disco engine issue...help

[pete2528ca]

Hey all.

I am a long time lurker, and have asked very limited questions, but now I think I may have a doozie.

My truck starts fine, runs well, but when the engine is hot, it struggles to start and has a really crappy idle, to the point that it stalls out. It doesn't happen often, but it does when the engine is hot.

My disco is a 97, 160,000km, 4.0 GEMS engine. There does not seem to be an issue with the head gasket, oil is clean, coolant is clean.

I have installed a new engine Coolant Temperature Sening Sensor, an Engine Coolant Temperature Sensor (ECTS), a new thermostat, new wires, new plugs, new air filter, change the oil regularly, did the seafoam treatment through the plenum. Cleaned the MAF, Stepper motor, and the Idle positon sensor.

I am at a loss...

I am throwing lower O2 sensor codes and have the lower sensors in the mail.

What else can it be?

 

[greg409]

Sounds like my '96 4.0 RR
I replaced the crankshaft position sensor (behind exh manifold driver's side facing rear of car, thru the bell housing, sensing pulses on flex plate (was that a run-on sentence?)
$70 @ dealer for part 1-hr change
This seemed to eliminate the poor-starting-when-hot&-dying issue.(although it wouldn't start a year later when I sold it!!!)

My '97 se7 has the same engine, but it's been great.


Replace the o2's 1st tho'

I'm sure someone here will also chime in'

luck,greg

 

[joey]

how much fuel is in the tank?

the reason I ask, is I am thinking 1 of 2 things... fuel pump is hot and not working properly, or maybe bad/dirty injectors

What type of spark plugs did you install?

Which code are you getting front or rear O2 sensors? if rear, could be bad CATS.

 

[pete2528ca]

i am getting P0138. the Cats are two years old, and just generic ones that speedy muffler put in. the tank is always at the very least half full. Spark plugs are the tried and true Champion recomended ones and i put NGK wires in.

It is rear O2 sensors. I have them on order.

Can the Cats do this?

I run injector cleaner frequently, and seafoam too.

 

[joey]

High voltage on the O2 sensor could very well be a bad O2 sensor, since you already have them on order you should know soon.

 

[pete2528ca]

changed the o2 sensors, and have the same problem?

could it be the fuel temperature sensor? atlantic british lists this as a culprit.

any other ideas?

 

[pete2528ca]

vaccuum lines?

 

[wolf]

Hi Pete;

I am thinking fuel temp sensor as well - it jives completely with what the manual says its purpose is: i.e. to facilitate good warm/hot starts. It may be an aging fuel pump too - as Joey suggests - too bad they can't give us a warning about when fuel pumps are starting to soften - as that is when they seem to cause the most problems - ( i.e. you sure know when they quit but not when they are just slowly dying).

Wolf