Guest Posted March 1, 2014 Share Posted March 1, 2014 Go gently. First post on TechTalk with you big boys. Getting used to 7 and went out for quicky before football match. Oil pressure gauge wouldn't shift from 2 bar. Took it gently for 30 mins then pulled in worried. Then water temp hit 90 when stationary and oil pressure went up to 6bar. I assumed oil pressure had nothing to do with operating temperature. So sticking dial? (Tapped it a lot like they do on the movies, to no avail). Poor sender/ sensor?. Poor operator knowledge? I await your responses with my tin hat in hand. Oh forgot. Sigma 140 supersport upgrade done just before I purchased. Originally 2years raced in academy and roadsport series by previous owner. Purchased Xmas, 4 gently run out since Xmas And oil pressure always up to between 4and6 each time. Edited by - Upstoke on 1 Mar 2014 22:41:57 Edited by - Upstoke on 1 Mar 2014 22:50:54 Link to comment Share on other sites More sharing options...
ChrisC Posted March 1, 2014 Share Posted March 1, 2014 It doesn't sound right to me, my 150 oil pressure starts hight when cold, but drops at idle when the oil heats up. So the question is, where is the problem, gauges, electrical or a engine problem. I have the easimap connection lead to see if the ecu is seeing a problem, or the engine is running fine. Do you know anyone local with a diagnostic lead? Link to comment Share on other sites More sharing options...
Ads7 Posted March 2, 2014 Share Posted March 2, 2014 If it still has the standard Caterham gauge this could be your problem. They are known to pack up as they are electrical. I now have a mechanical Guage which actually works and shows a proper pressure. Adam Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted March 2, 2014 Share Posted March 2, 2014 Does sound like an electrical sender problem. Mechanical gauge is cheap and easy to fit. Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted March 2, 2014 Area Representative Share Posted March 2, 2014 Upstoke, You have email. Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted March 2, 2014 Area Representative Share Posted March 2, 2014 Quoting SM25T: Mechanical gauge is easy to fit. Ian You obviously haven't tried on a Sigma. Sender is v. difficult to access. Link to comment Share on other sites More sharing options...
ChrisC Posted March 2, 2014 Share Posted March 2, 2014 The gauges take there supply from the tach, so are any of the other gauges playing up? If not try and get a resistance reading from the sensor wire by disconnecting the oil pressure gauge, if you tell me your resistance and engine condition I will post a comparison figure. I.e cold oil at idle I get x ohms. That should pin point gauge or sensor/wiring. Hope this helps. Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted March 2, 2014 Area Representative Share Posted March 2, 2014 Quoting Paul Richards: You obviously haven't tried on a Sigma. Sender is v. difficult to access. Paul, Having now looked at this car, I can see that you weren't kidding 😔 Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted March 2, 2014 Area Representative Share Posted March 2, 2014 Quoting ChrisC: The gauges take there supply from the tach, so are any of the other gauges playing up? If not try and get a resistance reading from the sensor wire by disconnecting the oil pressure gauge, if you tell me your resistance and engine condition I will post a comparison figure. I.e cold oil at idle I get x ohms. That should pin point gauge or sensor/wiring. Hope this helps. For reference, the Sigma uses a Danfoss MBS 1350 solid state transducer, and should produce 0.1 to 5V for 0-7bar. Having rigged this one up to a regulated air supply, and varied the air pressure, we saw 1.8volts at no pressure, and then random changes of voltage as I varied the pressure. I recon it's knackered! Link to comment Share on other sites More sharing options...
Guest Posted March 2, 2014 Share Posted March 2, 2014 Thanks for all your comments. Many thanks to Richard Price for offering to have a quick look at the problem only to find it took a huge chunk out of his Sunday. Sorry. I was next to useless but Richard wouldn't give up until fault was found. As he posted, sender knackered. Time to change to a mechanical unit and learn more about how to sort things myself. Thanks. Link to comment Share on other sites More sharing options...
ChrisC Posted March 2, 2014 Share Posted March 2, 2014 Quoting Richard Price: Quoting ChrisC: The gauges take there supply from the tach, so are any of the other gauges playing up? If not try and get a resistance reading from the sensor wire by disconnecting the oil pressure gauge, if you tell me your resistance and engine condition I will post a comparison figure. I.e cold oil at idle I get x ohms. That should pin point gauge or sensor/wiring. Hope this helps. For reference, the Sigma uses a Danfoss MBS 1350 solid state transducer, and should produce 0.1 to 5V for 0-7bar. Having rigged this one up to a regulated air supply, and varied the air pressure, we saw 1.8volts at no pressure, and then random changes of voltage as I varied the pressure. I recon it's knackered! Good work Link to comment Share on other sites More sharing options...
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