heater plugs only operating when really cold

[richhall]

AS per the title my 1993 Audi 80 1Z heater plugs are only operating when really cold, so on these mild early mornings the old girl cranks over for quite a while before starting with a cloud of smoke, yet when there is a reasonable chill in the air she is running on first crank & no smoke, only when we have a frost does the heater plug warning light come on.
the old girl now has done 243,000 miles ( past the moon & on way back to the home world, as moon is 238,500 miles away!) are the heater plugs controlled by the coolant temp sensor ?
2 other problems that have started happening are that sometimes when you remove foot from the throttle then try & accelerate again there is no response until you dip the clutch or coast down to below approx 1200 rpm then throttle works again. This has been happening for the past 3/4 years sometimes it will do it 3-4 times a day then nothing for a month. Replaced the throttle pedal actuator unit when this first started happening but now just live with it.
Then earlier this year the oil pressure light did not go out so immediately stopped, carried out oil pressure check & all ok so replaced the switch ,again this still happens once a month or so.

Any clues on these problems???

[Lukenkarl]

Zollaf is your man for these cars

[micheal balbrig]

Heater plugs are working the same as any of my 80 1z did
Some say to remove temp sensor connector to see if any improvement. not sure if its the grey or blue one, try both at different times.
These engines are normally very easy to start and seldom need help from heat plugs until near freezing point.
The throttle response may be a faulty actuator on fuel pump,there was a similar problem in an old post a few years back and the actuator was the cause.
The oil light problem may just be a cable that lost its insulation and possibly shorting, possibly around oil filter area.

[zollaf]

indeed, i just jump in mine and start her up, never bother waiting for the plugs to even heat up and she always starts first flick. if it is really cold then i have to give them a few seconds. this is when running on derv. veg oil i always do let the light go out.
there are 2 oil pressure sensors on these, the low rpm, upto 2000 rpm, and the 2000 rpm plus one. did you change the right one.

[richhall]

Thanks for the replies, first question where is the second oil pressure switch?have changed the one on the filter housing.. Our supplier of veg oil gave up a few years ago here on the isle of man so on Derv, but agree when cold they require more cranks, but unless I have a good thick frost on the car the plug light does not come on, so will try disconnecting the temp sensors , will this make the light operate by putting it into a get u home mode ?
Any clues on where I can find the throttle actuator thread?

[micheal balbrig]

It appears that the post from 2010 must have been removed / deleted,but the acceleration problem was same as yours and it was cured by fitting a
different electronic box on fuel pump.

[richhall]

Heater plug prob seems to be the blue temp sender, light comes on when disconected & instant start thanks

[helmsy157]

Hi, yes, the blue sensor is used by the ecu to measure engine temperature and how long preheat should be