P38 Paul Posted July 26, 2019 Share Posted July 26, 2019 Hi peeps , the glow plugs on my car don't seem to be working so I recon the first port of call is going to be the glow plug relay , what do you think & where is it situated ? Hope you are all well regards Paul . Quote Link to comment Share on other sites More sharing options...
teabag Posted July 26, 2019 Share Posted July 26, 2019 (edited) It can be found in the engine bay relay/fuse box which is I believed behind the battery. also there’s a lot of info on a P38 diesel failure to start, here’s a link to just one of the threads available https://www.brit-car.co.uk/product.php/92971/5497/heater_plug_relay_bmw_diesel_p38_range_rover https://rimmerbros.com/Item--i-STC3364 Edited July 26, 2019 by teabag Additional links Quote Link to comment Share on other sites More sharing options...
Escape Posted July 29, 2019 Share Posted July 29, 2019 Actually, the relay is not in the fusebox, but in the same box as the ECU, between the battery and fusebox. As said, make sure the plugs are indeed not working. Often poor starting of a P38 diesel is due to a worn injectionpump. Filip Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted July 29, 2019 Author Share Posted July 29, 2019 Hi Teabag & Filip , just to update my first post a bit , the glow plugs were replaced at the start of the month so I don't recon all six have gone faulty but as I said in the first post ( they don't seem to be working ) also the dashboard light is not illuminating , the FIP was renewed two years ago so I recon that is not the fault , also this happened all of a sudden , it started with no problem first thing in the morning with no problem & then it wouldn't start 12 hours later when I wanted to come back home , Quote Link to comment Share on other sites More sharing options...
Escape Posted July 30, 2019 Share Posted July 30, 2019 With new glow plugs, I agree the relay/timer module is a likely suspect. However, the dashboard light is not controlled via the timer module, but by the BECM that receives a signal directly from the engine ECU. Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted July 30, 2019 Author Share Posted July 30, 2019 12 hours ago, Escape said: With new glow plugs, I agree the relay/timer module is a likely suspect. However, the dashboard light is not controlled via the timer module, but by the BECM that receives a signal directly from the engine ECU. Ok Filip , what shall I go for , I think the relay is the first suspect & scrap the car off if its the BECM 😉 Quote Link to comment Share on other sites More sharing options...
Escape Posted July 31, 2019 Share Posted July 31, 2019 Checking the relay works is easy, so start there. If it checks out, I'd see if it actually gets the command signal from the engine ECU. If not, a bad connection seems a likely cause (BY and BR wires). The BECM doesn't control the glow plugs, it just transmits the signal from the engine ECU to the dash, so no worries there. If you have diagnostics, it's a good idea to check the engine temperature. A fault in the sensor or wiring could cause the engine ECU not to turn on the glow plugs. And inject less fuel, making it hard/impossible to start. Filip Quote Link to comment Share on other sites More sharing options...
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