Temp. sensitive MIL???

[Carlos]

Tricky one:
For about a couple of days of 40-60 degree temps and lots and lots of dense morning fog. Every time I drive my Disco ll, the MIL lights-up. I start the truck, let it idle for about 10 min until it warms-up, no MIL so far, but after driving for approx. 20 min in lower temps. (40-60 degrees) and through dense fog, the MIL shows-up. If I disconnect the battery and let it sit for a while, when I start the truck again, the light goes on and then shuts off as normal. if I don't go through the conditions listed before, no light shows up for days. Any clue? Haven't pulled the codes yet.
background/history: '99 Disco, 120K, new MAS 5 months ago by LR Cary, new O2 sensors a year ago, new cat "y" pipe a year ago... yes, around $1,500 spent.

Thanks,
Carlos

[Disco Mike]

Slow morning for me Carlos, when you say Mil light what light are you refering to.
Also, don't let you Disco run for 10 minutes before driving, 30 seconds and go other wise all you are doing is burning lots of gas and making dirty oil.
Mike

[Carlos]

Sorry Mike:
"Service Engine Soon"-SES light or "Malfunction Indicator Light"-MIL light

Carlos

[Disco Mike]

I wasn't sure that is what you were refering to.
Have you scanned for codes, if not that should be the next thing to do.
Living in Colorado my 99 fires right up and is rolling in 30 seconds, I have never experienced a moisture or high humidity problem and without codes, the only thing I can think would be a dirty or loss connection or ground.
Let me know what you find.
Mike

[Rovin4life]

disconnecting the battery does nothing.


Gets the codes and you can begin to diag the vehicle.

IT could be anything. Even the thermostat. If it is slow to heat it will throw a code.


Especially after idling.

[Disco Mike]

Carlos, how is the truck, what did you find wrong?
Mike

[Carlos]

Well Mike:
After a noticeable temp increase around here, just disconnected the battery the day before yesterday, had it sit overnight, connected it yesterday, let the truck sit one more day (used wife's car), and today I went to fill her up with gas, and when I cranked it up, I noticed the battery a little hesitant with a slower turning starter(it took kind of more than normal engine turns to start, but it did) and no service lights on. I wonder if the battery might be going out(it has more than 2 yrs.), and the lack of energy might be triggering the light. When I drove, as previusly said, under lower outside temps. and dense fog, the light came on after pushing the accelerator, i.e. to pass/overcome other cars on the highway.
Also, my neagtive battery terminal is lackin the tightening bolt with the particular-shapednut, so I just push it in. I will post an ad here in order to see if someone has one of these hanging around with no use for it. Anyways, I'll be figuring this out after the holidays, as today I'm traveling to Texas to see my parents and spend the Holidays with them.

Thanks and Happy Holidays to all,
Carlos

[Disco Mike]

Have a good Christmas in Texas.
By the way, you shouldn't unhook the battery to try and clear a problem. D2's will loose the memory in the ECU and it takes sometime for them to relearn and in the mean time it will effect your MPG, power and shifting.
Mike

[Carlos]

Well, the light came back on today. I'll probably take it tomorrow to Autozone to pull the codes. Does anybody know if they'll do it for free or how much do they charge for that?

Carlos

[Disco Mike]

In most areas, they do it for free, what they may not do is clear the codes.
I am curious as to what is causing your problem, here in Denver we have been having temps in the teens in the morning and I haven't had this happen so if you could get back to us with the fault codes numbers, that would be great.
Mike

[Dan Erickson]

Originally Posted by Disco Mike

Have a good Christmas in Texas.
By the way, you shouldn't unhook the battery to try and clear a problem. D2's will loose the memory in the ECU and it takes sometime for them to relearn and in the mean time it will effect your MPG, power and shifting.
Mike

???

Mike, I was under the impression that disconnecting the battery would have no effect on the ECU memory, hence the reason why the fault codes can't be cleared using this method.

Carlos,

X2 on what Mike said about Autozone. In my experience, they have read the codes for free, but will not reset them (the guy said for liability reasons). I have heard only a few stories where they have reset the codes.

You can get your own code reader for dead cheap these days. It may be a wise investment. Although it was a bit more expensive, I just picked up a Scangauge II (http://www.scangauge.com/) for about $170 shipped. I really got it for my other car, but it works with the Rover as well. It will read and clear codes and much more like real time data and gauge display of various systems.

I remember my first winter with my D2. Driving up North in very cold conditions, my SES light went off. I'm trying to remember the code, but I think one of them was something like adaptive value out of range (or something like that). I can look the exact code up later as I saved it using the Rovacom.

The point I'm trying to make, is that my MAF was going bad, and the cold air entering seemed to exaggerate/manifest the problem.

I'm not saying this is your problem (especially since you mentioned in you first post that you recently replaced the MAF), just something to think about.

You don't have a K&N air filter do you?

Peace,

Dan

[Carlos]

Hi Mike:
Pulled the codes from Auto Zone. There were three of them and seem related to each other. Here they are:
1. p0300 = Multi-cylinder misfire
2. p0305 = Cylinder #5 misfire
3. p0308 = Cylinder #8 misfire

The person there asked me when was the last tune-up for the truck. The plugs were replaced around Nov. 2005 with Bosch platinum +2, but honestly the truck has 120K miles and I've never changed the plug wires.

Thanks,
Carlos

[Disco Mike]

Originally Posted by Carlos

Hi Mike:
Pulled the codes from Auto Zone. There were three of them and seem related to each other. Here they are:
1. p0300 = Multi-cylinder misfire
2. p0305 = Cylinder #5 misfire
3. p0308 = Cylinder #8 misfire

The person there asked me when was the last tune-up for the truck. The plugs were replaced around Nov. 2005 with Bosch platinum +2, but honestly the truck has 120K miles and I've never changed the plug wires.

Thanks,
Carlos

Bingo!!
That sort of mileage will kill even the best of wires.
Might want to consider a set of Magnacor 8mm wires.
Alos at your mileage, your O2's are starting to hold back both your power and MPG.
Mike

[Carlos]

Mike, forgot to tell you a little service history on the truck:

1. New Mass airflow sensor last summer.
2. New cat converter "Y" pipe form Atlantic British about a year ago.
3. New all 4 O2 sensors about a year ago too.
Plus the mentioned Bosch plugs.

Do you think I might need to buy new plugs again too ???

Carlos

[Disco Mike]

No, you should be fine, but I would run a bottle of SeaFoam thru the gas tank just to clean up the plugs alittle.
Mike