Idle issue!!!

[Craig]

Howdy guys (& gals) New boy in town re the Land Rover Discovery, well I say newby, I had one of the first back in 1990 TDi 3 door. Anyway, I just bought a series 1 1993 V8i and some times it just cuts out while driving at low speed ie when the idle kicks in. Car has done 115,000kms from new and is ex Japan. Any ideas how to sort it or is this a dealer issue to sort out. Im not impaired but this type of car is new to me as in im only used to 4 & 6 cyl vehicles!!!

Anyway, great to see a specialised site for this truck, its had aftermarket springs fitted as well as shocks. Off in the morning to have an aftermarket anti-swaybar fitted as it seems to roll big time on bends (this also may be the way I drive )

Catch up soon, Craig.

[me.guevara]

From what I understand, there are many causes for the problem you describe, from electrics/electronics to fuel management to engine issues.

I've been battling a similar problem due to a bad idle bypass valve (aka stepper motor), but I've already done the easy stuff: check connections to/from coil and distributor, check/change spark plugs, push a carbon deposit cleaner through the engine (see the seafoam thread), etc. I'll let some of the more experienced DIYers say more...

Welcome to LRO!

[Craig]

Cheers for that mate, I just got back tonight from a 12 hour drive and it now seems OK but what I did prior to the off was to adjust the twist adjuster on the cable, I know its not the best way but it works perfect now. Infact it seems to idle more solid too at 800rpm with no ups & downs. I had both the cats taken off the other day too as they are kinda restrictive on the exhaust flow.

The new Swaybar was also fitted today and WOW what a huge impact that is, its an aftermarket unit from Whitline in Australia. We have a dealer here who imports them so thats a bonus. Going to look at one for the rear but not too sure if it actually needs one now as it goes round corners great. The roads where we live are really old farm tracks with tar seal on them so there are some unreal corners to throw it about on and to be honest the swaybar is a totally unreal upgrade from what it was

Thanks again mate and this may I say is a real cool site

[tonka_thom]

Hi I am in Wellington and have jsut my removed my cats as well, you need to get the tuning resistor replaced in the Engine Management system, that could be the problem.

also remove the idle bleed (stepper motor) and fill it with CRC and drain it several times, also hold it upside betwen rinses and give it a tap to remove any carbon as it can get crap in it from the PCV valve.

are you running on Premium?

[Craig]

Hi Tonka, its now running perfect so not too sure what to do now!!! Its looking like I may just drop it in to Land Rover on the North Shore (Auckland) on one of my next trips for them to check the whole thing. Only issue I have with dealers is they always set the idle to the book and its alway too low for me. Taking the cats off was a huge diff to the take off too & I get better mpg but not that that matters... How was yours after you took the cats off.

I run 95/98 in mine, and yes I have done it, I put 91 in there and it sounded like the big ends were about to crash!!! Dumped the whole tank of gas and filled up again (Wont do that again)

[Craig]

OK, so who has a picture of this "Stepper Motor". I am going to have to do this prior to the dealer visit as I dont want my pants taking down when I get there like dealers do!!! I just replaced the leads and plugs & it still has an up and down idle, its almost a constant up and down too. The temp'ry fix is still OK but really need to sort this proper Any help would be great.

Its also going for the big exhaust job in the morning, taking out the big centre box out and its getting 2x cherry bombs fitted LMAO and I thought id grown up at age 42

[tonka_thom]

Hope this helps.

The big chamber that sits in between the 2 backs of pistons is called a plenum chamber. Instead of opening and closing the throttle butterfly, they bleed air into the chamber and the engine management system raises the idle.

At the very back of the right hand side of the chamber (left as you stand at the front, looking back) there is a protrusion that has some wires on it. Inside is a stepper motor that winds a piston in and out to let in air.

You can do some things such as disconnect it to see what happens and if the engine is racing try tap it to loosen any crap that it may have picked up.

With the engine off do the process mentioned above. As long as you are careful disconnecting the leads, and putting it in and out you should come to know trouble. On mine when I tip it up (or blow compressed air in) nothing comes to pieces.

You will need a large spanner, so be careful not to over tighten

[me.guevara]

Here's a picture of both the location of the idle air bypass valve and a the actuator itself (the stepper motor).

You can replace it by the OEM part (~US$190) or by a Chevy part (AC Delco ~US$50) - see http://www.rangerovers.net/discoparts/#efi - scroll down a bit to "idle air bypass valve".

The OEM part number I got is ERR5199, while the AC Delco part number is 217-437.

The stealer here (Bolivia) wanted US$400 for the OEM part, so I'm having the AC Delco part shipped and should arrive this week - I'll let you know if it resolves my problem - there's a slight possibility that in both our cases, it's not the definitive fix, but here's trying!

BTW, from what I understand, it really doesn't need to be torqued on, slightly more than finger-tight is sufficient.

Good luck.

[Craig]

Cheers guys that's great, ill do the job in the morning. Had the new exhaust done today and it was a good job too, some clown had replaced the last rear muffler with the wrong type and thats why it was struggling to perform, rear exhaust should be a straight through type and mine was restricted!!! Sounds like a drag car now lol but goes heaps better (good old "Pit-Stop") Thanks again guys and ill let ya know how I get on, cheers, Craig.

[FelixLockhart]

what I did prior to the off was to adjust the twist adjuster on the cable, I know its not the best way but it works perfect now. Infact it seems to idle more solid too at 800rpm with no ups & downs.

I just did this on my truck, and it sounds a LOT healthier, thanks for the tip! It had been idling at 500 or less, and sounded like a diesel trying to kill out. Now it sounds and feels a lot stronger at idle, and there's less play in the throttle pedal

[Craig]

Well, here goes, it was not the stepper motor, it was not the ht leads, not the plugs, not the injection unit, not the dizzy but it was the vacume advance & retard unit I took it to a performance shop in Auckland and they had it all down to a tee in like 20mins... Land Rover wanted $235.00 for the unit (recon) and the shop had them (same unit, same brand) for $85.00. The unit was just solid and not doing a thing but hey, iv a wife just the same so im used to it

[me.guevara]

Finally got my stepper motor! The Beast now purrs like my Waring (the LR of blenders - kinda makes me thirsty, come to think of it).

I went with the AC Delco generic part for the Chevy Astro V-6 (US$52 excl. shipping) - that's at least US$120 less than the stealership part in the US; here, it's about US$300 less than my stealership was asking. The savings paid for shipping, and them some...

I haven't taken it out to test the depth of the fix, but on start up and warm up (about 5 mins), it idles like a new engine.

The mechanic had unplugged the harness to the bad actuator, basically eliminating that input from the ECU and zeroing the fluctuations out, but my fuel consumption was way too high (idle was at about 1,100 rpm).

I'm taking it for a spin in a few minutes - I'll let y'all know if it doesn't work.

Now, the "only" thing I need to correct is this funny crunchy sound coming from the alternator (I've known I need a replacement - I was hoping it would hold up 'til year-end).

It never ends, but I like the Beast too much to complain...

Here's a shot of the new stepper motor:

[FelixLockhart]

I just replaced mine, too. Not sure if it actually made a difference, since mine was only having this issue in the rain. I guess I'll find out next time it gets wet

[Trey]

Hey guys, I just replaced this part on my 95 Land Rover as well I was getting the same code. Anyway how do you get the check Engine light to go off I took the battery leads off the battery for about 30 minutes and then placed them back on and went for a ride the truck ran flawless but the check engine light came back on.

[me.guevara]

Originally Posted by Trey

Hey guys, I just replaced this part on my 95 Land Rover as well I was getting the same code. Anyway how do you get the check Engine light to go off I took the battery leads off the battery for about 30 minutes and then placed them back on and went for a ride the truck ran flawless but the check engine light came back on.

We've got different model '95s, because I only see my CEL during startup and have never had to reset it.

From reading other posts on this board, I think I recall something about a reset button on the ECU, but we'll need to wait for one of the other enthusiasts to chime in...

Way to go on the "Search" function - I like the fact that you found this thread and that it was helpful.

Cheers,