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oil pressure gauge twitching

Discussion in 'Boxers/TR/M' started by lasvegascop, Sep 13, 2009.

  1. lasvegascop

    lasvegascop Karting

    Apr 12, 2009
    222
    Las Vegas, NV
    Full Name:
    "Ski"
    For some strange reason my oil gauge starts to twitch when the RPM go up? Probably around 3K-4K sometimes the needle goes to 0, but I know its a short cause sometimes it stays where its supposed to.
    I got under and cleaned both of the oil pressure sensor leads, eveb applied some dyelectric grease. Still the same, so it cant be the wiring, or can it? Is my sensor thinking about taking a dump? It has to do with vibration or possision of the torqued engine pulling something to the side? Geez its frustrating!

    Has anyone experienced anything like that and has a quick solution? Everything is perfect on my car except for that darn oil gauge!

    Ski
     
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  3. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
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    Shamile
    Dear Ferraristi,

    So, you cleaned the leads off the sensor....how about the ground coming off the gauge?

    Pull the dash pod and try cleaning the gauge wires. Most intermittent gauges I've seen was because of a bad ground (dirty connector)

    Let us know if that solves it.

    Or....

    Steve M will have to give you a full run through of the wiring....where it's coming and where it's going. :)


    Shamile

    Freeze...Miami Vice !
     
  4. lasvegascop

    lasvegascop Karting

    Apr 12, 2009
    222
    Las Vegas, NV
    Full Name:
    "Ski"
    hmmmmmm.....I just have that feeling that the problem is close to the engine and maybe not by the gauge or the ground by the gauges? It's just because of the higher RPM scenario...you know?

    Ski
     
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,279
    Texas
    Full Name:
    Steve Magnusson
    #4 Steve Magnusson, Sep 13, 2009
    Last edited: Sep 13, 2009
    I believe it would actually be an "open" somewhere rather than a "short" causing your problem (if the trouble isn't inside the dash gauge itself) -- i.e., if the HN (grey/black) wire going to the sender is disconnected = gauge goes to zero; if the HN wire is connected to ground = gauge goes to maximum (you might confirm/deny this logic just to be sure).

    This HN (grey/black) wire also passes thru the square 9-pin C11 connector under the coolant expansion tank so the easiest thing to do first is just unplug/inspect/reseat this C11 connector (since you've already done that at the sender). If that doesn't do it, give a shout, and we can go deeper -- but it will be more work/hassle ;)

    You also mention "I got under and cleaned both of the oil pressure sensor leads". The schematic shows only one wire (the HN wire) and the body of the sender being directly connected to ground (and I'm not going to get under my TR to check things out ;)). If there is a physical second (usually black) wire at the sender (and sometimes this is a short jumper wire directly connected to a local ground) -- you could: 1) make sure its local connection to ground is clean/tight, per Shamile's suggestion, or 2) add (or replace) another temporary jumper in parallel from the ground terminal on the sender that is connected to this ground wire to a good local ground.
     
  6. lasvegascop

    lasvegascop Karting

    Apr 12, 2009
    222
    Las Vegas, NV
    Full Name:
    "Ski"
    I meant to say both pressure senders (one for the gauge and the other one for the light, right?) not both wires. But yes, I cleaned it all.

    I will be digging into that 9th pin and see whats going on in there. I bet thats' where the problem is ;) Its close to the engine and hi RPM vibrations...

    Thank you for giving me something to work with, now lets hope it works. I realllllly dont wanna start digging under the dash ARGHHH

    Ski
     
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  8. lasvegascop

    lasvegascop Karting

    Apr 12, 2009
    222
    Las Vegas, NV
    Full Name:
    "Ski"
    Ok...I took the C11 connector and cleaned the crap out of it. Chemically and physically, then cleaned it again with the brake cleaner to get the chem's off, I then applied thin dielectric grease and plugged all together again.

    Took the car for a spin and its the SAME THING!!

    I looked under the dash..geezzzzz, I cant see a thing! I do see some wires so I was thinking about maybe tapping into the pos lead that goes to the gauge (oil of course) and checking it with the ohm meter while I'm driving to see if the values increase/decrease and if I lose the signal all together?

    I'll keep ya posted.

    Ski
     
  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    20,279
    Texas
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    Steve Magnusson
    Yes, somehow the TR Gods never let it be the easy fix ;)

    One other thing you might consider is:

    1. measure the resistance from the wire terminal on the sender to ground when the engine is running (and the oil pressure is at some mid-level value on the gauge).

    2. remove the HN wire from the sender and connect it to a fixed resistor having roughly the same resistance value, and connect the other side of the resistor to ground (i.e., replace the sender with a fixed resistor).

    If the problem goes away (i.e., the gauge reads steady), then you could try a new sender without much regret IMO, but

    If the problem is still there -- probably says it's not the sender, and you have to go after the gauge/dash wiring/gauge connections/etc..

    Just a thought...
     
  10. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
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    Shamile
    Dear Ferraristi,

    Yeah, I too have that feeling.... when I buy the chick a drink thats diggin me.....only to have her walk away.....with the drink I just paid for. :)



    Pulling the dash pod is not difficult. Under the dash, you will see two bolts (one on either side. Undo those and pull the pod up and towards the windshield (clip holds the pod where it meets the dash surface )

    ...no circuit boards....just wires....at least it CAN be fixed. :D


    Shamile

    Freeze....Miami Vice !
     
  11. lasvegascop

    lasvegascop Karting

    Apr 12, 2009
    222
    Las Vegas, NV
    Full Name:
    "Ski"
    You're kidding!??!!??!?!!? that's it? 2 screws? I saw them when I looked under the dash...and BTW, I found that grey/blk wire in a snap! I connected the ohm meter and the volatage while driving was between 5-8V at around 3500 RPM. The voltage never dropped to zero but the gauge went down to 0 several times.
    Man I'm thinkinh maybe its the gauge that's thinking about taking a dump? Have you ever had a gauge fail? Would it be all at once or would it have simptoms like mine? Only at higher RPM's and not always?...

    I think I might take the dash apart like Shamile said since it's easy and quick( I thought it would be a 3 day process!!!???)

    Maybe I can just spot me an Oil press gauge and just install it and see what happens?

    Ski
     
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  13. bazzis

    bazzis Karting

    Nov 5, 2003
    217
    Sarratt, Herts
    could you replace sender unit with a mechanical gauge, just to check......
     
  14. lasvegascop

    lasvegascop Karting

    Apr 12, 2009
    222
    Las Vegas, NV
    Full Name:
    "Ski"
    Dont have any mech ones right at this moment ;(
     
  15. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
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    Shamile
    Dear Ferraristi,

    No...not the dash...just the instrument pod. To make thing easier, you may want to remove the steering wheel and the leather piece under the pod between the knee bolster (1 screw)

    Once you pull the pod, pull the gauge and have it tested if you suspect the gauge itself.

    ...just a thought,

    could the gauge internal contact points be dirty? The actual wire points that controls the electromagnet on which the gauge needle rides?

    Shamile

    Freeze....Miami Vice !
     

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