spsm11 Posted October 8, 2023 Share Posted October 8, 2023 Hi Folks, 2003 R300 K Series (dry sump, gold oil pump)My oil pressure gauge has started dropping out when I rev the car, it displays a good pressure at idle but above about 2000 RPM the gauge sometimes drops to zero (with the car being driven or revved out of gear). Please see the video below. Any ideas why this might be? I am using the standard oil pressure sender which I know can be dodgy, but I haven't found anything about this failure mode before... Thanks! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 8, 2023 Member Share Posted October 8, 2023 It looks like an electrical fault. And that it isn't affecting other instruments.Do you have a multimeter and would you like the appropriate wiring diagram?Any recent work on it?Jonathan Link to comment Share on other sites More sharing options...
spsm11 Posted October 8, 2023 Author Share Posted October 8, 2023 Yes, I have a multimeter and a wiring diagram would be super!No electrical work to speak of though I had the sump off a while ago, but not sure that correlated with this starting. Thanks!S Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 8, 2023 Member Share Posted October 8, 2023 Private Message sent.Jonathan Link to comment Share on other sites More sharing options...
revilla Posted October 8, 2023 Share Posted October 8, 2023 The way that drops off so abruptly at about the same engine speed every time screams sender failure to me. The sender just has a wiper that moves along a variable resistance track. Looks to me like the track is broken or worn and above a certain oil pressure it just disconnects and reads 0 again. Link to comment Share on other sites More sharing options...
John Vine Posted October 8, 2023 Share Posted October 8, 2023 #5 I agree. Time to consider a mechanical OP gauge. Reams on this in the archives.JV Link to comment Share on other sites More sharing options...
Gridgway Posted October 8, 2023 Share Posted October 8, 2023 Or just the remote mounting kit which has worked well for me in the past. Link to comment Share on other sites More sharing options...
John Vine Posted October 9, 2023 Share Posted October 9, 2023 #7 That's certainly an option as engine vibration very likely killed the original sender. But the OP would still need a new (and expensive) sender, whereas going mechanical would be much cheaper and more reliable.JV Link to comment Share on other sites More sharing options...
Gridgway Posted October 9, 2023 Share Posted October 9, 2023 #8 good point John, hadn't really thought of the comparative costs, assumed they would be similar. Also I don't like changing guages in the dash, very fiddly! Link to comment Share on other sites More sharing options...
spsm11 Posted October 11, 2023 Author Share Posted October 11, 2023 Thanks for all your help everyone, will do some wiring investigations but will probably end up switching over to a mechanical one eventually! Link to comment Share on other sites More sharing options...
SM25T Posted October 12, 2023 Share Posted October 12, 2023 It takes about 20 minutes to swap to a mechanical gauge .... Link to comment Share on other sites More sharing options...
East Kent AR Posted October 12, 2023 Share Posted October 12, 2023 Where are you based. I have an R300K and have a working spare sender I can lend you to test it, assuming your local to me of course.Piers Link to comment Share on other sites More sharing options...
Gridgway Posted October 12, 2023 Share Posted October 12, 2023 With the ages concerned it's probably ok, but ISTR they changed from fine to coarse pitch or the other way around, so if you do try a spare, double check the thread pitch is the same. Very easy to see the difference. Link to comment Share on other sites More sharing options...
Area Representative Andrew Gilbert Posted October 12, 2023 Area Representative Share Posted October 12, 2023 Sounds electrical, Mind you years back, Our new TVR with a ford cologne engine had the same issues, I'd run it in (remember those days!) then suddenly pressure dropped to 0 when we hit 3k, let up the accelerator it came back to normal, thought it was electrical, but no it was the oil pump! New engine. Had to run it in again.Good luck, keep us informed. Link to comment Share on other sites More sharing options...
Gridgway Posted October 12, 2023 Share Posted October 12, 2023 I lost OP from my BDG earlier on in the year and I didn't get to the off switch in time But I'd be pretty sure this is the sender - classic symptoms. The vibration does it. Link to comment Share on other sites More sharing options...
jackb_ms Posted October 12, 2023 Share Posted October 12, 2023 If required I have a spare gaugeJack Link to comment Share on other sites More sharing options...
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