Hi,

My recently acquired 1997 Discovery 1 V8 has 170k kilometers & stalls everytime the automatic transmission is shifted from neutral to drive (or any other gear including, reverse) after the engine has been warmed up for about 10 minutes. Has not done this (so far) when engine is still cold. No engine warning light on the dashboard.

Otherwise & provided it is kept in gear, idling is maintained at about 750 rpm (even during extended stops at intersections or in traffic) & the engine seems 'normal enough'. Manage using the 'one foot on brake & other foot on gas method' but not a good situation (even for a weekend drive out).

It has immediately restarted (again, so far) after the ignition is turned.

The previous owner (second, me being her third) replaced the stepper motor (OEM) & fuel pump (Mitsubishi Pajero part) only about two years ago. The former owner's repair shop says that I should try using her more as petrol engines tend to easily 'gunk up' (my previous experience with Land Rovers has been limited to diesels).

Would greatly appreciate any ideas on the matter.

Thanks,

 

Where on surface of the globe are you?

Check fuel pressure. On the fuel rail of the right side of the engine is a valve (like a tire valve), a gauge should show 32-34 PSI. Areas of concern include fuel pump, fuel filter (right rear wheel arch), and fuel pressure regulator (left rear of engine, has small 6 inch vac hose that easily cracks).

New plugs and silicone 8mm wires should be on every new owners list, the original grey ones will crack and break down.

Anytime idle load changes are involved I think of the IACV stepper, it is a computer controlled vacuum leak. It can be removed and cleaned with carb cleaner, don't move the tip, leave that to the computer. Also clean the bore it came from. Clean oem style air filter.

You may have a vac leak somewhere that is allowing un-metered air (which did not pass the MAF) into the system. So the computer is changing the IACV position step, but not getting the reaction you want.

The MAF sensor can be dirty. It can be cleaned, but that shoud be done only when truck has sat overnight (stone cold), the key has not been turned in the ignition (it heats up the MAF sensor inside 350F), and use only made-for-MAF-Sensor cleaning spray. The sensor used to sell for about $1400.

A can of SeaFoam or other gasoline solvent in the tank is worthwhile from time to time, but my D1 seems to run fine without it on the current assignment as college car for offspring. Maybe 35 miles twice a week (yes, they will bring laundry home if they think you will take them shopping).

The factory shop and owners manual set is called the RAVE, free download below. Also in our technical sticky area you'll find lots of things you can do yourself, including the high miles service list.

 

If you can move the tip of the IAC, it's broken. The shaft of the IAC is held in position by tabs on the end of the shaft while a threaded wheel inside the unit turns to move it in and out. If nothing holds the shaft from turning, then the threaded wheel will just spin the shaft and in won't move in or out as it's supposed to.

 

For my '99 DI it was the Engine Coolant Temperature sensor. Replaced it and the problem cleared.
SD

 

Yep, forgot that one. The ECT should show a logical value on your scanner, like ambient temp in the parking area. Not -40F (disconnected). On a D1, the heat gauge sensor and the ECT sensor are separate, but stand beside each other. Can make high idle. One with brown square top in pix.

 

.....and yes, you should keep her in good shape by driving her more often.

You only keep them happy when your chasing them around the kitchen table....same same.

 

Good afternoon.

Just took delivery of the vehicle after spending a week at the local (Philippine) Land Rover dealership for problem diagosis.

After some test drives by them, engine speed drops to 400-500 rpm (only upon shifting from neutral to gear/ drive when warm) but no longer stalls (even with airconditioning & headlights on). Although that still seems a bit on the low side, would suppose 600 rpm to be more like it?

They checked the fuel pressure (after I asked them too, as suggested by this forum) and it proved to be on the low side @29 psi (a new unit spec's @40+ psi per dealer) & given that 33-35 psi being the minimum recommended for normal operations (again, as cited by this forum). According to them though, no engine warning codes showed up in their diagnostic software.

They also inspected & found the spark plugs & related cables in order. The MAF sensor had already been previously checked by the repair shop of the former owner, who also changed the air & fuel filters, last November. Since then, the vehicle has hardly been used as she was being readied for sale.

So I intend to focus further investigation on the fuel system, beginning with the pump, pressure regulator & related vacume hose/s before looking further into the IACV stepper (which I figure might 'resolve itself' with more use if any gunk was causing it to move less freely), ECT or other sensors.

Given that the fuel pump was changed a couple of years ago to a non-spec unit (as mentioned, into a Mitsubishi Pajero part), that would make it my initial suspect (already canvassing for a proper replacement). But agree that the fuel pressure regulator is also a distinct possibility, will have that tested as well (there are fortunately, a few specialist repair shops in town who focus on older models).

Either of these I suppose might also explain why the vehicle requires priming the fuel pump (about 20 seconds) upon turning the ignition key on in order to start the engine more readily (something am conditioned to do with my older diesel).

At least, she did not stall on me again (from the dealership to the house earlier today) & even seems to be running a bit more smoothly now. I intend to take her for another extended drive out-of-town over the weekend to compare with our first trip to the hills a couple of weekends ago.

I'll know more about her after a more thorough mechanical inspection though.

Much appreciate the very helpful responses from no less then the Super Moderator of the forum & it's senior members.

Warm regards,

 

Finally replaced the fuel pump assembly (Delphi), cleaned the stepper motor & changed all fluilds & filters... pressure now @35psi, engine immediately starts on ignition, idles steadily (no longer stalls on load) & generally runs more smoothly (now know what a V8 is supposed to feel like).

P.S. Today was a proud moment for the City of Boston & the entire United States of America, we salute you.

 

Just returned from a 200km. road trip to a nearby province for Sunday lunch with family, the V8 was smoooth & didn't skip a beat. Fuel consumption @6-7 kms/ l (100-110 kms/ hr., mostly hi-way) wasn't so bad considering the vehicle's heft & relative quiet. My '97 Defender TDi300 although better @8-9 kms/ l is much noisier & vibration filled.

 

Greetings,

In the 4 months since my last post, I've had the IACV & throttle housing re-cleaned & base idle adjusted. Seems that the problem with the erratic idling causing the engine to sometimes stall on load wasn't just due to a defective fuel pump. Now, the engine promptly starts mornings & has (again, so far) not faltered at idle (even during a 2-hour traffic jam last week).

I also found out that my two electric auxilliary fan motors were not functioning (was not evident from the strong air flow coming from the main engine cooling fan & the fact that the temperature guage would be not go beyond mid-point) & had been duly replaced (with nippon denso parts). Also, replaced the wheel bearings (as a precautionary measure), brake pads & greesed all universal joints. Besides, odds & ends like a new headlight washer motor (the old one had given up the ghost but really quite unnecessary).

Am considering replacing the rear shock absorbers (in which case, the front one's would follow) to either Old Man Emu or TerrafirMa (the big price differential is hasn't gone unnoticed).

With these, believe she'd be about ready for a longer test run (out to the farm, 400-500 kms. of mostly hi-way driving) & perhaps some light off-roading (to test the proper operation of the transmission transfer case & differential lock, of course).

:-)