My 97 runs terrible when hot
 

Hi all. New guy here. I've got a 97 series 1 that runs like crap after it gets heated up. It runs great when the weather is cool/cold but as the temps outside go up the harder it is to start and the worse it runs as it gets the engine gets hotter. It starts with a severe power drop (feels like about half) and then if it gets hot enough it will start chugging and sputtering. I've changed plugs and wires, cleaned the throttle body and replaced the mass airflow sensor. When it gets warm it actually runs worse with the new masf. I returnes it and they sent me another one and the results are the same. I'm out of ideas and hoping someone here might have an idea. Any help is appreciated!

Jason

Thermostat maybe? Fan clutch? Coolant level. Someone with more knowledge will chime in.

How old are the O2 sensors? When confronted with this type of problem it is very useful to look at live data (specifically fuel trim, throttle position, and temps).

An OBD dongle + an app (<$30), and a smart phone will go a long way.


https://landroverforums.com/forum/di...02/#post581013

Never had an idiot light come on so assumed it wasn't throwing any codes. Not sure the age of the O2 sensors. Knowing this old beast they're most likely the originals.

Live data is likely to shorten the path to recovery on this one. We'd be doing a whole lotta guessing otherwise.

....and if I was guessing I'd say..... https://www.roverparts.com/Parts/ETC8496

When starting first thing in the morning if it's already hot and humid out its a bear to start but then runs fine until the engine gets hot. Would this part still br a likely culprit when staring cold?

Yes it would although it would start ok and then run bad once the coolant is warm. It makes the motor run overly rich when it fails. Have an auto parts store scan your Disco to see what codes come up.

Fuel Temperature Sensor - that's my guess as it sounds identical to the issues my friend had, and he replaced the usual suspects... once he figured that out, no more issues starting when warm.

There is a seller on eBay for $40 vs $187

Codes will be definitive though ;)

It COULD be lots of things (including the VSS). The live OBD will reveal if any of the sensors have gone wacky.

You COULD throw money and parts at it, or spend $30 and have a much shorter path to diagnosis.