Hello everyone,

I have a 97 Disco. When I first got it there was an intermittent stalling problem. It usually only happened after a short drive where I shut it off and tried to restart. It would run perfectly from cold until I restarted. To get it to run I would need to press the accelerator pedal while cranking and keep holding it a little to keep it from stalling while driving (at stops). It has gotten progressively worse and now it does it all the time. I've replaced the IACV, fuel filter, and checked the TPS with a multimeter. I also cleaned the MAF and throttle body, following the directions from previous posts. I am able to tighten the throttle cable enough to keep it from stalling but would like to not have to do that. There worst part is there is no check engine light!! Any help is greatly appreciated!

I've heard of faulty engine coolant temp sensors can cause this, but the engine temp gauge is acting normal. Does the disco use two engine coolant temp sensors? Also, the vehicle speed sensor I've read can cause this, but again the speedometer is working.


-Adam

 

Are the spark plugs fowled out with black soot?

 

Just checked the spark plugs, all were normal except one had very small amount of soot

 

Possibly fuel pressure regulator, check the vacume tube for cracks, splits or a bad connection. It is not uncommon for the regulator to fail. Hope it's not a sign of the fuel pump.

 

Mine would stall out at idle every once in a while and it turned out it was a weak battery. Popped a new one in it and haven't had a problem since.

 

I checked the fuel pressure regulator. With the throttle cable tightened down to keep it from stalling it reads ~30psi, when I disconnect the pressure regulator it goes to ~40psi. Are those about normal?

CUpgt, did you have your battery tested? Did it show up as bad? I'm wondering if I could take it to the parts store and have them test it before I spend the cash.

 

With respect to the question about two temp sensors, yes. That is a common design. They are very near each other on the front of the left side of the engine, near the thermostat housing, the guage sensor has one wire and is round, the coolant to ecm sensor has a two wire rectangular connector. In the RAVE download of electrical troubleshooting guide, they can be found on section A1 - page 6 (X126 Engine Coolant Temp Sensor) and the guage temp sensor (X114) is on Section E1 - page 5. The photo of the location is section Z5 page 4.

Not sure how the Rover responds, but many Ford engines idle higher and higher with a defective coolant temp sensor, the ECM thinks the engine is cold and increases the fuel mixture, dump on more gas.

 

Took the battery to auto parts store, they tested it and said it was fine.

If the coolant temp sensor was the problem and I disconnected it, would it potentially idle normally?

 

A faulty coolant temp sensor will not do anything to the idle, all it will do is increase fuel to richen up the mixture.
If you unplug it you will get a check engine light and probably really bad MPG.
This is typical bad/clogged IACV.
Did you use a brand new IACV? Did you shut the engine off and wait 30 sec before unplugging the old one and then plug the new one in before turning the key back on?
Per the Rave manual, if the engine will not idle below 550 rpm but will run with the throttle being held over 600rpm then the IACV is faulty.

 

Spike,

I replaced with a new IACV. It took me a few mins to switch out the valve. The symptoms seemed to be the same with either IACV. Has anyone ever gotten a bad new one??