Idle too high

[knewsom]

Hi folks, just joined the LR club, bought a '99 Disco Series I 4.0.

Here's the issue - K&N filter in the airbox, removed and cleaned (was FILTHY FILTHY FILTHY), and wiped down the inside and outside of the airbox with a moist microfiber rag. Re-oiled K&N filter, installed it (everything's dry, no moisture), now my idle is 1250 instead of 750.

Supposedly there's no standard idle adjustment on a land rover and that's done eletronically...!? Is there something I need to reset, or replace to fix my idle? I'm pretty sure I'm going to have to smog it, and there's no way it'll pass idling like it is.

Any help would be much appreciated, sorry for the long post.

-K

 

[ptschram]

The adaptive values in the engine ECU can be reset to bring the idle back into spec. There may have been enough restriction through the filter that the ECU was compensating for it and when you cleaned the filter, the airflow was enough greater that it resulted in the high idle.

BTW-get rid of the K&N, there are many rumors of them causing failures of MAF sensors.

Welcome to the cult!

 

[knewsom]

BTW-get rid of the K&N, there are many rumors of them causing failures of MAF sensors.

Huh, that's odd, you think it's just too much airflow for it to handle? Or could it be something to do with the oil on the air filter? Weird, I was all stoked on that K&N too... Guess it's back to plain 'ol paper.

How exactly do I reset the ECU? Thanks for your help, and the kind welcome!

-K

 

[btp98w]

It's the oil from the filter ruining the MAFS. Just stick with the oem filter.

 

[gmookher]

how does one clear adaptive values without testbook?

 

[knewsom]

would disconnecting the battery for awhile work?

 

[ptschram]

would disconnecting the battery for awhile work?

No. Well,. it might, but I don't know how consistently this will work,

 

[knewsom]

so basically, this is something I'll have to take it in for.

 

[ptschram]

Or find someone with a computer that will do it.

DEC, Autologic, Rovacom, etc.

 

[knewsom]

ahhh crap. any reccomendations for the LA area?

 

[knewsom]

quick update: contacted local british mechanic (LR certified), he says the oil from the filter probably contaminated the MAFS, to fix, simply take it out of the vehicle, disassemble it, and clean it, then reassemble, and put back into the vehicle. He said resetting the ECU would basically be an incorrect fix, since it's getting false readings from the MAFS.

gonna give that a go later tonight, will post with updates as they occur. Not sure which assessment is correct, they both sound plausible. Especially if the ECU was reset to the volume of air coming through the absolutely clogged filter. But cleaning the MAFS is probably a good idea anyhow, as is getting a new paper filter.

 

[MUSKYMAN]

quick update: contacted local british mechanic (LR certified), he says the oil from the filter probably contaminated the MAFS, to fix, simply take it out of the vehicle, disassemble it, and clean it, then reassemble, and put back into the vehicle. He said resetting the ECU would basically be an incorrect fix, since it's getting false readings from the MAFS.

gonna give that a go later tonight, will post with updates as they occur. Not sure which assessment is correct, they both sound plausible. Especially if the ECU was reset to the volume of air coming through the absolutely clogged filter. But cleaning the MAFS is probably a good idea anyhow, as is getting a new paper filter.

the adaptive values will be off none the less and should be reset to make it run correctly.

 

[gmookher]

where can I finf info on what a 'drive cycle' is for a d2?(just curious)

 

[MUSKYMAN]

A drive cycle is when you start it , it warms up and goes into closed loop operation and then is shut back down.

 

[ptschram]

quick update: contacted local british mechanic (LR certified), he says the oil from the filter probably contaminated the MAFS, to fix, simply take it out of the vehicle, disassemble it, and clean it, then reassemble, and put back into the vehicle. He said resetting the ECU would basically be an incorrect fix, since it's getting false readings from the MAFS.

gonna give that a go later tonight, will post with updates as they occur. Not sure which assessment is correct, they both sound plausible. Especially if the ECU was reset to the volume of air coming through the absolutely clogged filter. But cleaning the MAFS is probably a good idea anyhow, as is getting a new paper filter.

Wow! This guy is really good if he can make a statement like this with no caveats.


(if the CEL is not illuminated, it's probably not gonna make a difference)

 

[jhmover]

Well, I've had a K & N in mine from 119k to 243k, so far no problems. But - I don't over oil it either, which is what I think causes the MAF problems.

 

[knewsom]

how is it that the adaptive values can set themselves improperly due to incorrect MAFS data, but need to be reset via an outboard computer once the proper MAFS function is restored?

And no, no CEL.

 

[scottjal]

how is it that the adaptive values can set themselves improperly due to incorrect MAFS data, but need to be reset via an outboard computer once the proper MAFS function is restored?

And no, no CEL.

Well if you want to take a long time for it to relearn you can do that...

Cleaning the MAFS isn't a bad idea though. I think you want to hose it with electrical contact cleaner, search this K&N issue has been brought up many times here. Myself I needed a MAFS about 100 miles after the K&N was put in. Now I run paper in this sensitive truck.

 

[leftlanetruckin]

i had the same issue on our p38.
cleaned the maf with maf cleaner from the parts store. helped a little but still idled @900 rpm's.
went through all the normal steps to no avail.
took delivery of my faultmate msv, reset the adaptive values, and presto. idles exactly right, and hasent gone back to a high idle since.
i would recomend the faultmate system to anyone that wrenches on thier own rover, paid for itself in no time with me. hell, probably worth it for the eas alone in my case....
you could try disconnecting the battery for a while, just be sure to have all radio codes etc beforehand!!

martin

 

[ptschram]

how is it that the adaptive values can set themselves improperly due to incorrect MAFS data, but need to be reset via an outboard computer once the proper MAFS function is restored?

And no, no CEL.

Sigh.

It's been a long day in a long hard week, but the '59 SII is finally done and has brake lights and turn signals now. After such a week, I'll cut a newbie some slack.

The engine control unit in a DII and a GEMS DI has the ability to make minor changes to engine control outputs to compensate for engine wear, fuel variation and driver habits. As the vehicle ages, the inputs to the computer change and the computer makes changes to its outputs taking changing input conditions into consideration.

As your K&N filter became obstructed, the ECU recognized a reduction in airflow through the MAF, while things like throttle position did not change to the same extent. When you removed the obstruction, the engine is now receiving more air with the same throttle position, as a result, things like air/fuel ratio are not optimized.

At this point, there are two main directions to go to correct this condition. 1: obviously is to reset the adaptive values to baseline stored values. 2: is to merely tolerate the poorer performance until the ECU has logged sufficient start/stop cycles, engine temp cycles, engine speed cycles, etc.

Clearly, the most effective means to return to optimum is to have the adaptive values manually reset via the OBD-II diagnostic port.

Is that a good enough explanation?

BTW-buy a service manual or a Rave disc, the theory of operation of themain systems of the vehicle are provided there. IT is near impossible to diagnose one of these vehicles without knowing how it works and what does what.

PT