weird idle and alternator

[Hoot]

High idle

I have a 2 part question for you all.

2 days ago my 96 D1 started acting a little strange. When i start it up the rpms jump to around 1500 and it just ides there. I give it some gas and the rpms raise and then drop right back to 1500. if i switch it into gear the rpms drop down to normal. around 600-700 rpms. this has happened beofre and usually turning off the truck and restarting solves the problem. however that is not the case anymore. it does it everytime i start the engine.

i checked the IAC and claned it it seems to be working fine, i had guessed it was not the IAC anyway because i cleaned it a few months ago. I also removed and checked the TPS it was not dirty and was functioning ok.

while i was poking around under the hood i started the engine and let it idle and gave it a little throttle a few times to listen to the engine. i found that after i would throttle up and release the engine would bog down to like 200 rpms and falter a bit. I also noticed a new engine whine noise. i go tmy stethescope out and found out it was the alternator, which by the way is he 4th rebuilt alt since late january. i had noticed a bit of increased whine noise over the last few weeks but had assumed it was just, worn difs, trasfer case etc.. but no its the alterntor. after isolating the whinning i turned off the engine to check the alt. connections. as i got my head over the alt i could smell a distintive burning smell coming from the alt.

So granted i need a neew alt. but would a failing alt give me idle problems like i described? if not what else should i check?

Now for the 2nd part. i am through with rebuilts. I can now swap an alterntor out in 15 minutes thanks to all my "practive" but i am tired of doing it. What would yo uguys recommend for a new alt? mean green? New magna marelli? let me knwo yer opinions and where i can get one at the best price.

thanks for your time.

 

[Robbie]

maybe stepper is just bad and beyond the cleaning point? could also try resetting base idle.

i replaced my alternator with a mean green a little over a year ago and have loved it. at the time, i couldn't take the truck off the road, and noone local or even online part houses, had a replacement/rebuild for under $280. for that price, might as well look at brand new upgrade of mean green, and looked online and found a place that was selling them for $299 - mad4wd.com. Mine does whine a little loudly, not sure if that is par for the course or not, and i did have to ground the case to the battery to keep the whine out of the radio, but it seems to work great and puts out a lot of juice.

 

[Jim]

I went through a few alternators before I took it to a very reputable auto electric place and they found a fault amidst the harness that was cooking the alternators - with Lucas sometimes you need to seek a higher source.

Before getting too deeply involved in your idle problem, put a few drops of light oil on the throttle linkage and springs on the butterfly there under the hood. I went the same route, stepper, TPS, plenum, but it wasn't fixed until I lubed that linkage - now I put a few drops of sewing machine oil on the linkage every time I change the oil.

Best of luck!

 

[Hoot]

updated: but still have questions

i have now installed a brand new OEM alternator and had discovered that somewhere along the line the bad alts wore down my optima to the point where it would no longer hold a full charge. I went to the battery shop and the service guy did a load test and it failed, luckily the optima was within warranty and i got a new one no questions asked.

But alas the high rpms at startup is still there. i have come to recognize that once the truck gets good and warm it will go bakc to idling within the normal range, 650-750rpms. Until that point it will idle a bit high when it is in gear (850-950) and if i shift it nto park the rpms will jump back up. Now once it is fully warmed up it ill idle near normal both in gear and in park.

i have checked the throttle body, and givin it a little lubrication, i have cleaned the butterfly valve inside the plenum, i have cleaned the MAF, and used some electrical cleaner on the connectiosn to the MAF, and to the aiir box sensor and the plug on the IAC.

can someone tell me what is most likely the culprit? or what else i should check?

 

[RoverChic]

Well same here ...D1 1998 78K miles ..Just replaced the Fuel pump and now the Rover is Reving @ well over 2000 RPM. Alt is fine 13.89V/ so is the starter 12V/battery. Only happens in Drive and N that the truck will rev well over 1500-1900 RPM. Will drop back down to the usual 800 RPM only in Drive/Reverse/3rd ect... I have checked the throttle body, I have cleaned the butterfly valve inside the plenum, checked the stepper motor... The only thing that seems to solve the problem is disconnecting the battery.. I took it to the shop today and they said idle circuit? Any help is appreciated.. There are no codes ..One PD code P1185 (02 sensors).
Sometimes when I turn the A/C on it helps to drop the rpms ..But not much. TIA!!
Melissa

 

[TNdisco]

I have had the exact same idle problem as hoot...for the last 4 months! I don't really mind it but i hope it doesn't have long term effects. hoot - If you find out what the problem is tell me so i can fix mine

 

[Hoot]

heres another weird addition. Tuesday night when i got home from work my top hose on the radiator sprang a leak. It happened at the exact moment i pulled into my driveway. spewining neon green scalding hot liquid all over the enigine bay. smoke everywhere. it wasn't pretty sight.

well to make a long story short i got my new hoses from Nathan today and i swapped out the top hose and started her up to check for leaks. the kicker is the idle is now over 2100 rpms. so what does tell us? i have no idea.

i am also replacing my bottom radiator hose so as to prevent the same thing form happening again. SInce i am going to have to drain the coolant i am also replacing the thermostat, and i will clean the electrical connections to the water temp sensor. not sure if it will have any effect on the idle issue but for the extra $9.00 for the thermostat i figure its worth trying.

unrelated to the topic at hand but speaing of cleaning the electrical connectors. i pulled out my MAF last weekend and cleand off the sensor wires, along with its electrical connection plugs. The result was pretty damn good. the throttle is noticably more responsive. It actuall feels like it has a lot more "get up and go" so that was a nice little treat. now if i an just get the idle down....

 

[RoverChic]

Well third mechanic today ..Idle is still high well over 2000 RPM in Park and Nuetral.. 1100 in all other gears ...Repalced the IAC again (3 rd new one today) .. I am at a loss. This never has occured before the new fuel pump ...

 

[Hoot]

mellisa a fellow dweb member Corey (Discobro), had a similar high idle problem and he to replaced the stepper to no avail. Finally he found a rover mech that explained that sometimes the wiring that goes to the stepper is faulty and thus causes a functioning stepper to seem like it is malfuntioning, but in reality the stepper is fine and the problem is in the wiring. Corey never had it fixed, and has since had his fill with rovers and sold his.

i dont know if this is the issue or not but it seems to be a problem that happens to a lot of us disco owners. hopefully one if us will solve our problem and end the dilema for us all. however my fear is that each one of us have differnent problems resulting in the same symptoms (high idle)

keep me posted melissa...

 

[RoverChic]

Hoot: First and foremost thanks for your post. I took it just now to a shop that specializes in Metric Autos, the tech told me that, as I believe somebody else pointed out, that the ECU has to be re-mapped after the second fuel pump was installed. I was told by someone on another Land Rover board that my problem had absolutely nothing to do with the fuel pump (and to get it out of my head that the high idle problem was not related what so ever to the pump) henceforth I never mentioned the new fuel pump to anybody but Rover Cannibal (the people who fixed it to begin with ~ the fuel pump). After the fourth plus mechanic (I decided to tell him about the fuel pump) he said that the ECU was *confused* for lack of better words. There is more to the story and I took notes over what the Tech told me. If you need more info or if there is anything that I can do to further assist you with your problems send me an email and I can forward you what I have over our apparent high idle issue's.

Best, Melissa N