Technical Back again overheating seicento

[large1]

hello again peeps im back with another problem of overheating, after the last time the cars been fine, except that i always had to have the heaters on hot in heavy traffic which i can deal with..

anywayz the other day i did a short journey and the temp light come on so i pulled over and it did a polly(boiled over) i couldnt hear the fan, its a 2001 seicento schmacher no ac, i aint a newbie and changed the headgasket before on the car, renewed thermostat etc, but i cant find a fan switch anywhere, theres not 1 in the radiator for sure, does anyone know where the fan switch is on this car, i had problems starting car yesterday and think the ect sensor is also faulty as when i removed wire the car tried to start but run like a dog as the engine is cold, i think headgasket is ok this time but i think ill renew everything to be safe this time

any help is always appreciated if someone knows where the fan switch is on this model that will help, its NOT in the radiator like earlier models

thanx again mick

 

[fingers99]

There isn't a fan switch on the MPI cars. The engine temp sensor sends a signal to the ECU, which interprets it. If the ECU think's it's too hot, it energises a relay which allows current to flow to the fan.

First steps:

Check the fuse. It's one of the two behind the battery. Check them both as it's by no means uncommon for folk to put the cover on back to front.

Check the fan. Unplug the connector to the engine temp sensor (green coded sensor at the back of the inlet manifold, very near the thermostat). Start the engine and the fan should come on within a minute.

Download the manual -- Seicento Technical Manual in the "Downloads Library" in 3 parts -- note that it covers the SPI cars, too.

As it has overheated, do a compression test, just in case.

I'd not rule out the possibility that this is an SPI car to which some crazy fool has fitted an MPI radiator.

 

[Pep0]

The ECU uses sensor in the head or inlet and switches the fan via a relay.

If the red light in on and the fan not running

earth
fuse
relay
wiring and
fan

are suspects

try 12v to fan via two wires if it runs ok the other things are cheaper but you did check the fan spins freely?

 

[large1]

ok thanx for the prompt posting guys the fan does spin freely, ive just ordered a new ect(green switch by thermostat as i think this was faulty too, it could well be the relay by the sounds of it, do either of you know where its situated, maybe i could short relay, so does the ect sensor tell the relay when to trigger???, think thermostat is not working also as bottom hose was cold but top hot

thanx again guys if you could let me know about the relay

regards mick

 

[fingers99]

For God's sake man, test one thing at a time. You don't cure faults by throwing your wallet at it (or if you do, it's generally cheaper to use a mechanic/auto-electrician).

Did you unplug the engine temp sensor? What happened?

Did you check the fuse?

Have you downloaded the manual?

Don't short the relay -- you risk damaging the ECU which does the switching.

Locations, etc, in the manual. That, at least, will cost you nowt.

 

[large1]

thanx fingers ill download when indoors and have a read the parts on cost £22 lol so not worried, the car wont start atm as ect sensor is faulty also thermostat not opening ill try 12v direct to fan, once its running ill see if the relay kicks in and report back. its the missus car and she loves it, ive got a subaru impreza turbo which is more reliable pmsl thanx ill download manual tom and report back

thanx mick again

 

[rallycinq]

Did you check the fuses behind the battery?

Cheers

D

 

[Pep0]

you need a multi meter or a bulb with two wires attached to trace the 12v.

 

[blu73]

hang on, you say the top rad hose is hot but the bottom cold? Thats wrong, hot water flows from the thermostat down the top hose, through the rad and out the bottom.

Does that not mean if the top hose is hot and the bottom cold that water is not flowing through the radiator... In turn meaning either blocked radiator or dead water pump.

 

[large1]

update

right checked all fuses and they are fine, put jump leads on and sprayed wd40 in top of throttle body took off ect wire and after awhile it started, running rough with the engine management light on cleared at high revs, started to tick over but rough sounded very rich and smelt sooty, when it started to get warm the fan came on but the radiator is cold and pipes are hot so i recon a new rad may help as it looks like its not that efficient and thats why heaters probably had to be on before, now its not starting again, its got a prob with a wire that goes into ecu on ns strut and on the left plug, so today i sprayed it with wd40 and now it wont start again bloody thing, moved wires which normally works but wont start at the moment, ill let wd40 dry out maybe it will start then

so to clarify

fuses ok
fan ok
sanded earthes
radiator dont get hot

ive ordered ect sensor, thermostat, ill try these and see what happens

any input is greatly apprec thanx mick

 

[fingers99]

It needs (at least):
*new stat
*visit to the auto-electrician if you're having to mess around with the ECU connectors (connector to the ECU probably needs re-pinning)
*new water pump is as likely as new radiator (try running a hose through it -- if water flows out 't'other end OK then the chances are the rad is OK
*compression test

 

[large1]

It needs (at least):
*new stat
*visit to the auto-electrician if you're having to mess around with the ECU connectors (connector to the ECU probably needs re-pinning)
*new water pump is as likely as new radiator (try running a hose through it -- if water flows out 't'other end OK then the chances are the rad is OK
*compression test

ive not messed with ecu plug mate only removed sprayed and replaced nothing else

water pump seems fine flowing strong back to header tank ive just been reading the tech manual tbh it not as good as my autodata on why it wont start etc, ill get my mates snap on compression reader to test pressures, what should they been with/without throttle pressed

thanx again mick

 

[large1]

autodata attached for not starting

 

[fingers99]

You're not really looking for a figure, just equal compressions on each cylinder (throttle fully open -- I've never heard of anyone doing a compression test with the throttle shut!).

10 bar on each cylinder would be acceptable.

its got a prob with a wire that goes into ecu on ns strut and on the left plug, so today i sprayed it with wd40 and now it wont start again bloody thing, moved wires which normally works but wont start at the moment,

ive not messed with ecu plug mate only removed sprayed and replaced nothing else

I think you're drowning. Might be time to call in the lifeguards.

 

[large1]

I think you're drowning. Might be time to call in the lifeguards.

pmsl ill get to the bottom i always do so lol so around 140 psi that what i work in lol, i just want to get rid of the em light, would the wd40 in the throttle body of done any damage it ran better before even with the overheating prob, might get some carb cleaner to see if that helps

after all i may need helpppppp:bang:

 

[Pep0]

environmently friendly disposal of WD40 suggested.
the ECU is probably ok the light tells you that pulling multi way connectors indicates lack of caution wiggling is normally sufficient
spraying aerosols into TB invites starting by Desiel and a cunning way of attempting to blow a head gasket

you need to address the rad or pump

replace the thermostat first just in case

then if the heater is really hot then the rad is probably blocked
otherwise the pump is kaput

you could measure the resistance of the temperature sender by removing cable and using multi meter check the cable end for physical damage as well note the EML will be on if temp sender circuit is open or short circuit.

if it does not start listen for pump running (priming) when ignition is first turned on

if it primes then check for spark undo lead and attach to plug laying on cam shaft cover.

but also check for disconnected wires

 

[fingers99]

pmsl ill get to the bottom i always do so lol so around 140 psi that what i work in lol, i just want to get rid of the em light, would the wd40 in the throttle body of done any damage it ran better before even with the overheating prob, might get some carb cleaner to see if that helps

after all i may need helpppppp:bang:

Chances are that a little WD40 won't have done any harm. Where are you? Might be someone friendly with swimming trunks nearby!

 

[large1]

Might be someone friendly with swimming trunks nearby!

environmently friendly disposal of WD40 suggested.
the ECU is probably ok the light tells you that pulling multi way connectors indicates lack of caution wiggling is normally sufficient
spraying aerosols into TB invites starting by Desiel and a cunning way of attempting to blow a head gasket

you need to address the rad or pump

replace the thermostat first just in case

then if the heater is really hot then the rad is probably blocked
otherwise the pump is kaput

you could measure the resistance of the temperature sender by removing cable and using multi meter check the cable end for physical damage as well note the EML will be on if temp sender circuit is open or short circuit.

if it does not start listen for pump running (priming) when ignition is first turned on

if it primes then check for spark undo lead and attach to plug laying on cam shaft cover.

but also check for disconnected wires

thanks guys im in brighton, the heaters used to run really hot before the hg went last time, im going to probably replace the rad but i want it running half decent first

1) im replacing stat
2) im replacing ect sensor(green sensor near stat)
3) probably rad there only cheap

fuses all ok and the fan worked today but didnt this time when over heated so removing the ect wire obviously kicked the fan in, so relay must be fine even thou i couldnt find the fan relay in the tech sheets.

im just hoping its going to start now, ill also see if i can get the piston comp checker tom, working over weekend so i cant get on it and mondays meant to be evil so ill hopefully get some time on it soon, otherwise the missus wont be happy

thanx mick

 

[Pep0]

thanks guys im in brighton, the heaters used to run really hot before the hg went last time, im going to probably replace the rad but i want it running half decent first

1) im replacing stat
2) im replacing ect sensor(green sensor near stat)
3) probably rad there only cheap

fuses all ok and the fan worked today but didnt this time when over heated so removing the ect wire obviously kicked the fan in, so relay must be fine even thou i couldnt find the fan relay in the tech sheets.

im just hoping its going to start now, ill also see if i can get the piston comp checker tom, working over weekend so i cant get on it and mondays meant to be evil so ill hopefully get some time on it soon, otherwise the missus wont be happy

thanx mick

nooooooo you run the auto on tick over and if the heater is really hot but the rad is cold the thermostat is not opening or the rad is blocked
otherwise if the rad and heater are luke warm replace the pump
the pump is cheaper than the rad both are difficult to access & the pumps can fail even at low mileage

 

[large1]

UPDATE

got out to the car today, i changed the ect and the car started straight away, so that was a good start but running seriously rich.

i then removed all plugs and they are all sooted so its running super rich

checked all comps and they were all level 175 psi so that looks ok, thing is the car ran ok at first once cooled down after overheating, now since i put the wd40 in its not running well at all, before i replace the other stuff id like it running properly, maybe the head gasket has gone and thats what causing the problem im out of ideas

please helpppp meeeee:bang:

thanx mick