Hi all,
With much help from this forum I've been able to rescue a 97 Disco from certain death. In just a couple of weeks you guys have helped me change the fuel pump, open the rear hatch with a sticky mechanism and generally become better aquainted with the truck. Now that shes a runner a whole new set of problems have become obvious. Idle is steady at 2k all the way thru warm up. Drops to 1k when in rev or drive and the second you touch the gas it stalls and quits. The truck will crawl all day in drive with the high idle but immediately stalls when you press the gas. Restarts every time and even high the idle is smooth and steady. Hoping this is all tied to the TPS or IACV. Since this is my first LR i was hoping for a little direction going into this from the voice of experience. I do have the RAVE downloaded and am using it as much as I can. I do have some fault codes stored and I'll scan them tomorrow and report back. Thanks for all the help so far, its greatly appreciated.

Keith

 

Remove IACV. Spray it with carb cleaner, do not "adjust" or "move" the pintle. It is a 200 position stepper motor, and darn delicate. When you power up truck you should see it move. Also clean the bore it pokes into, and the butterfly valve of the intake (TPS monitors that position). The IACV is a computer controlled vacuum leak.

At this point avoid temptation to clean MAF, it must be done with MAF spray when truck is stone cold.

If you have a scanner read the coolant temp when truck is cold. A bad coolant sensor or one that is unplugged will read -40F as ambient temp and ECU will make high idle as well.

 

Hello to our new member from Newnan. I was born and raised in Griffin, my dad's sister and her husband owned the Quaker State Oil distributorship in Newnan many years ago.

I agree with Sava on a thorough cleaning of all the intake plenum ports and the IACV and TPS along with closely ckecking/replacing the two small hoses that recirculate the exhaust fumes back into the intake.

Also clean that MAF real good when it is cold. You may also need new O2 sensors. Or t least look at plugs and wires. Also clean all the linkages involved with the throttle and take a look at the cruise control mechanism and the actaul mechanical linkakes for the throttle as they can bind up and cause similar issues.

 

Hi all,
Just a update on this issue. I did pull the IACV and it was filthy. Cleaned the valve itself and the bore with carb cleaner. Then used MAF cleaner on the MAF sensor with it bone cold. Once back together it ran much better......for a bit. After a short while it was back up to 2k idle although this time it seemed like it was trying to correct itself. sigh....frustrating. The stalling issue never got better and it still continued to stall the minute the accelerator was touched. Unplugging the TPS had no effect either positive or negative. Curious if you guys believe a new IACV is in order or should I be testing another component?

Oh yeah the codes I pulled were P1496, P0420 and P0430. I believe I took care of 1496 when I replaced a missing gas cap. Hopefully the 0420 and 0430 are gone as well by replacing the plug wires. One wire was not even connected good and another was falling apart at the connector.

I believe if I can ever solve the high idle / stalling issues there may be hope for it. Just not sure if my patience or sanity can last that long. I'm just coming off a 80% restoration of a BMW 633csi that had me pulling my hair out. Oh how I love the Disco though.......

 

The ECU has to re-learn the settings of the clean IACV, so some driving may help. Certainly won't hurt to try new IACV. ECU will use a default value if TPS fails.

 

I'll try to get this out on the road although the stall issue is so bad it might not let me. Unless I cruise around at 2 mph and 1K rpm. Hehe. I'll continue to let it run a bit each night after work and see what happens. Hopefully it will work itself out. It has been over a year since it even ran and its not like I dont have anything else to work on.....Non-op sunroofs, back windows that dont roll up or down and a saggy headliner just to name a few....

 

Leave sunroofs alone if they a'int leaking. Rear windows can be ground wire at rear disable switch in center console, or cold solder joint in window ECU at glovebox. I have wondered on the saggy liner if you could poke hole in fabric, use spray adhesive thru a little straw (like brake cleaner size) and spray inside, then use a paint roller to push it up in contact when tacky. That would leave a couple of very small holes in the material.

 

Just yank that headliner out, the foan layer decays and they fall apart. Some people recover and put the fiberglass shell back in, some have painted it and a few like me have just done away with it totally.

What octane are you using in it? The higher the better!

New plugs? The cheap Champion coppers are what comes in it and they do fine.

Did you clean the throttle linkage good?

A vaqcumn leak in those little hoses will give youy problems, so you should replace them and then try running it hard even if it is in a vacant lot or something.

Take it off-road and put in in low range, that will allow you to build up some rpm's if it will do it. Injectors could be nasty as well.

 

hey Savannah - Front sunroof not leaking but the rear is completely missing the glass. It's definitely a inside Rover for now. I saw a post on the soldering of the window card, I may try that. Being in the aviation industry I'm pretty handy with a soldering iron. I'll start there and also look at the lockout switch. Neither one of the rear switches on the door operate the windows either, so hoping its not two regulators. Id rather do the soldering!
The headliner trick you describe is exactly what I was planning to try. I'll let you know how it turns out. My only fear is the 3M super adhesive is thicker than snot so I'm curious how much will actually push thru the straw.
Again, my biggest fear is not being able to diagnose this stalling issue. I mean it truly will not budge if you press the gas. The stall is immediate. The only time you can avoid the stall is in park when you can very rapidly press and release the accelerator to rev the motor and keep it running. Try that in gear and you're going thru the garage.....

Anyways, thanks for the help its much appreciated...

Disco - Just rolled thru Griffin last week going to visit my dad in Jenkinsburg. I dont think Griffins changed a whole lot, it looks the same to me as it always has...

 

Have you tried pushing the throttle while lightly holding the brakes? Just wondering......

Give this a try, it's worked for a couple of buddies and me. Normally high idle can be only technically fixed by reseting the ECM variables. That requires a hook-up at the dealer or an indy LR mechanic. Reset allows the ECM to learn the exact position of the IACV plunger and then can step up from there. That's going to be it's baseline zero.

This is the "other" method; Unplug IACV, turn ign switch to posII, wait five seconds, turn off ign. Plug back in, turn ign switch posII, wait five seconds, turn ign off. Repeat this three to five times. Might reset, might not. YMMV.