temp reading raise but ECT sensor drop ???

[bl4ckclio]

as topic

2004 Peugeot 406 EW10J4 Auto

when scanning with PP2000 -> Engine ECU Test -> Injection -> Parameter -> coolant temperature

something strange I see.
when first start the engine, gauge reading about 40->50->60 C, I see coolant temp show above 60 C.
engine warmer, about 80 C, PP2000 parameter show the engine coolant temp below 60, about 55 C
when gauge hit about 90 C, parameter coolant temp show 48 C.

I see on screen PP2000, constrain for coolant temp should between 80-110 C.

Bought new genuine coolant temp, replace the old ones, show the same !!!!

trace the wiring from ECT connector to engine ECU....nothing wrong.

I feels heavy acceleration at low RPM which I think maybe to rich.
my MPG about 17,3L/100km.

what should I have to do, Mates????

thanks in advice, Cheers.

[jasper5]

Have you replaced the engine management coolant sensor or the engine coolant sensor?

The engine management coolant sensor is what you should replace.

[bl4ckclio]

Have you replaced the engine management coolant sensor or the engine coolant sensor?

The engine management coolant sensor is what you should replace.

yes, which I have replaced is engine management sensor.
it's a green one.
p/n 1338A7 base on servicebox.

[steve_earwig]

17,3L/100km

That's about 16mpg, appalling

SEDRE says green connector too

No other faults logged?

[bl4ckclio]

17,3L/100km

That's about 16mpg, appalling

SEDRE says green connector too

No other faults logged?

PP say no fault found

[Doggy]

Could you possibly have an airlock in the region of the sensor - (it'll read cold if it's not immersed in coolant)?

[bl4ckclio]

Could you possibly have an airlock in the region of the sensor - (it'll read cold if it's not immersed in coolant)?

thermostat stuck closed?

but the Tstat housing hot enough to transfer heat to ECT sensor....?
but I'll try to bleeding the coolant.

wanna ask mate,
so temp gauge, engine management, and fan are controlled by this sensor only?
no other?

[steve_earwig]

but the Tstat housing hot enough to transfer heat to ECT sensor....?

Unless it's insulated from the housing...

You should be able to tell if the thermostat has opened as the radiator & pipework will suddenly get a lot hotter.

so temp gauge, engine management, and fan are controlled by this sensor only?
no other?

The fan is also controlled by the pressostat (I don't know either but the diagram shows it somewhere about the ecu end of the radiator)

I'm quite hopeful of the airlock suggestion, mainly because we otherwise got nothing

[Doggy]

The fan is also controlled by the pressostat (I don't know either but the diagram shows it somewhere about the ecu end of the radiator)

I think that's how rad fan overide for when aircon's running works on earlier, semi-mux cars. On this 2004 vehicle, aircon control is handled by the engine ecu, which operates the compressor clutch and rad fan as necessary. The pressostat is replaced by an analogue pressure transducer, (which looks the same), - at least that's what happens on HDi's.

[steve_earwig]

Hey, it's what's on the wiring diagram, maybe they didn't bother changing the name. I dunno what's inside it but it has 3 wires, all heading into the ecu.

[bl4ckclio]

allright,
after my car sat down for 2days, I try to diag before started it (cold engine)
outside temp show 21C, the coolant temp 70C and air temp 55C ........???

so I think both coolant and air temp are false.
not only coolant temp.

any suggest?

[steve_earwig]

Is that inlet air temperature?

[Doggy]

Probably - unplug the MAF and see if you lose the reading.

[bl4ckclio]

Is that inlet air temperature?

yes.

[bl4ckclio]

Probably - unplug the MAF and see if you lose the reading.

MAF=Mass Air Flow...??
there isn't on EW10.