Oil light flicking, on idle when warm

[Hornsey Boy]

Hi All

I have a wedge HC turbo and the red warning light on the dash flickers when the oil ( 20W/50) is nice and warmed up on idle. But when I pull away from idle it goes out (once the revs go over 1,500rpm odd)

The term "tell tale" red relay pops on the forum search. Can anyone explain this and if if can be fixed ?

Thanks

 

[Barrykearley]

On the later cars I understand that the red low oil pressure light isn’t active unless the rpm is above about 1500rpm. The engines are known to have lower oil pressures when hot.

[ekwan]

On 01/09/2022 at 02:53, Hornsey Boy said:

Hi All

I have a wedge HC turbo and the red warning light on the dash flickers when the oil ( 20W/50) is nice and warmed up on idle. But when I pull away from idle it goes out (once the revs go over 1,500rpm odd)

The term "tell tale" red relay pops on the forum search. Can anyone explain this and if if can be fixed ?

Thanks

 

I would put a gauge on it first to make sure that you "really" have adequate oil pressure before anything else.

[philcool]

Obviously not the same car but a friend's 04 mini done the same after he changed the oil .

Light flicking on and off when warm when we investigated found the cheep oil filter he had used made of cardboard instead of plastic outer frame and  had deformed and not fully closed the oil drain valve from the oil filter housing to sump and so oil passing from the pump straight back to the sump.

We did change the oil pressure switch and that broke at 7psi and made at 5psi ie light on.

And that was a new switch anyway drained the oil which did have some white metel in it new propper Mann filter and all ok after that but obviously hasn't done his engine any favours.

So I would be fitting a gauge and checking the pressure and hoping it's just the oil pressure switch messing about 

[Hornsey Boy]

Thank Guys 

When we checked a while back the pressure was there. I have always used K&N oil filters and Millers 20w/50 oil.

I know the Esprit can be a mind field in regards of different oil pressure gauges and senders units etc used throughout the range over the years and I just wondered if there was something unique to the HC Turbo motor, hence coming across the term tell tale relay 

I will give PNM or SJ a call tomorrow to make sure I get the right sender unit.

 

[POD2100]

As per Barry my 87 TE HC doesn’t activate the tell tail at idle.

So low oil pressure at idle would only show on the gauge not the tell tail.

Perhaps the DECEL relay or a dodgy connection between the coil and the relay ?

 

[Hornsey Boy]

@POD2100 thanks Mark, the gauge shows some pressure on idle  i.e. not all the way down to zero.

I will check out the "DECEL" relay. I had a look in the manual, is that the one in the boot on the RH side ?.

I assume SJ sportscars will have them on their website.

Also notice a connection the throttle jack had been removed by the previous owner, reconnection it and when I blipped the throttle it idled at 2,000 rpm. So I disconnect it again. Not too sure if that is linked to my issue, or something else for me to look into 

[POD2100]

Yes the engine speed sense is done using the relay in the R/H rear arch.

the throttle jack solenoid, is only there to raise revs when using air con and to lower emissions on the over run.

When you blip it I would expect the revs to drop much slower than with the jack disconnected, however there is a procedure to set the amount the solenoid pushes up the throttle linkage.

If the throttle jack is off on idle but functions with an increase in revs then it sounds as if the relay is working as I would expect.

[POD2100]

So if yours is an 87 model turbo and I’m reading the schematic right.

the oil light only gets 12v over 1600rpm.

so find the relay and on idle (assuming it’s a bit under 1600 rpm) I would expect to see nothing between the Slate colour wire and a good ground. 
when you increase the revs this should go to 12v

When you drop the revs to idle you should have zero volts.

if not the DECEL relay may have iffy contacts?