Oil pressure question on Chimaera 400
Oil pressure question on Chimaera 400
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Discussion

Nick P

Original Poster:

29,977 posts

281 months

Sunday 3rd September 2006
quotequote all
The Chimaera i bought yesterday has the red light on the bottom of the dash on constantly.
The guy who had it said it was a wiring problem and it has been on for 6 months or so. The paperwork seems to back this up as it was investigated by a garage.
Looking in the handbook, it says it is the oil light and i agree.

However, the oil pressure gauge is showing good pressure, so I tend to agree that it's a wiring fault.....

now my question is.......is there more than one pressure sensor on the engine (I sold my Steve Heath bible when i sold my last Chim), or could there be an actual problem with the oil circulation?

There are no knocking noises, tapping or rattles and the pressure gauge show anywhere between 20psi-60psi depending on how revs/temp etc.

Apart from annoying, I'd like to clear the issue up, as I am a pedantic bastard and want my car to be perfect!!!!!

**Please can we leave it in here rather than putting it in the Chimaera forum as i want max exposure and it is applicable to all RV8s** Thanks

Edited by Nick P on Sunday 3rd September 14:45

antonyj

5,254 posts

311 months

Sunday 3rd September 2006
quotequote all
Errr , maybe I will be corrected, but the red light in these cars is usally the ignition light , the yellow one is the oil pressure.



Edited by antonyj on Sunday 3rd September 15:04

Nick P

Original Poster:

29,977 posts

281 months

Sunday 3rd September 2006
quotequote all
antonyj said:
Errr , maybe I will be corrected, but the red light in these cars is usally the ignition light , the yellow one is the oil pressure.



Edited by antonyj on Sunday 3rd September 15:04


really? thats good news then. The bloke i bought it off said it was a charging fault, but i thought he was wrong. He'd even put a new alternator in. Hopefully, i'm wrong then.
In the handbook, it shows the bottom LED as the oil on. Its a 94 Chim, so an early one.
I was worried i had bought one with an oil pressure problem for a bit
*phew*

GreenV8S

31,018 posts

314 months

Sunday 3rd September 2006
quotequote all
You should have two lights that come on with the ignition, and go out once the engine is running. There's an easy way to tell them apart. Rev the engine up to say 3000 rom and then switch off. The no charge warning light will come on immediately. The low oil pressure warning light will only come on shortly after the engine has stopped.

If the low oil pressure warning light is on permanently that implies that the sensor or the wire to the sensor is permanently earthed. If you disconnect the sensor, this would tell you which it was. Since somebody has failed to fix this in the past I'd guess it is the wire, because as faulty sensor would be trivially easy to diagnose and fix. Fixing a damaged wire would involve some grovelling round behind the dash so rather more time and money. It's worth doing though, because that warning light could save your engine one day.

Nick P

Original Poster:

29,977 posts

281 months

Sunday 3rd September 2006
quotequote all
GreenV8S said:
You should have two lights that come on with the ignition, and go out once the engine is running. There's an easy way to tell them apart. Rev the engine up to say 3000 rom and then switch off. The no charge warning light will come on immediately. The low oil pressure warning light will only come on shortly after the engine has stopped.

If the low oil pressure warning light is on permanently that implies that the sensor or the wire to the sensor is permanently earthed. If you disconnect the sensor, this would tell you which it was. Since somebody has failed to fix this in the past I'd guess it is the wire, because as faulty sensor would be trivially easy to diagnose and fix. Fixing a damaged wire would involve some grovelling round behind the dash so rather more time and money. It's worth doing though, because that warning light could save your engine one day.


the previous owner tried the grovelling thing and failed to find it. when i turn the ignition off, all the lights just go out, so i cant tell which is the oil pressure/charge circuit!!! He said it was a charging problem, but the handbook shows it as the oil.????????????????????????????????????????????

my only worry is that it's an oil pressure problem, which i dont think it is and i watch the pressure gauge like a hawk......i'm currently trying to buy a bible then i can start digging rolleyes

oh the joys of TVR ownership hehe

tvr4ever

644 posts

290 months

Sunday 3rd September 2006
quotequote all
Nick P said:
The Chimaera i bought yesterday has the red light on the bottom of the dash on constantly.
The guy who had it said it was a wiring problem and it has been on for 6 months or so. The paperwork seems to back this up as it was investigated by a garage.
Looking in the handbook, it says it is the oil light and i agree.

However, the oil pressure gauge is showing good pressure, so I tend to agree that it's a wiring fault.....

now my question is.......is there more than one pressure sensor on the engine (I sold my Steve Heath bible when i sold my last Chim), or could there be an actual problem with the oil circulation?

There are no knocking noises, tapping or rattles and the pressure gauge show anywhere between 20psi-60psi depending on how revs/temp etc.

Apart from annoying, I'd like to clear the issue up, as I am a pedantic bastard and want my car to be perfect!!!!!

**Please can we leave it in here rather than putting it in the Chimaera forum as i want max exposure and it is applicable to all RV8s** Thanks

Edited by Nick P on Sunday 3rd September 14:45


Mine has been mildly glowing for ages, i think because it's LED it doesn't need much current to glow. It may have something to do with current leaking somewhere behind the dash or a bad ground. After installing a lights buzzer my LED started glowing.
No need to lay awake at night i would say.

I'm sure some electronics wizard will come along and give a detailed explanation.

Fred

Nick P

Original Poster:

29,977 posts

281 months

Sunday 3rd September 2006
quotequote all
so the bottom LED of the 3 is the charge indicator?

If it is, i'm not worried at all because i know the charge circuit works.

My only worry is that it is the oil light and i just wondered why its on.

GreenV8S

31,018 posts

314 months

Sunday 3rd September 2006
quotequote all
Nick P said:
when i turn the ignition off, all the lights just go out


Have you actually tried this, revving the engine before you switch off? Mine most definitely lights the no charge warning as the engine spins down, and the circuit to the alternator is pretty simple and not that much scope for variation I'd have thought.

Nick P

Original Poster:

29,977 posts

281 months

Sunday 3rd September 2006
quotequote all
ok...been out for a drive in the dark......

i rev to 4000 revs, then put the clutch in and turn the ignition off simultaneously.

the lower light stays on for a bit and the middle yellow light goes off immediately.

i think i'm correct in thinking that this confirms the lower (red) LED is the charge one?

if so, thats ok.

thanks for your help greenv8s

GreenV8S

31,018 posts

314 months

Sunday 3rd September 2006
quotequote all
Nick P said:

the lower light stays on for a bit and the middle yellow light goes off immediately.

i think i'm correct in thinking that this confirms the lower (red) LED is the charge one?



Yes that's what it means, but from those symptoms I'd suspect the 'other' light is probably the handbrake light not the low oil pressure warning light. Are you sure you're looking at the right two lights?

Nick P

Original Poster:

29,977 posts

281 months

Sunday 3rd September 2006
quotequote all
well i only have 3 leds in front of me !!!!

top is red and is something to do with the immobiliser cos it flashes when the alarm is set and flashes when i pip the key

middle is yellow and goes out when engine running

bottom is red and stays on permanently apart from when ignition is off


ho hum.......

smb

1,523 posts

296 months

Monday 4th September 2006
quotequote all
unfortunately position of the lights varied by who built it, loads of cars are different. when u look at the wiring behind the dash, there are loads of power blocking diodes, I suspect u have some leakage issue.

Nick P

Original Poster:

29,977 posts

281 months

Monday 4th September 2006
quotequote all
smb said:
unfortunately position of the lights varied by who built it, loads of cars are different. when u look at the wiring behind the dash, there are loads of power blocking diodes, I suspect u have some leakage issue.


so really its pot luck which light is which?!!!! rolleyes

however, having done the 'rev test', i'd be pretty happy it was the charge light....

kenny chim 4

1,604 posts

288 months

Tuesday 5th September 2006
quotequote all
Nick, from your description of the car I would confidenty state the the red, lowermost, lamp is the battery charge indicator.

Despite the previous owner's assurances, I'd get the fault checked out. It's there as a warning indicator afterall and shouldn't be ignored TBH.

The (top) yellow lamp will be your oil pressure incidently- despite what the handbook says.
Good luck with the new car. You will love it

Nick P

Original Poster:

29,977 posts

281 months

Tuesday 5th September 2006
quotequote all
kenny chim 4 said:
Nick, from your description of the car I would confidenty state the the red, lowermost, lamp is the battery charge indicator.

Despite the previous owner's assurances, I'd get the fault checked out. It's there as a warning indicator afterall and shouldn't be ignored TBH.

The (top) yellow lamp will be your oil pressure incidently- despite what the handbook says.
Good luck with the new car. You will love it


cool....thats good news.

I am enjoying the car......it's almost identical to my last one, so am remembering all the good points and the not so good points hehe