Oil Pressure Reading / No Stop Light

[joni 0]

Just rebuilt my 205 1.9 engine with new rings and bearings. Reassembled everything put it in, turned the key and it fired up - great!

 

BUT.... no oil pressure reading. when you turn on the ignition the gauge goes to full but as soon as you start it up the gauge drops to zero and doesnt respond in any way to throttle. The oil temp gauge appears to work as do all the other gauges and the oil pressure gauge did work before the engine change.

 

I noticed that the STOP light doesnt come on when the ignition is switched on either. So i thought this might be bulbs in the dash or related to the gauge problem????

 

Any ideas guys? Theres 2 sensors on the block near the alternator which i assume could be related to the problem. i am pretty sure i put the right wires back on and they look like they agree to the pictures i took as i disconnected everything. What are these two sensors and which is which?

 

Hope someone can help.

 

I'm crossing my fingers that i do actually have oil pressure after the rebuild and havent put it back togetehr incorrectly! i drove 10 miles and back for an MOT and it had no problems (apart from failing for a hole in the inner sill next to the fuel tank)!

[smckeown 1]

The one nearest the alternator is the pressure sender, the one to it's right is the stop light switch. As both are playing up it indicated bad wiring, as they are independently wired I believe

Edited January 4, 2007 by smckeown

[miamistu 1]

As Sean says, this sounds like your wiring is wrong. I'd guess your pressure sender and stop switch are wired the wrong way round which would account for the gauge going to full when you turn on ignition. Swap these round and I'd guess you'll be sorted

[joni 0]

nice one lads, will try it out on Saturday and let you know. What you say makes sense so fingers crossed and i'm keeping the other ones crossed for a 3/4 gauge reading after the engine build!

[jackherer 543]

As miamistu has suggested, this is definitely how they behave when the two oil pressure sender wires are swapped over.

[joni 0]

As miamistu has suggested, this is definitely how they behave when the two oil pressure sender wires are swapped over.

 

Yep you guys were right the stop light and pressure gauge now work as they should after i switched the wires. The oil pressure reading isn't great - it gets to the 3rd white line when driving along with some revs and drops to the middle (vertical) position when at idle - possibly lower when warm.

 

I was expecting better but i wondered whether the reading showing on the gauge may be affected by the gauge itself and hte sensor. Perhaps if i was to change one or both of these i might get a different reading?

 

My last 205 1.6 gti had a really strong pressure reading (half way between middle and full on the gauge). Should i be concerned or do the readings i'm getting seem ok?

[smckeown 1]

good stuff.

 

Yes starting with a new pressure sender is a good idea, then you can be sure the readings are right. Some people even doubt the gauge.

[taylorspug 7]

I would take all of the stock gauge readings with a pinch of salt TBH. All the senders seem to read different, even in the same car. My cars oil pressure sits just about at the 1st white line at idle, then goes up to vertical when driving. The engine itself is in the best of health as its had a partial rebuild recently, its just the way the gauge is. As long as the low pressure light doesnt come on or the engine doesnt sound like a bag of nails then i wouldnt worry.

 

Alternatively go to a garage that has a master gauge so they can check the pressure and give you an accurate reading.

[Richie-Van-GTi 70 2 Cars]

most 205's ive been in have oil pressure as you described, dont worry about it. As long as you have oil pressure and the car runs right then just ignore the gauge.

[joni 0]

Cheers lads, i might get a new sensor the next time i have the alternator off just to try and get a better reading as it makes me happier to see a fuller gauge reading! May be because in the past i've had an engine with such low pressure that the stop light came on (due to worn bearings) so i don't like seeing the needle so low!

[jackherer 543]

Perhaps if i was to change one or both of these i might get a different reading?

 

I'm pretty certain that if you changed either you'd get a different reading simply because the dash and the senders are so vague and innaccurate. IMO you would do best to fit an aftermarket gauge and sender if you actually want to know whats going on with the oil pressure.