing up the cap and rotor.
There are other possibilities as well, maybe bad fuel injectors, faulty MAF sensor, O2 sensors, etc. If you know how to use a meter try to test these different sensors and search for the proper resistance. Should be here somewhere.
Good Luck. JMcD |
Mike B.
| | Posted on Thursday, June 06, 2002 - 08:38 am: |
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In what book are the tests for all these sensors covered?
Thanks,
Mike B. |
Ron (Rw229)
| | Posted on Thursday, June 06, 2002 - 07:55 pm: |
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My plan of attack will be plugs and wires first since they're the originals. Then I'll move on to the sensors.
As above, what source/book has the tests for these sensors?
Speaking of sensors, I didn't think of this earlier, but around 10k ago, the dealer replaced the Y pipe due to a loose Cat. I don't know if they did the O2 sensors with it. Could there be a possiblity that the new Cat is messing with the old O2 sensors? |
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